somta tools user guide
TRANSCRIPT
1
CUTTING TOOL MATERIALSSomta cutting tools are manufactured from the finest steelavailable. The heat treatment process is controlled by ourMetallurgical laboratory using advanced computerised andelectronic instrumentation. High Speed Steel contains variouselements such as Molybdenum, Tungsten, Cobalt and Vanadiumand must be specially heat treated to produce the idealcombination of strength, toughness and wear resistance.SOMTA products are manufactured from one of the following HighSpeed Steels depending on the product and application.
C Cr W Mo V Co Hardness (HRC) M2 0.9 4 6 5 2 - 63 - 65 M35 0.9 4 6 5 2 5 64 - 66 M42 1.1 4 1.5 9.5 1 8 66 - 68.5(70) M9V 1.25 4.2 3.5 8.5 3 - 64 - 66
M2 is the standard High Speed Steel and is used where toughnessis important, together with a good standard of wear resistance andred hardness.
M35 is a development of M2 and contains 5% cobalt which givesimproved hardness, wear resistance and red hardness. It may beused when cutting higher strength materials.
M42 can be heat treated to very high hardness levels of up to 70HRC (1 000 HV) although normally a slightly lower figure will beemployed to retain toughness. This steel is ideal for machining higherstrength materials and work hardening alloys such as stainless steels,nimonic alloys etc. Despite its high hardness, M42 has goodgrindability characteristics due to lower vanadium content.
M9V material is mainly used in the manufacture of machine tapsbecause of its good wear resistance, good grinding capabilities, highhardness and excellent toughness.
Cutting tools may shattereye protection should be worn
2
SURFACE TREATMENTSBright FinishA bright finish tool has no surface treatment and is suitable for generalpurpose use.
Blue FinishA blue finish is achieved by steam tempering - a thermal processwhich imparts a non-metallic surface to the tool. This surface isporous and by absorbing lubricant, helps prevent rusting, reducesfriction and cold welding, resulting in increased tool life.Steam tempered products can successfully be used at slightlyincreased machining rates or on more difficult to machine materials.
Gold OxideThis is a metallic brown coloured surface treatment achieved by alow temperature temper and is normally only used on cobalt productsfor identification purposes.
NitridingNitriding imparts a hard surface to the tool and is used for prolongingtool life and machining difficult to machine materials. Becausenitriding makes the edge more brittle, care must be exercised in thetype of application.Nitrided tools are normally also steam tempered.
Titanium Nitride Coating (TiN)TiN coating is a very hard, gold coloured surface coating a fewmicrons thick which is applied by means of a complex process, calledPhysical Vapour Deposition (PVD), by advanced modern equipment.The coating is non-metallic and therefore reduces cold welding.In certain applications increased speed and feed rates can beachieved because of:
(a) The hardness of the coating.(b) The reduction in cutting force required due to a decrease in
friction between the tool and the workpiece.Tool performance will deteriorate after re-sharpening.
3
TiCN (Titanium Carbonitride)The addition of carbon to TiN results in a significant increase in thehardness of TiCN over TiN. TiCN also has a much lower coefficientof friction which enhances the surface finish of components machinedwith TiCN coated tools, higher productivity can be achieved on awide range of materials but, in particular stainless steel, titaniumand nickel based alloys. It is now generally accepted that TiCNcoating has been superseded by TiAlN for most machiningapplications.
TiAlN (Titanium Aluminium Nitride)In addition to a higher hardness than both TiN and TiCN the aluminiumin the coating imparts a much greater oxidation stability. This is as aresult of a very thin film of (Aluminium Oxide) being formed on thesurface of the TiAlN. The film is self repairing, leading to additionalincreased service life. These improvements allow the coating towithstand much higher temperatures which in turn allows increasedcutting conditions, especially useful when machining Cast Iron andtough steels.
4
DRILLS
DRILL NOMENCLATURE
TANG
MORSE TAPERSHANK
BODYFLUTE
LENGTH
DIAMETER
RECESS
OVERALLLENGTH
HELIXANGLE
5
DRILL NOMENCLATURE
LIPCLEARANCEANGLE
DETAILED VIEW OF LIP CLEARANCE
BODYCLEARANCEDIAMETER
FLANK POINTANGLE
CHISELANGLE
WEBTHICKNESS
LAND
CHISELEDGE
LIPLENGTH
HEEL
6
SELECTING THE CORRECT DRILLDrills for general useThese twist drills are designed to drill the common materials undernormal operating conditions.The following standard drills are available ex-stock from Somta.
Jobber Drills
General purpose drilling.
Long Series Drills
General purpose long reach drilling.
Stub Drills
A short robust drill suited to portable drill applications.
Reduced Shank Drills 1/2” / 12,7 mm Shank
General drilling for use in hand power tools.
Left hand Jobber Drills
General purpose drilling in the left hand direction.
MTS Drills
General purpose drilling.
MTS Drills, HSS-Co
General purpose drilling in difficult materials.
7
Drills for specific applicationsMore efficient drilling can be achieved by using a drill designed for aspecific application.The following drills are available ex-stock from Somta.
Sheet Metal Drills
Self centring drill designed to produce accurate holes in thin materials.135° split point.
Double Ended Sheet Metal Drills
Self centring drill designed to produce accurate holes in thin materials.135° split point.
Tanged Jobber Drills
Designed to fit tang drive sleeve.
NDX - Heavy Duty Jobber Drills, HSS-Co
Drilling high tensile steels and other difficult materials. 135° splitpoint.
TiN Coated Jobber Drills
For drilling in a production environment where higher speeds and orfeeds are required.
Extra Length Drills
Extra deep hole drilling. (Details on page 18)
8
UDL Deep Hole Drills Long Series, HSS-Co
Parabolic Flute Form and Heavy Duty, for general purpose long reachdrilling.
UDL Deep Hole Drills Extra Length, HSS-Co
Parabolic Flute Form and Heavy Duty, for extra deep hole drilling.
UDL Jobber Drills, Long Chip, HSS-Co
Parabolic Flute Form and Heavy Duty, for use on NC and CNCmachines where high productivity and accurate holes are required.
UDL - Stub Drills, Long Chip, HSS-Co
Parabolic Flute Form and Heavy Duty, for use on NC and CNCmachines where high productivity and accurate holes are required.
UDS - Jobber Drills, Short Chip, HSS-Co
Parabolic Flute Form and Heavy Duty, for use on NC and CNCmachines where high productivity and accurate holes are required.
UDC - Jobber Drills, Cast Iron, HSS-Co
Parabolic Flute Form and Heavy Duty, for use on NC and CNCmachines where high productivity and accurate holes are required.
MTS Extra Length Drill
Extra deep hole drilling. (Details on page 18 & 19)
9
MTS Core Drills
For enlarging diameters of existing holes whether drilled, punchedor cored. (Details on page 21)
MTS Armour Piercing Drills, HSS-Co
Heavy duty drilling in work hardening and heat treated steels.
Drills for Special Applications
Subland Drills
For drilling stepped holes in one operation.Drill Reamers
For drilling and reaming holes in one operation (hole tolerance widerthan H7).Coolant Feed Drills
For drilling extra deep holes. (Details on page 19)Cotter Pin Drills
For heavy duty drilling using a tang drive sleeve.Somta Sorger
Patented Auger for wood drillingRail Drills
Developed for drilling work hardening railway lines. Alternative to theArmour piercing drill.
10
WORKPIECE MATERIAL
TYPE GRADE
CARBONSTEEL
&
ALLOYSTEEL
TYPICAL PHYSICALPROPERTIES
CODE TYPE
FREE CUTTING
0.3 to 0.4% Carbon
0.3 to 0.4% Carbon
0.4 to 0.7% Carbon
0.4 to 0.7% Carbon
HARDNESSBRINELL
(MAX)
TONS PERSQ.INCH
(MAX)
N / mm²(MAX)
STAINLESSSTEEL
HEATRESISTING
ALLOYS
TITANIUM
CASTIRONS
150
170
248
206
286
35
40
59
47
67
540
620
910
720
1030
Low Alloy Tool
Steels
High Alloy Tool Steels
Heat Treatable Steels
248
330
380
59
75
87
910
1150
1300
Martensitic
(400 Series)248
Austenitic (Work
Hardening)
(300 Series)
300
54
65
810
1000
Inconell, Hastelloy
Nimonic Alloys350 78 1200
Commercially Pure
Commercially Alloyed
275
350
65
78
1000
1200
Grey Irons
Nodular Irons
Malleable Irons
110 - 300 - -
MANGANESESTEEL
ALUMINIUM
MAGNESIUMALLOYS
COPPERALLOYS
PLASTICS
AS SUPPLIED
Wrought Alloys
Cast Alloys
Silicon Alloys
Moderately
Machineable Alloys
LEADED COPPER ALLOYSFREE CUTTING BRASS
MEDIUM TO HIGH LEADED BRASS
LOW TO HIGH SILICON BRONZEMANGANESE BRONZE
ALUMINIUM SILICON BRONZE
COMMERCIAL BRONZE 90%PHOSPHOR BRONZE 5 - 10%
ALUMINIUM BRONZE
SoftHardReinforced
Free Cutting Alloys
Difficult to MachineAlloys
DRILL TECHNICAL DATA
AS SUPPLIED
AS SUPPLIED
141 - 142
147 - 148
151 - 152
153� - 163�
STUBDRILLS
JOBBERDRILLS
101 - 102
105
154� - 164�
155 - 161
167 - 177
AS ABOVE
AS ABOVE
AS ABOVE
AS ABOVE
AS ABOVE
AS ABOVE
AS ABOVE
AS ABOVE
155�
AS ABOVE
AS ABOVE
AS ABOVE
AS ABOVE
155�
AS ABOVE156�
AS ABOVE
156�
AS ABOVE
AS ABOVE
AS ABOVE
AS ABOVE156�
11
LONGSERIES
SPEEDMETRES /
MINCOOLANT
SOLUBLE OIL
OR
SEMI-SYNTHETIC
OIL
25 - 30
15 - 20
10 - 15
15 - 24
10 - 15
4 - 8
12 - 16
6
5 - 10
15 - 25
7 - 11
25 - 35
15 - 30
25 - 30
4 - 6
Up to 45
30 - 35
40 - 100
40 - 50
30 - 36
15 - 20
25 - 30
< 20
FEEDCURVE
SeePage 14
H
F
H
H
C
E
F
C
K
C
L
L
M
L
-
SOLUBLE OIL
SOLUBLE OILEXTREME
PRESSURE
SOLUBLE OILEXTREME
PRESSUREOR
SULPHO-CHLORINATED
SOLUBLE OILEXTREME PRESSURE
ORSULPHO-CHLORINATED
SOLUBLE OILSULPHO-CHLORINATEDEXTREME PRESSURECHLORINATED OIL
DRY ORDETERGENT
WATER - SOLUBLEEMULSION
DRY OR
NEAT E.P. OIL
SOLUBLE OIL
(1 : 25)
LOW VISCOSITY
MINERAL OIL
SOLUBLE OIL
(1 : 20)
SOLUBLE OIL(1 : 20)
LIGHT MINERALOIL
DRY OR
SOLUBLE OIL
DRILL TECHNICAL DATA (cont.)
EXTRALENGTH
MORSETAPER
STANDARD
MORSETAPER
E/LENGTH
CODE TYPE � DENOTES RECOMMENDED
116 - 117
109� - 110�
118� - 119�
120� - 121
122 - 123
124 - 125
126
201 - 202
203 - 204
205 - 206
208�
241 - 242
244 - 245
251 - 252
254 - 255
AS ABOVE AS ABOVEAS ABOVE
261�279�
AS ABOVE
AS ABOVE AS ABOVEAS ABOVE
261�279�
AS ABOVE
AS ABOVE AS ABOVEAS ABOVE
261�279�
AS ABOVE
AS ABOVE AS ABOVE AS ABOVE AS ABOVE
AS ABOVE AS ABOVEAS ABOVE
261�279�
AS ABOVE
AS ABOVE AS ABOVE AS ABOVE AS ABOVE
AS ABOVE AS ABOVE AS ABOVE AS ABOVE
12
UD DRILL TECHNICAL DATA
Free Cutting steels
Structural steel. Case carburizing steel
Plain carbon steel
Alloy steel
Alloy steel.Hardened and tempered steel
Alloy steel. Hardened and tempered steel
Free machining Stainless steel
Austenit ic
Ferritic + Austenitic, Ferritic, Martensitic
Lamellar graphite
Lamellar graphite
Nodular graphite, Malleable Cast Iron
Nodular graphiteMalleable Cast Iron
Titanium, unalloyed
Titanium, alloyed
Titanium alloyed
Nickel, unalloyed
Nickel, alloyed
Nickel, alloyed
Copper
Beta Brass, Bronze
Alpha Brass
High strength Bronze
Al, Mg, unalloyed
Al alloyed Si < 0.5%
Al alloyed, Si > 0.5%< 10%
Al alloyed, Si > 10%Al-alloys, Mg-alloys
Thermoplastics
Thermosetting plastics
Reinforced plastic materials
MATERIAL TYPES HARDNESSHB
TENSILESTRENGTH
N/mm²
Ste
elS
tain
less
Ste
elC
ast I
ron
Tit
aniu
mN
icke
lC
op
per
Alu
min
ium
Mag
nes
ium
Syn
thet
icM
ater
ials
120
200
250
250
250350
350
250
250
300
150
150300
200
200300
200
270
270350
150
270
270350
100
200
200
470
100
150
120
120
-
-
-
400
700
850
850
8501200
1200
850
850
1000
500
5001000
700
7001000
700
900
9001200
500
900
9001200
350
700
700
1500
350
500
400
400
-
-
-
13
UD DRILL TECHNICAL DATA (cont.)
SURFACE SPEEDMETRES
PER MINUTE
FEEDCURVE
see Page 14
DRILL TYPE &SURFACE
TREATMENT
NORMALCHIP
FORM
extra long
middle/long
long
long
UDCTiN
15 - 2020 - 30
JL
long
long
middle
long
long
extra short
extra short
middle/short
middle/short
extra long
middle/short
middle/short
extra long
long
long
extra long
middle/short
long
short
extra long
middle
middle/short
short
extra long
short
extra short
UDLTiNUDLTiNUDL
TiN TiCN TiAlNUDL
TiN TiCN TiAlN
UDLTiN TiCN TiAlN
UDLTiN TiCN TiAlN
UDLTiN TiCN TiAlN
UDLTiN TiCN TiAlN
UDLTiN TiCN TiAlN
UDCTiAlNUDC
TiAlNUDC
TiAlN
UDCTiAlN
UDLTiCNUDSTiCNUDSTiCNUDL
TiCN TiAlNUDL
TiCN TiAlNUDL
TiCN TiAlNUDLTiNUDSTiNUDLTiNUDSTiNUDLTiNUDLTiN
UDSTiN
UDSTiN
UDLTiNUDSTiN
35 - 4550 - 7025 - 3540 - 5025 - 3035 - 4025 - 3035 - 40
15 - 2025 - 30
15 - 2020 - 2518 - 2127 - 328 - 10
12 - 1510 - 1516 - 2230 - 3545 - 5525 - 3035 - 4518 - 2125 - 35
12 - 1722 - 26
20 - 2530 - 3513 - 1720 - 25
5 - 67 - 11
12 - 1620 - 25
6 - 810 - 12
5 - 610 - 1255 - 6580 - 9560 - 70
90 - 10530 - 4045 - 5027 - 3340 - 5075 - 85
110 - 12565 - 75
100 - 115
55 - 6580 - 100
27 - 3340 - 50
75 - 85110 - 12555 - 65
80 - 100
HJHJGIGI
EG
EGEGKMEGGIGIEG
EG
EGEGCEGIGICELNLNLNKMNNNN
LN
KM
LNJL
14
DRILL FEEDS (mm / rev.)
FE
ED
/ R
EV
(m
m)
DRILL DIAMETER (mm)
HOW TO USE THE DRILL FEED CHART1. Locate Feed Curve (as given in the application data pages 11 & 13) on the right hand side of the drill feed chart.2. Locate Drill Diameter along bottom axis of chart.3. Determine point of intersection of Feed Curve and Drill Diameter.4. Project horizontally from point of intersection to left hand side of chart and read off nearest FEED / REV (mm).5. Select nearest feed on drilling machine within ± 20% of chart figure.
DRILL FEED CURVE CHART
15
General Drilling Feeds (mm per revolution)
DrillDiameter
Range (mm)
FeedRange
DrillDiameter
Range (mm)
FeedRange
1 - 33 - 55 - 8
8 - 1212 - 16
0.03 to 0.0750.05 to 0.180.10 to 0.280.15 to 0.350.20 to 0.45
16 - 2020 - 2525 - 3030 - 40Over 40
When setting to drill material of unknown machinability the slowestspeed and lightest feed should be used and these should be graduallyincreased until optimum output per regrind is obtained.
HELIX ANGLE OR SPIRAL
0.25 to 0.530.28 to 0.560.30 to 0.600.35 to 0.680.40 to 0.75
20°
30°
40°
SLOW SPIRAL
NORMAL SPIRAL
QUICK SPIRAL
16
PERIPHERAL SPEED
METRESPER MIN
5 10 20 30 40
DrillDia. mm
1.02.03.04.05.06.07.08.09.0
10.011.012.013.014.015.016.018.020.022.024.026.028.030.035.040.045.050.063.075.0100.0
15917955303983182652271991771591451331221141061008980736761575345403532252116
31821590106079563653045539835331828926524522721219917715914513312214410691807064504232
6364318221201590127210609107967066365785304904544243983543182902663442282121821601401281008464
95464770318023851908159013651194105995486779573568163659753147743539936634231827324021019215012696
1272863604240318025442120182015921412127211561060980908848796708636580532488456424364320280256200168128
Revolutions
17
TO rpm CONVERSION CHART
1591079505300397531802650227519901765159014451325122511351060995885795725665610570530455400350320250210160
50 70 80 90 10060
190929540636047703816318027302388211819081734159014701362127211941062954870798732684636546480420384300252192
222741113074205565445237103185278624712226202318551715158914841393123911131015931854798742637560490448350294224
2545612720848063605088424036403184282425442312212019601816169615921416127211601064976912848728640560512400336256
286381431095407155572447704095358231772862260123852205204319081791159314311305119710981026954819720630576450378288
31820159001060079506360530045503980353031802890265024502270212019901770159014501330122011401060910800700640500420320
per Minute
18
THE CORRECT USE OF DRILLS
A guide to successful drilling
• Make sure the workpiece is securely held and supported.Should it bend or move, it could cause the drill to break.
• Use a good socket and thoroughly clean both the socket andthe taper shank of the drill. Do not use steel objects to seatthe drill.
• Straight shank drill chucks must be able to hold the drillsecurely.
• Keep the drill sharp. Do not allow it to become blunt as it willrequire extra-grinding to get it sharp again.
• Direct an adequate supply of the recommended coolant tothe point of the drill. (see page 11).
• Do not allow chips to clog the drill flutes.• When re-sharpening take care to achieve the correct point
geometry (see page 22/24) and do not overheat the drillwhen grinding.
• Use core drills for enlarging existing holes - 2 flute drillsare not designed for this purpose.
• Use the correct drill to suit the application (see page 6-9).
Deep Hole Drilling
A general guide
A hole deeper than 3 times its diameter is considered a “deep hole”.Deep holes are successfully drilled by reducing speed and feed rates,as shown in the table on page 11. Care must be taken not to clogthe flutes with chips. In very deep holes it may be necessary towithdraw the drill frequently to clear the flutes. Extra length drillsshould be used with a guide bush as close to the workpiece aspossible to support the drill.
19
Recommended Speeds for Deep Holes
Depth of Hole % SpeedReduction
3 X Drill Diameter 10% 4 X Drill Diameter 20% 5 x Drill Diameter 30% More than 6 X Drill Diameter 40%
Recommended Feeds for Deep Holes
Depth of Hole % FeedReduction
3 to 4 X Drill Diameter 10% 5 to 8 X Drill Diameter 20%
Extra Length "Deep Hole" Drills (UDL Form)The SOMTA "Deep Hole" drill has a specially shaped flute form,commonly known as Parabolic, which gives rigidity for deep holedrilling and improves chip flow, enabling the full depth of the hole tobe drilled without withdrawal.These drills are of special robust design for use on tougher materialssuch as steels and cast irons with hardness up to 1000 N/mm².Similar drills for softer materials such as aluminium, mild steel etc.with hardness up to 500 N/mm² are available on special request.
Coolant Feed DrillsHigher production rates can be achieved when deep hole drilling byusing coolant feed drills.Harmful heat generation at the drill point is prevented by the supplyof coolant to the cutting face. This allows higher speeds and feedsand improved chip flow, thus eliminating the need to clear the flutesby withdrawal.
20
Core DrillingCore Drill Nomenclature
Core DrillsCutting Diameter Tolerance on Core Drills Core Drill Diameter (mm) Diameter Tolerance (mm) Above Up to Plus Minus - 6 + 0 - 0,018 6 10 + 0 - 0,022 10 18 + 0 - 0,027 18 30 + 0 - 0,033 30 50 + 0 - 0,039
OVERALL LENGTH
BODY
FLUTE LENGTH
RECESS SHANK
DIAMETER
HELIXANGLE
LAND
BODYCLEARANCEDIAMETER3 FLUTES
WEBLAND
4 FLUTES
BODYCLEARANCEDIAMETER
LIP CLEARANCEANGLE
CHAMFERLENGTH
LIPLENGTH
21
A Guide to Core DrillingCore drills are only used for enlarging diameters of existing holeswhether drilled, punched or cored. Having no point, the drill is onlyable to cut on the chamfer. The maximum amount of material thatcan be removed is restricted by the chamfer root diameter to 60% ofthe core drill diameter.Because of its multi-flute construction the core drill gives better holesize and surface finish than a two flute drill. Two flute drills shouldnot be used to enlarge existing holes as they will tend to chip andbreak.Speed and Feed rates for Core DrillsSpeed - As for 2 flute drillsFeed - 3 Flute 1 to 1,5 X 2 flute drill feed rate 4 Flute 1,5 to 2 X 2 flute drill feed rate
Cutting diameter toleranceSOMTA Twist Drills are manufactured to h8 tolerance.2 Flute Drills
Cutting Diameter Tolerance on Twist Drills Drill Diameter (mm) Diameter Tolerance (mm) Above Up to Plus Minus - 3 + 0 -0,014 3 6 + 0 -0,018 6 10 + 0 -0,022 10 18 + 0 -0,027 18 30 + 0 -0,033 30 50 + 0 -0,039 50 80 + 0 -0,046
Back Taper on Fluted PortionThe drill diameter is normally reduced over the fluted portion toprevent jamming. The amount of back taper is a maximum of: 0,08mm on diameter per 100 mm length.
Back taper is usually only applied to sizes over 6 mm.
22
118°
125° - 135°
90°
125° - 135°
135°
140° - 145°
118°
125° - 135°
70°
DRILL POINT STYLES
Standard Point
This point is suitable for general purpose drilling.
Split Point
The split point minimises end thrust and is self centering.
Long Point
Used for wood, plastic, hard rubber, fibres etc.
Cast Iron Point ("DX" Point)
The secondary angle reduces wear on the outer corners.
23
125° - 135°
125° - 135°
125° - 135°
118°
135°
130° 10% D
Heavy Duty Notched Point
The notched point reduces end thrust and optimises centre cuttingefficiency with chisel strength. It is recommended for hard and highstrength materials.
Web Thinned Point
The web thinned point reduces end thrust and improves centre cuttingefficiency.
"UX" Point
The 130° special notched "UX" point style provides self centering,easier penetration, improved hole accuracy and improved loaddistribution. This special notch geometry gives a corrected rake angleof 15° which provides strong point for harder materials, as well aspreventing snatching with materials such as Aluminium, Brass,Bronze and Plastics. Available on UDL and UDS drills.
24
Part Split Point
The 130° part split point is similar to the conventional split point. Thepart split point has a wider chisel edge. Provides easy penetration,self centering and optimises centre cutting efficiency with chiselstrength.
Common Re-Sharpening Errors on Standard Drill Points
130°
140° - 145°
LIPCLEARANCEANGLETOO GREAT
LIPCLEARANCEANGLETOO SMALL
CHISEL ANGLETOO GREAT
CHISEL ANGLETOO SMALL
25
DIFFERENCE INRELATIVE LIP HEIGHTWILL DRILL AN OVERSIZEHOLE.
UNEVEN WEBTHINNING
WEB THINNINGTOO GREAT
Web thinning is recommended for:
1. restoring chisel edge to the original length after severalregrinds.
2. larger drills where the machine thrust is limited.3. difficult materials.
Lip Clearance Angle
Drill Size (mm) Angle (°)Up to 3 18 - 243.1 - 6 14 - 186.1 - 12 10 - 1412.1 - 20 8 - 12Above 20 6 - 10
LIPS UNEQUAL LENGTH(DIFFERENCE IN RELATIVELIP HEIGHT.)
26
DRILLING PROBLEMS: CAUSES AND SOLUTIONSBroken or Twisted Tangs(a) Possible Cause
Bad fit between the drill sleeve and the shank of the drill.Solution(i) Use only sleeves which are in good condition (avoid
worn or damaged sleeves).(ii) Ensure the drill shank and sleeve are thoroughly clean.
Note:The tang is not intended to transmit the drive - it is only used forejection. The Morse Taper is self-holding and relies on a good fit inthe sleeve to transmit the drive.
Drill Web Split(a) Possible Cause
The feed is too great.SolutionUse the correct feed for the drill size material - see page 14.
(b) Possible CauseInsufficient lip clearance behind the cutting edge.SolutionCheck that the lip clearance is as per information on page 24/25.
(c) Possible CauseExcessive web thinning.SolutionThe web thickness should not be less than 10% of the drilldiameter.
(d) Possible CauseUsing a hard object to seat the drill in the sleeve.SolutionUse soft material e.g. copper or wood, to seat the drill.
Worn outer Corners(a) Possible Cause
The peripheral speed is too high for the material being drilled.SolutionUse the recommended speed - see page 11.
27
Broken outer Corners(a) Possible Cause
Drilling thin material particularly when not properly supported.SolutionUse a sheet metal drill and clamp the workpiece securely.
(b) Possible CauseUsing a 2 flute drill to enlarge the diameter of an existing hole.SolutionOnly core drills should be used for this purpose.
Chipped or Broken Lips(a) Possible Cause
This is usually caused by excessive lip clearance angles behindthe cutting edge.SolutionCheck that the lip clearance is as per information on page 24/25.
Oversized and Out of Round Holes(a) Possible Cause
Unequal point angles.SolutionThis usually results when hand grinding the point. Use a pointgrinding fixture or machine.
(b) Possible CauseUnequal cutting edge length (lip height).SolutionWhen re-grinding ensure that the same amount of material isremoved from both flanks.
(c) Possible CauseLoose spindle or worn drill sleeve.SolutionUse equipment which is in good condition.
(d) Possible CauseThe workpiece moves.SolutionThe workpiece must be securely clamped.
28
Drill rubbing and not cutting(a) Possible Cause
Too little lip clearance behind the cutting edge.SolutionCheck that the lip clearance is as per information on page 24/25.
Cracks in cutting edges(a) Possible Cause
The point is overheated and cooled too quickly when re-sharpening.SolutionUse coolant when grinding or grind in stages, quenchingfrequently in soluble oil.
Rough hole finish(a) Possible Cause
The drill is blunt.SolutionRe-sharpen as per information on page 24/25.
(b) Possible CauseInadequate supply of coolant to the point.SolutionThe coolant must reach the point of the drill.
Drill breaks at flute runout(a) Possible Cause
The workpiece moves during drilling.SolutionThe workpiece must be securely clamped.
(b) Possible CauseThe flutes are clogged with swarf.SolutionClear the flutes by frequently withdrawing the drill, or use a drillmore suited to the material e.g. a UDL drill for aluminium.
(c) Possible CauseUsing the wrong type of drill e.g. using a jobber drill for thinmaterial.SolutionSee pages 6 to 9 for the correct drill to suit the application.
29
CENTRE DRILLS
CENTRE DRILL NOMENCLATURE
OVERALL LENGTH
FLUTELENGTH
PILOTLENGTH
60°118°
60° 120°
TYPE 'B'
TYPE 'R'
RADIUS
PILOTDIAMETER
BODY DIAMETER
TYPE 'A'
30
SELECTING THE CORRECT CENTRE DRILL
TYPE "A"
For general centering operations on workpieces requiring additionalmaching between centres.
TYPE "B" (Protected Centre)Sometimes called Bell Type
The 60° cone surface produced by this centre drill is recessed belowthe surface of the workpiece and is therefore protected from damage.
TYPE "R" (Radius)
The type "R" centre drill is also used for general centering operations,but produces a radius centre suitable for a variety of male centreangles eg. 60°, 82° or 120° can be used as an alternative to type "A"above.
31
THE CORRECT USE OF CENTRE DRILLS
A guide to successful drilling
Recommended SpeedsThe peripheral speeds for centre drills are the same as for 2 flutedrills given on page 10-11. For calculation purposes the nominaldiameter given below should be used.
Centre Drill Nominal Centre Drill Nominal Size Diameter (mm) Size (mm) Diameter (mm) BS 1 2 1 2 BS 2 3 1.25 2 BS 3 4 1.6 3 BS 4 6 2 4 BS 5 8 2.5 5 BS 6 11 3.15 6 BS 7 14 4 7
5 9 6.3 11 8 14 10 18
Recommended FeedsUse the nominal diameter given above to establish the feed as givenon page 19, and then reduce by 40% for centre drills.
Re-sharpening of Centre DrillsCentre Drill can be re-sharpened on the point only. refer to there-sharpening guide for 2 flute drill on page 24/25.
32
SHANK DIAMETER
SHANK
LENGTH
PILOT
PILOT DIAMETER
RECESS
BODY
BODY DIAMETER
COUNTERBORES
COUNTERBORE NOMENCLATURE
A General GuideCounterbores are used to create seatings for cap screw heads andare therefore identified by the cap screw they suit. They are availablewith straight or Morse Taper shanks.
33
Cap Screw Pilot Drill Counterbore Size Size (mm) Diameter (mm) M 3 3.4 6 M 3.5 3.9 6.5 M 4 4.5 8 M 5 5.5 10 M 6 6.6 11 M 8 9 15 M 10 11 18 M 12 14 20
Speeds & FeedsThe speeds and feeds for counterbores are approximately 80% to85% of those for drills as given on page 11.The counterbore diameter given in the above table is used for thiscalculation.
RE-SHARPENINGCounterbores are re-sharpened only by grinding the front cuttingedges, maintaining the original relief angle of 6°- 8°.
34
OVERALL LENGTH
CUTTINGANGLE
BODYDIAMETER
MINIMUM CUTTINGDIAMETER
BODY DIAMETER
CUTTINGANGLE
MINIMUM CUTTINGDIAMETER
BODY DIAMETER
OVERALL LENGTH
COUNTERSINKS
COUNTERSINKS NOMENCLATURE
THE CORRECT USE OF COUNTERSINKSA General GuideCountersinks are normally used to produce a 60° or 90° chamferrecess which accommodates the corresponding 60° or 90° screwhead. They are available in straight or Morse Taper Shank.
Speeds and FeedsThe speeds and feeds for countersinks are the same as those fordrills (see page 11) and are based on the diameter midwaybetween the largest and smallest diameter of the countersink.
RE-SHARPENINGThe axial relief is critical to the performance of the countersink andshould not be altered. When re-sharpening, grind only the flute face.
35
REAMERS
REAMER NOMENCLATURE
SECTION A-A
NO CIRCULARLAND
BEVEL LEADANGLE
TAPER LEAD
B
B
A
A
TAPER LEADANGLE
SHANK
SQUARE
SIZE OFSQUARE
DIA
ME
TE
R
OVERALL LENGTH
CUTTING LENGTH RECESS SHANK
B
B
DIA
ME
TE
R
PRIMARYCLEARANCEANGLE
CLEARANCEANGLE
CIRCULARLAND
SECTION B-B
CIRCULARLAND
CLEARANCEANGLE
FLUTE
CENTRE HOLE
RADIAL FACECUTTING EDGE
36
SELECTING THE CORRECT REAMERStandard Reamers
Parallel Hand Reamers
General hand reaming.
MTS Parallel Machine Reamers
General machine reaming.
Machine Chucking Reamers, Parallel Shank
General machine reaming for deeper holes.
MTS Machine Chucking Reamers
General machine reaming for deeper holes.
MTS Taper Bridge Machine Reamers
For opening out existing holes for alignment on structural steel work.
Intermediate size reamers are available on request.
37
Reamers for specific Applications
Hand Taper Pin Reamers - Metric
For reaming holes to suit standard metric taper pins with a taper of1:50.
Hand Taper Pin Reamers - Fractional
For reaming holes to suit standard fractional taper pins with a taperof 1:48.
MTS Taper Socket Finishing Reamers
Finishing of Morse Taper holes.
MTS Taper Socket Roughing Reamers
Rough reaming Morse Taper holes.
Machine Chucking Reamers, Parallel ShankTungsten Carbide Tip
Reaming of difficult to machine materials or mass production.
38
THE CORRECT USE OF REAMERS
A guide to successful reaming• Make sure the workpiece is securely held and supported.
Should it bend or move, it could result in a poor finish orcause the reamer to break.
• Use a good morse taper sleeve and thoroughly clean both thesleeve and the taper shank of the reamer.
• As a reamer only cuts on the bevel lead and not on theperipheral land, it is essential to keep it sharp. A bluntreamer wears on the outer corners on the bevel lead,resulting in a poor fininsh, undersize holes and increasedtorque. (See page 39 for re-sharpening details.)
• Direct an adequate supply of the recommended lubricant tothe cutting area. When reaming high tensile materials, animproved surface finish can be achieved by usingchlorinated or sulphurised oils.
Stock RemovalReamers are used to produce accurate holes with a good surfacefinish. It is a common fault to leave too little stock for removal byreaming. This results in a rubbing action and excessive wear of thereamer. The table below shows approximate amounts of stock to beremoved by reaming.
Machine Reamers
Above
1.5361325
Up to1.536
1325
Pre-Drilled(mm)
Pre-CoreDrilled(mm)
Size of ReamedHole (mm)
0.30.30.30.40.50.5
0.20.20.20.250.30.3
Hand ReamersThe hand reaming allowance should be approximately two thirds ofthe machine reaming allowance.
39
RE-SHARPENINGA reamer is only sharpened on the bevel lead which performs thecutting action. This operation must be done only by skilled operatorson appropriate machine tools.When re-sharpening it is essential to maintain both the original reliefangle of 6°- 8° and the concentricity of the bevel lead.
* Feed Conversion Table
Reamer DiameterRange (mm)
Feed (mm/rev)
Above
1.5361325
Up to1.5361324
Light (L)0.005 - 0.0250.025 - 0.05
0.05 - 0.10.1 - 0.150.15 - 0.250.25 - 0.5
Medium (M)0.012 - 0.05
0.05 - 0.10.1 - 0.15
0.15 - 0.250.25 - 0.5
0.5 - 1
Heavy (H)0.025 - 0.0750.075 - 0.150.15 - 0.250.25 - 0.380.38 - 0.760.76 - 1.27
Tolerances
Somta reamers are manufactured to produce holes to H7 tolerance.The tolerance limits shown in the table below are added to the nominalreamer diameter.eg. nominal diameter = 12mm actual diameter = 12.008mm/12.015mmTolerance limits for reamers and hole sizes produced.
Reamer DiameterRange (mm)
Cutting DiameterTolerance
Above136101830
Up to3610183050
mm+0.004 +0.008+0.005 +0.010+0.006 +0.012+0.008 +0.015+0.009 +0.017+0.012 +0.021
mm0 +0.0100 +0.0120 +0.0150 +0.0180 +0.0210 +0.025
Hole DiameterTolerance H7
Other useful tolerances can be found on page 121.
40
†Speedm/min
*Typeof
FeedTYPE GRADE
CARBONSTEEL
&
ALLOYSTEEL
FREE CUTTING
0.3 to 0.4% Carbon
0.3 to 0.4% Carbon
0.4 to 0.7% Carbon
0.4 to 0.7% Carbon
HARDNESS
BRINELL
TONS PER
SQ IN.(MAX)
N/mm²(MAX)
150
170
248
206
286
35
40
59
47
67
525
600
900
700
1000
248
330
380
59
75
87
900
1125
1300
STAINLESSSTEEL
MartensiticFree Cutting
MartensiticStd. Grade
AusteniticFree Cutting
Austenitic Std. Grade
12-15
7-10
5-8
M-H
M
L
7-10
5-8
2-4
5-8
2-5
M
L-M
5-8
2-5
L-M
L-M
As Supplied
380 54 810
TITANIUM
Titanium Comm: Pure
Titanium Comm: Pure
Titanium Comm: Pure
Titanium Alloyed
Titanium Alloyed
NIMONICALLOYS
Wrought
Cast
300
350
67
78
1000
12002-5 L
170
200
275
340
380
40
43
65
76
85
600
650
975
1140
1275
7-10 M
2-4 L-M
TOOLSTEEL
HSS Standard
Grades
HSS Cobalt Grades
Hot Working Steel
Cold Working Steel
225
225
48
54
720
800
7-10 M
REAMER TECHNICAL DATA
† See Speed Conversion Chart on page 16/17. cont on page 41* See table on page 39.
M
M
L
TYPICAL PHYSICALPROPERTIES
41
REAMER TECHNICAL DATA
† See Speed Conversion Chart on page 16/17.* See table on page 39.
†Speedm/min
*Typeof
FeedTYPE GRADE
CAST IRONS
Grey
Ductile
Maleable
Hardened & Tempered
HARDNESS
BRINELL
N/mm²(MAX)
MANGANESESTEEL
250
330
52
74
780
1100
As Supplied
COPPERALLOYS
12-15
10-13
12-15
4-5
2-3
20-35
30-45
15-30
10-15
15-45
7-15
H
H
H
M
M-H
M
As Supplied
Brass Free Cutting
Brass Low Leaded
Bronze Silicon
Bronze Manganese
CopperBronze AluminiumBronze CommercialBronze Phospor
12-15 M-HPLASTICS
Soft
Hard
Reinforced
M-H
M-H
M-H
M
L
ALUMINIUMALLOYS
As Supplied 30-45 H
MANGANESEALLOYS
As Supplied 35-60 H
ZINCALLOYS
As Supplied 30-45 H
As Supplied
TYPICAL PHYSICALPROPERTIES
TONS PER
SQ IN.(MAX)
42
REAMING PROBLEMS: CAUSES AND SOLUTIONSPoor Surface Finish(a) Possible Cause
Incorrect speed and/or feed.SolutionUse the recommended speed/feed - see page 40/41.
(b) Possible CauseA Worn reamerSolutionDo not allow the reamer to become too blunt. See page 39for re-sharpening details.
(c) Possible CauseInsufficient or wrong type of lubricant.Apply and adequate supply of the correct lubricant to thecutting area.See the drill table on page 11 for the recommended lubricants.
(d) Possible CauseDamaged cutting edges.SolutionUse a reamer which is in good condition.
Reamer Chattering(a) Possible Cause
Lack of rigidity in set up.SolutionOnly use equipment which is in good condition and make surethe workpiece is securely held.
(b) Possible CauseFeed too low.SolutionUse the recommended speed/feed - see page 40/41.
Reamer showing rapid wear(a) Possible Cause
Too little stock in the hole for reaming causing the reamer torub and not cut.SolutionSee page 38 for recommended stock removal.
43
(b) Possible CauseSpeed too high or feed too low.SolutionUse the recommended speed/feed - see page 40/41.
(c) Possible CauseThe workpiece material is too hard.SolutionUse a HSS-Co reamer.
Tapered or Bell-Mouthed holes(a) Possible Cause
Mis-alignment of the reamer and the hole.SolutionAlign the reamer and the hole.
(b) Possible CauseThe machine spindle and/or bearings are worn.SolutionOnly use equipment which is in good condition.
Reamer rubbing and not cutting(a) Possible Cause
Too little reaming allowance in the hole.SolutionSee table of stock removal on page 38.
(b) Possible CauseReamer re-sharpened with too little or no relief on the bevellead.SolutionRe-grind the bevel lead to a 6°- 8° relief.
Oversized holes(a) Possible Cause
Excessive run-out on the machine spindle or holding deviceeg. taper sleeve, collet or chuck.SolutionOnly use equipment which is in good conditon.
44
TAPS
TAP NOMENCLATURE
SIZE OF SQUAREACROSS FLATS
SECTION B-B
BB
FLA
T L
EN
GT
H
AA
n
LEADANGLE
NOMINALDIAMETER
ROOTDIAMETER
TH
RE
AD
LE
NG
TH
CH
AM
FE
R L
EA
D
n = No. OF THREADSPER INCH.
p = PITCH
LAND
FLUTE CUTTINGFACE
WEBTHICKNESS
SECTION A-A
SHANKDIAMETER
p
OV
ER
ALL
LE
NG
TH
45
Abbreviations for standard thread forms
BA - British Association
BSB - British Standard Brass
BSP - British Standard Pipe (Fine) "G" Series
BSPT - British Standard Pipe Taper (Rc Series)
BSW - British Standard Whitworth
BSF - British Standard Fine
M - Metric
MF - Metric Fine
NPS - National Pipe Straight
NPT - National Pipe Taper
UNC - Unified National Coarse
UNF - Unified National Fine
UNEF - Unified Extra Fine
46
WHITWORTH
H = 0.866Ph = 0.708Pr = 0.1443P
ISO METRIC
THREAD FORMS
60°
p
H hr
r
55°
p
H = 0.960491Ph = 0.640327Pr = 0.137329P
H h
47
UNIFIED
H = 0.86603P5/8H = 0.54127P
1/4H = 0.21651P1/8H = 0.10825P
BA
H = 1.1363365Ph = 0.6Ps = 0.26817Pr = 0.18083P
1/4H
p
1/8H60°
5/8H
p
s47-½°
H
s
h
r
48
H = 0.960237Ph = 0.640327Pr = 0.137278P
BSPT
d = MAJOR DIAMETER AT GAUGE PLANE d1 = MINOR DIAMETER AT GAUGE PLANETAPER = 1 IN 16 ON DIAMETER
BSB
H = 0.86603Ph = 0.5237Pr = 0.1667P
55°
P
90°d1
H hr
d
P
55°
rhH
49
H = 0.866Ph = 0.8Pf = 0.033P
H = 0.866Ph = 0.8Pf = 0.033P
NPT
d = MAJOR DIAMETER AT GAUGE PLANE d1 = MINOR DIAMETER AT GAUGE PLANETAPER = 1 IN 16 ON DIAMETER
Pf
NPS
f
hH
60°
P
90°d1
f
60°f
H hd
50
ACME
h = 0.5P + CLEARANCEF = 0.3707PFc = 0.3707P - (0.256 X MAJOR DIAMETER ALLOWANCE)
TRAPEZOIDAL
h = 0.5P + CLEARANCE
Fc
29°
F P
h
30°
h
1/2P
P
51
SELECTING THE CORRECT TAPShort Machine and Hand Taps
For general purpose hand or machine use for short production runs.Best suited for materials which do not present chip disposal problems.
Machine Taps
Spiral Point Tap
Sometimes called a gun nosed tap. For machine use on throughholes. Suitable for a wide range of materials. The gun nose createschip disposal ahead of the tap while the flute geometry allows anadequate supply of lubricant to the cutting area, making higher tappingspeed possible.
Spiral Flute Tap
Mainly for work in blind holes and on ductile materials, such asaluminium and zinc alloys, which produce long stringy chips. Thetaps have a 35° right hand helix. The flute shape eliminates cloggingand jamming, resulting in improved tap life.
Taper
Second
Bottoming
52
Colour Band Application Taps (CBA)
The primary benefit of the CBA range is enhanced threadingperformance due to geometry designed for specific materialapplication groups. The result is an improved quality of finish and anincreased number of holes per tap, giving extended tap life andreduced cost per hole. Manufactured from HSS-EV steel (HighVanadium) for greater wear resistance.
Red Band
Designed for high tensile materials such as Tool Steels, HeatTreatable Steels, Spring Steel, Case Hardening Steel, UnalloyedTitanium, Nitriding Steel, Cold Drawn Constructional Steel and HighTensile Steel.Used to tap materials with hardness up to 470HB,tensile strength up to 1500N/mm². Spiral flute taps have 15° righthand helix which efficiently forces high tensile material swarf up outof the hole, while still maintaining correct cutting geometry. The redband tap is supplied as standard with TiAlN coating.
Blue Band
Designed for tough materials, such as Stainless Steel, TitaniumAlloys, Cast Steel, Heat Resisting Steel and Work Hardening Steel.Used to tap materials with hardness up to 350HB, tensile strengthup to 1250N/mm². Truncated thread after lead reduces frictionalcontact with the threaded hole and allows easier penetration ofcoolant. Spiral flute taps have 40° right hand helix allowing toughmaterial swarf to be efficiently removed from the hole. Supplied asstandard with TiAlN coating.
53
Colour Band Application Taps (CBA)
Yellow Band
Designed for more ductile materials such as Aluminium, MagnesiumAlloys, Soft Brass (MS58), Plastics, Zinc Alloys and Copper. Usedto tap materials with hardness up to 250HB, tensile strength up to900N/mm². Wide flutes allow more efficient swarf removal whichprevents clogging and excessive torque. High rake angle improvesshear characteristic and reduces build-up on the cutting edge,allowing tap to cut more freely for longer periods. Spiral flute tapshave 40° right hand helix, allowing ductile material swarf to beefficiently forced out of the hole. The yellow band tap is supplied asstandard in bright condition.
White Band
Designed for highly abrasive materials such as Cast Iron andreinforced plastics. Used to tap materials with hardness up to 300HBtensile strength up to 1000N/mm². Increased number of flutesreduces torque and increases tap life. Taps have 15° right handhelix. The white band tap is TiAlN coated as standard.
Fluteless Taps
For machine use on through or blind holes. Best suited for ductilematerials, such as aluminium and zinc alloys as the threads are coldformed, not cut like a conventional tap. For slightly tougher materialsfluteless taps in the range of 5mm to 12mm can be supplied with agash.
54
Serial Taps
For general purpose machine or hand use in tough materials,producing accurate threads with a high finish. Used in sequence toremove most of the material in stages before finally sizing with theFinishing tap.
Pipe Taps
For machine use on pipe work for parallel threads.
For machine use on pipe work for tapered threads.
Special taps are available on request.
Rougher
Intermediate
Finisher
55
RECOMMENDED TAPPING DRILL SIZES(For 75% thread depth)
Metric Coarse
Size Pitch0.40.450.50.60.70.750.8111.251.251.51.51.75222.52.52.5333.53.53.5444.54.5555.5
TappingDrill Size (mm)
*Fluteless Tapping Drill Sizes
22.533.544.5567891011121416182022242730323336394245485256
1.6 (1.8)*2.052.5 (2.75)*2.9 (3.2)*3.3 (3.65)*3.7 (4.1)*4.2 (4.6)*5 (5.5)*66.8 (7.4)*7.88.5 (9.25)*9.510.2 (11.1)*121415.517.519.5212426.530.529.5323537.540.5434750.5
56
Metric Fine
SizeTapping
Drill Size (mm)Pitch22.533.544.556788910101212141416161818202022222424252527303032333636
0.250.350.350.350.50.50.50.750.750.751111.251.251.51.251.51.01.51.52.01.521.521.521.5221.521.51.51.52.0
1.752.152.653.153.544.55.256.257.27898.7510.7510.512.7512.51514.516.51618.51820.52022.52223.5232528.52830.531.534.534
57
Metric Fine (cont)
SizeTapping
Drill Size (mm)Pitch39404245485052
1.51.51.51.51.51.51.5
37.538.540.543.546.548.550.5
BSWNominalDiameter
TappingDrill Size (mm)TPI
3/321/8
5/323/167/321/4
5/163/8
7/161/2
9/165/83/47/81"
1-1/81-1/41-1/21-3/4
2"
48403224242018161412121110987765
4-1/2
1.92.553.23.74.55.16.58
9.310.512.213.516.519.5222528343945
BSF3/167/321/45/16
32282622
44.75.46.8
58
BSFNominalDiameter
TappingDrill Size (mm)TPI
3/87/161/2
9/165/83/47/81"
1-1/81-1/41-1/2
2018161614121110998
8.39.811
12.714
16.519.522.525.529
34.5
UNCNo.3No.4No.5No.6No.8No.10No.12
1/45/163/8
7/161/2
9/165/83/47/81"
1-1/81-1/41-3/81-1/21-3/4
2"
4840403232242420181614131211109877665
4-1/2
22.252.62.753.43.84.45.16.68
9.410.812.213.516.519.522252831343945
59
UNFNominalDiameter
TappingDrill Size (mm)TPI
No.3No.4No.5No.6No.8
No.10No.123/161/4
5/163/8
7/161/2
9/165/83/47/81"
1-1/81-1/41-3/81-1/2
56484440363228322824242020181816141212121212
2.12.352.652.93.54.14.64
5.56.98.59.811.512.814.517.520.523.526.529.532.536
BA0123456789
10
25.428.231.334.838.343.147.952.959.165.172.6
5.14.53.93.43
2.652.3
2.051.8
1.551.4
60
BSPNominalDiameter
TappingDrill Size (mm)TPI
1/81/43/81/25/83/47/81"
1-1/41-1/21-3/4
2"
281919141414141111111111
8.811.815.51921
24.528.53140
45.551.557
BSPT1/81/43/81/23/41"
1-1/41-1/2
2"
281919141411111111
8.611.515.018.524.0
30.2539.045.056.5
NPS1/81/43/81/23/41"
1-1/41-1/2
2"
2718181414
11-1/211-1/211-1/211-1/2
9.112.015.519.024.530.539.445.557.5
61
NPTNominalDiameter
TappingDrill Size (mm)TPI
1/81/43/81/23/41"
1-1/41-1/2
2"
2718181414
11-1/211-1/211-1/211-1/2
8.411.0
14.2517.523.029.037.543.555.5
Fluteless TapsFluteless taps are used for cold forming threads in ductile materialsand have the following advantages.
(a) Increased strength and tap life resulting from:(i) Elimination of flutes which reduce the shear strength of
the tap.(ii) The lack of cutting edges which, in a conventional tap,
wear and break down.(iii) The lack of chips, which sometimes causes jamming.
(b) Better blind hole tapping due to the lack of chips and problemsrelating to chip removal.
(c) Higher productivity due to faster tapping speeds.(d) Stronger threads.
The grain fibres of the metal are not cut, but displaced, to form thethreads, which are stronger than cut threads. It is accepted that a60% cold formed thread is as strong as a 75% cut thread.
FLUTELESS TAP
STRONGER THREAD
GRAIN FIBRE OFMETAL UNBROKENBURNISHED THREAD
NO CHIPS
62
TYPE GRADE
CARBONSTEEL
FREE CUTTING
0.3 to 0.4% Carbon
0.3 to 0.4% Carbon
0.4 to 0.7% Carbon
0.4 to 0.7% Carbon
HARDNESS
BRINELL
TONS PER
SQ IN.N/mm²
ALLOYSTEEL
150
170
248
206
286
33
38
54
44
63
500
570
800
650
950
248
330
380
54
74
82
810
1100
1250
STAINLESSSTEEL
Martensitic Free CuttingMartensitic Std. GradeAustenitic Free CuttingAustenitic Std. Grade
TYPICAL PHYSICALPROPERTIES
As Supplied
248 54 810
TITANIUM
Titanium Comm: Pure
Titanium Comm: Pure
Titanium Comm: Pure
Titanium Alloyed
Titanium Alloyed
NIMONICALLOYS
Wrought
Cast
300
350
67
78
1000
1170
170
200
275
340
380
38
43
65
76
85
570
650
975
1140
1275
TOOL STEEL
HSS Standard
Grades
HSS Cobalt Grades
Hot Working Steel
Cold Working Steel
225
225
48
54
720
810
TAP TECHNICAL DATA
MANGANESESTEEL
As Supplied
Tough
Hard
63
*TAPPERIPHERAL
SPEEDm/min
THROUGHHOLE
RECOMMENDEDTAP TYPE
* The tapping speeds for fluteless taps are 2-3 times higher cont on page 64 than the recommended speeds given.
BLINDHOLE
ALTERNATIVETAP TYPE
THROUGHHOLE
BLINDHOLE
LUBRICANTS
Sp/Point Sp/Flute Str/Flute Str/Flute
8-10
8-12
10-15
Sulphur
based oil
Sp/Point Sp/Flute Str/Flute Str/Flute 8-12Sulphur
based oil
Sp/Point Sp/Flute Str/Flute Str/Flute 2-6
Heavy duty
Sulphur
based oil
See CBA Tap section pages 66 & 67. 2-4Chlorinated
oil
2-4Chlorinated
oil
Sp/Point Sp/Flute Str/Flute Str/Flute 8-10Sulphur
based oil
Sp/Point Str/Flute Str/Flute - 15-20Sulphur
based oil
TAP TECHNICAL DATA (cont.)
See CBA Tap section pages 66 & 67.
64
TYPE GRADE HARDNESS
BRINELL
TONS PER
SQ IN.N/mm²
ALUMINIUMALLOYS
240
330
52
74
780
1110
COPPERALLOYS
Brass Free Cutting
Brass Low Lead
Bronze Silicon
Bronze Manganese
Copper Free Machining
Copper Electrolytic
Bronze Aluminium
Bronze Commercial
Bronze Phosphor
TYPICAL PHYSICALPROPERTIES
As Supplied
PLASTICS
TAP TECHNICAL DATA
CASTIRONS
Grey
Ductile
Maleable
Hardened & Tempered
Long ChipShort Chip
As Supplied
MANGANESEALLOYS
As Supplied
ZINCALLOYS
As Supplied
Soft
HardReinforced
As Supplied
65
*TAPPERIPHERAL
SPEEDm/min
THROUGHHOLE
RECOMMENDEDTAP TYPE
* The tapping speeds for fluteless taps are 2-3 times higher than the recommended speedsgiven.
BLINDHOLE
ALTERNATIVETAP TYPE
THROUGHHOLE
BLINDHOLE
LUBRICANTS
Str/Flute Str/Flute Sp/Point -
4 -8
5-10 Dry soluble oilor paraffin
Fluteless Fluteless Sp/Point Sp/Flute20-25
10-15
Sol. oil orlight material
oil
Sol. oil orlight mineral oil
Chlorinatedoil or soluble oil
Sp/Point Sp/Flute Str/Flute Str/Flute 15-20 Sul. B Oil
Fluteless Fluteless Str/Flute Str/Flute 15-20 Soluble Oil
Fluteless
Sp/Point
Fluteless
Sp/Point
Fluteless
Str/Flute
Fluteless
Str/Flute
Str/Flute
Str/Flute
Sp/Point
Str/Flute
Str/Flute
Str/Flute
Sp/Point
Str/Flute
15-20
25-30
10-12
3-5
15-20
8-12
10-12
3-5
3-5Sol. oil or
light mineral oil
Str/Flute Str/Flute Sp/Point - Dry4-7
12-15
TAP TECHNICAL DATA (cont.)
For optimum performance for machine tapping see Colour Band Application (CBA)section pages 66 & 67.
66
CBA TAP TECHNICAL DATA
Free Cutting steels
Structural steel. Case carburizing steel
Plain carbon steel
Alloy steel
Alloy steel.Hardened and tempered steel
Alloy steel. Hardened and tempered steel
Free machining Stainless steel
Austenit ic
Ferritic + Austenitic, Ferritic, Martensitic
Lamellar graphite
Lamellar graphite
Nodular graphite, Malleable Cast Iron
Nodular graphiteMalleable Cast Iron
Titanium, unalloyed
Titanium, alloyed
Titanium alloyed
Nickel, unalloyed
Nickel, alloyed
Nickel, alloyed
Copper
Beta Brass, Bronze
Alpha Brass
High strength Bronze
Al, Mg, unalloyed
Al alloyed Si < 0.5%
Al alloyed, Si > 0.5%< 10%
Al alloyed, Si > 10%Al-alloys, Mg-alloys
Thermoplastics
Thermosetting plastics
Reinforced plastic materials
MATERIAL TYPES HARDNESSHB
TENSILESTRENGTH
N/mm²
Ste
elS
tain
less
Ste
elC
ast I
ron
Tita
nium
Nic
kel
Cop
per
Alu
min
ium
Mag
nesi
umS
ynth
etic
Mat
eria
ls
120
200
250
250
250350
350
250
250
300
150
150300
200
200300
200
270
270350
150
270
270350
100
200
200
470
100
150
120
120
-
-
-
400
700
850
850
8501200
1200
850
850
1000
500
5001000
700
7001000
700
900
9001200
500
900
9001200
350
700
700
1500
350
500
400
400
-
-
-
Surface Treatment (Coating) TiN, TiCN, TiAIN coatings are available on request
67
RECOMMENDED TAP TYPE
CBA TAP TECHNICAL DATA (cont.)
NORMALCHIPFORM
Recommended X SuitableSPEED M/Min
STANDARD COATED WHITEBAND
YELLOWBAND
BLUEBAND
REDBAND
extra long
middle/long
long
long
long
long
middle
long
long
extra short
extra short
middle/short
middle/short
extra long
middle/short
middle/short
extra long
long
long
extra long
middle/short
long
short
extra long
middle
middle/short
short
extra long
short
extra short
12
12
10
10
8
5
9
6
5
11
8
11
8
8
9
6
9
18 - 27
18 - 27
18 - 24
18 - 24
9 - 15
9 - 15
18 - 24
9 - 15
8 - 15
18 - 27
9 - 18
18 - 27
9 - 18
9 - 15
12 - 18
6 - 12
12 - 18
5
4
11
30
18
5
15
6 - 12
5 - 11
15 - 24
43 - 55
40 - 49
6 - 12
24 - 30
30
18
15
27
11
8
43 - 52
30 - 36
24 - 30
-
15 - 21
9 - 15
X
X
X
X
X
X
X
X
X
X
X
X
68
Metres / Min 4 6 8 9 10 12
Tap Size
mm Inch
1.61.82
2.22.53
3.54
4.5567891011121314161820222427303336394245485256
1/16
3/32
1/8
5/32
3/161/49/325/16
3/8
1/2
9/165/8
3/47/81"
1-1/81-1/4
1-1/2
1-3/4
2"
8007086375795104253643182832552121821591421271161069891807164585347433935333028272423
1194106595586976463754647842538231927323921219117415914713611910696878071645853494642403734
1592141512741158101984972863756651042536431928325523221219618215914112711610694857771656157534946
17911598143313031147955819718637573477409358318286260238220205179159143130119106958780736864605551
1988176815911446127410619097967076375304553983543182892652452771991771591451331181069688827671666157
2386212119091736152712731091955849764636546477425382347318294273239212191174159141127116106989185807368
Revolutions
TAP PERIPHERAL SPEED
69
15 18 21 25 27 30 36
298326522386216919091591136411931061955795682597531477434398367341298265239217199177159145133122114106999285
3579318228632603229119091636143212731146954818716637573521477441409358318286260239212191174159147186127119110102
41763712334130372673222719091671148513371113955835742668608557514477418371334304275245223203186171159149139129119
497144193977361631822651227319891768159113261136994885795723663612568497442398362331295265241221204189177166153142
5369477342953905343628642455214819091719143212271074955859781716661614537477430391353318286360239220205191179165153
59655303477343393818318227272387212219091592136411931061955868796734682597530477434398354318289265245227212199184170
7158636457275207458238183273286425462292190916361432129311461041955881818716636573521477424382347318294273255239220205
per Minute
TO rpm CONVERSION CHART
70
CORRECT USE OF TAPS
A guide to successful machine tapping
• Use the correct tap to suit the application (see page 51/54).• Select the correct tapping drill size (see page 55/61).• Direct an adequate supply of the recommended lubricant to
the cutting area of the tap (see page 63/65).• Make sure the workpiece is securely held.• Use a tapping attachment suited to the application and align
the tap with the hole.• When using a machine without lead screw feed, hand feed
the tap until sufficient engagement produces self feed.• When using a machine with lead screw feed, set the lead to
correspond with that of the tap. This also applies on two andmulti start taps.
Preparation of HolesA good hole is a pre-requisite of a good thread. Some of the factorswhich contribute to inferior threads are:
(a) Out of round holes. The thread will be correspondingly out ofround.
(b) Poor surface finish in the hole.(c) Size of the hole. A hole which is too small will cause overloading
of the tap with the possible breakage.(d) Hard spots and abrasive surfaces in the cored holes. These
holes should be pre-drilled.
Percentage Thread DepthFor general purpose work a thread depth of 75% is recommended.A drill size equal to the minor diameter of the tap produces a 100%thread depth. This practice is normally recommended fot the followingreasons.(a) 100% thread depth requires excessive power to turn the tap,
with consequent possible breakage.(b) 100% thread depth is only 5% stronger than the normal depth
of 75%.(c) Even a 50% thread depth still produces a thread stronger than
its mating bolt.
71
ROOTRAD.
THREADANGLE 1/2
PITCH
WIDTH OFFLAT CREST
CRESTRAD.
MIN
OR
DIA
.
EF
FE
CT
IVE
DIA
.
MA
JOR
DIA
.TR
IAN
GU
LAR
HE
IGH
T
NUT
BOLT
CRESTRAD.
BASIC DEPTHOF THREAD
WIDTH OFFLAT ROOT
ROOTRAD.
MIN
OR
DIA
.
EF
FE
CT
IVE
DIA
.
MA
JOR
DIA
.
1/2PITCHPITCH
Basic sizes and tolerance classes
To allow for clearance between mating internal and external threads,taps are manufactured with oversize allowances added to the basicdiameters.These basic diameters plus the oversize allowances establish:
(a) the minimum effective diameter; and
(b) the minimum major diameter.
72
Limits of Tolerance
Effective Diameter - The tolerance is the amount of variationallowed in the manufacture of the tap. This tolerance is added to theminimum effective diameter to establish the maximum effectivediameter.
It follows that:Basic Effective + Oversize
= Minimum Effective
Basic Effective + Oversize + tolerance= Maximum Effective
The effective diameter can only be measured with special tapmeasuring equipment.
Major Diameter - The minimum major diameter is established byadding the oversize allowance to the basic major diameter (thenominal thread size). Therefore, on measurement, the major diameterof the tap is larger than the nominal thread size, and must not beused to judge the size of the tap.
The maximum major diameter of the tap is governed by the threadform and is therefore not subject to a tolerance.
73
Tap Tolerance Classes
Relationships of Tap Classes to Nut Tolerances
Metric Threads
Unified Threads
6G(MAX)5G(MAX)
4G(MAX)
MINIMUM'G' GRADES
NUTS8H(MAX)
7H(MAX)6H(MAX)
5H(MAX)4H(MAX)
MIN.'H' GRADES
BASICPITCH DIAMETER
12345123451234512345
TO
LER
AN
CE
BA
ND
12345123451234512345
12345123451234512345
CLA
SS
1
CLA
SS
2
CLA
SS
3
TO
LER
AN
CE
BA
ND
NUTS1B(MAX)
2B(MAX)
3B(MAX)
MINIMUM ALL NUT CLASSES BASICPITCH DIAMETER
12341234123412341234
12345123451234512345123451234512345
12345123451234512345123451234512345
CLA
SS
1
CLA
SS
2 CLA
SS
3
74
Class 1 TapThis is closest to basic, having little oversize allowance, and isnormally specified for "close" fit threads, eg. Unified 3B, Metric 4H,5H.
Class 2 TapThis is normally specified for "medium" fit threads, eg. Unified 2B,Metric 6H, 4G, 5G.
Class 3 TapThis is futhermost above basic size and used for "free" fit threads,eg. Unified 1B, Metric 7H, 8H, 6G.Under favourable working conditions, the following thread tolerancesshould be produced by the new class taps.
All Somta HSS taps are supplied to Class 2, 6H unless otherwisespecified.
RE-SHARPENINGMaximum productivity and tap life can only be obtained from a tapthat is kept in good condition and handled with care.
When re-sharpening becomes necessary, regrinding by hand is notrecommended, though it is probably better than using chipped orworn taps. The recommended method is to use special tap grindingattachments or machines, and to follow the original form of the tap.
MetricUnifiedWhitworth FormBA
Class 14H, 5H3BClose ClassClose Class
Class 26H, 4G, 5G2BMedium ClassMedium Class
Class 37H, 8H, 6G1BFree ClassFree Class
75
TAPPING PROBLEMS: CAUSES AND SOLUTIONS
Damaged tap threads in the hole
(a) Possible CauseMis-alignment of the tap with the hole before starting to tap.SolutionCare must be taken to align the tap with the hole before startingto tap.
(b) Possible CauseThe tap is too dullSolutionUse a tap which is in good condition.
(c) Possible CauseWork hardened skin in the drilled hole.SolutionWork hardening can be avoided when drilling by using the correctspeeds,and coolants. See page 63/65. Use serial taps.
(d) Possible CauseIncorrect rake angleSolutionUse the recommended tap for the material. See page 51/54.
Poor finish of the thread(a) Possible Cause
Using the incorrect tap.SolutionUse the recommended tap.
(b) Possible CauseThe drilled hole is too small.SolutionUse the recommended drill size. See page 55/61.
(c) Possible CauseThe tap is too dull.SolutionUse a tap which is good condition.
(d) Possible CauseInsufficient number of threads on the lead.SolutionUse a tap with the correct lead.
76
(e) Possible CauseMis-alignment of the tap and the hole.SolutionCare must be taken to align the tap with the hole before startingto tap.
(f) Possible CauseIncorrect rake angleSolutionUse the recommended tap for the material. See page 51/54.
Torn threads in the tapped hole(a) Possible Cause
The flutes are clogged by chips.SolutionUse a spiral point or a spiral flute tap.
(b) Possible CauseDistortion of the walls in a thin walled workpiece.SolutionUse a multi-fluted tap.
(c) Possible CauseThe threads on the tap are broken.SolutionUse a tap which is in good condition.
(d) Possible CauseLack of/or the wrong type of lubricant.SolutionApply an adequate supply and the correct type of lubricant tothe cutting area. See page 63/65.
(e) Possible CauseUsing the incorrect or unsuitable tap for the material.SolutionUse the recommended tap for the material. See page 51/54.
(f) Possible CauseTap hitting the bottom of the hole.SolutionAllow sufficient clearance at the bottom of the hole.
(g) Possible CauseIncorrect rake angle.SolutionUse the recommended tap for the material. See page 51/54.
77
Excessive Tap Wear(a) Possible Cause
Mis-alignment of the tap and the hole.SolutionCare must be taken to align the tap with the hole before startingto tap.
(b) Possible CauseLack of /or the wrong type of lubricant.SolutionApply an adequate supply and the correct type of lubricant tothe cutting area.
(c) Possible CauseThe material is abrasive.Solution(i) Use the correct type of tap.(ii) Use a surface treated tap.
(d) Using the incorrect tap.Solution(i) Use a tap with the correct lead.(ii) Use a surface treated tap.
(e) Possible CauseIncorrect rake angleSolutionUse the recommended tap for the material. See page 51/54.
Over-Heating of tap(a) Possible Cause
Lack of / or the wrong type of lubricant.SolutionApply an adequate supply and the correct type of lubricant tothe cutting area.
(b) Possible CauseThe tap is too dull.SolutionUse a tap which is in a good condition.
(c) Possible CauseThe wrong type of tap is used.SolutionUse the recommended tap. See page 51/54.
78
(d) Possible CauseExcessive tapping speed is applied.SolutionUse the recommended tapping speed. See page 63/65.
Bell-Mouthed Tapped Hole(a) Possible Cause
Mis-alignment of the tap and the hole.SolutionCare must be taken to align the tap with the hole before startingto tap.
(b) Possible CauseThe workpiece is not rigidly held.SolutionSecure the workpiece
(c) Possible CauseExcessive pressure is applied when starting to tap.SolutionOnly sufficient pressure to initiate self-feeding should be applied.
(d) Possible CauseInsufficient number of threads on the lead.SolutionUse a tap with a longer lead.
(e) Possible CauseThe drilled hole is too small.SolutionUse the recommended drill size. See page 55/61.
Over-size tapped hole(a) Possible Cause
Using the incorrect tap.SolutionUse the recommended tap. See page 51/54.
(b) Mis-alignment of the tap and the hole.SolutionCare must be taken to align the tap with the hole before startingto tap.
(c) Possible CauseLack of / or wrong type of lubricant.Solution
79
Apply an adequate supply and the correct type of lubricant to the cutting area.(d) Possible Cause
Incorrect rake angle.SolutionUse the recommended tap for the material. See page 51/54.
Tap binding in the hole(a) Possible Cause
Using the incorrect tap.SolutionUse the recommended tap.See page 51/54.
(b) Possible CauseThe drilled hole is too small.SolutionUse the recommended drill size. See page 55/61.
(c) Possible CauseLack of / or the wrong type of lubricant.SolutionApply an adequate supply and the correct type of lubricant tothe cutting area. See page 63/65.
(d) Possible CauseThe flutes are clogged with chips.SolutionUse a spiral point or a spiral flute tap.
(e) Possible CauseIncorrect rake angle.SolutionUse the recommended tap for the material. See page 51/54.
Flutes clogged with chips(a) Possible Cause
Using the incorrect tap.SolutionUse a spiral point or spiral flute tap.
(b) Possible CauseLack of / or the wrong type of lubricant.SolutionApply an adequate supply and the correct type of lubricant tothe cutting area.
80
Tap Breakage(a) Possible Cause
Using the incorrect tap.SolutionUse the recommended tap. See page 51/54.
(b) Possible CauseThe tap is too dullSolutionUse a tap which is in good condition.
(c) Possible CauseThe drilled hole is too small.SolutionUse the recommended tapping drill size. See page 55/61.
(d) Possible CauseThe drilled hole is too shallow.SolutionAllow clearance at the bottom of the hole when drilling.
(e) Possible CauseMis-alignment of the tap and the hole.SolutionCare must be taken to align the tap with the hole before startingto tap.
(f) Possible CauseThe flutes are clogged with chips.SolutionUse a spiral point or spiral flute tap.
(g) Possible CauseExcessive tapping speed is applied.SolutionUse the recommended tapping speed. See page 63-65.
(h) Possible CauseThe tap holding device is not suitable.SolutionUse the appropriate tapping attachment.
(i) Possible CauseThe work material is work hardened.SolutionUse serial taps.
(j) Possible CauseLack of / or the wrong type of lubricant.
81
Lack of / or the wrong type of lubricant.SolutionApply an adequate supply and the correct type of lubricant tothe chamfer lead of the tap.
(k) Possible CauseIncorrect rake angle.SolutionUse the recommended tap for the material. See page 51/54.
82
END MILLS
END MILL NOMENCLATURE
Shank Options
Plain ShankTolerance h7 on metricshank diameter (see page121 for tolerance tables)
Threaded Shank
Tolerance h8 on metric /Fractional shank diameter
Flatted Shank
Tolerance h6 on metricshank diameter (see page121 for tolerance tables
OVERALL LENGTH
CUTTING LENGTH
THREADLENGTH
CUTTINGDIAMETER
SHANKDIAMETER
ENDTEETH
HELIXANGLE
THREAD20 T.P.I.WHITWORTHFORM
83
Two Flute End Mill
Tolerance e8 on cuttingdiameter (see page 121 for tolerance tables)
Ball Nose End Mill
Tolerance e8 on cuttingdiameter (see page 121 fortolerance tables)
Three Flute End Mill
Tolerance e8 on cuttingdiameter (see page 121 fortolerance tables)
Multi-Flute End Mill
Tolerance k10 on cuttingdiameter (see page 121 fortolerance tables)
Roughing End Mill
Tolerance k10 on cuttingdiameter (see page 121 fortolerance tables)
Typical End Mill Options
84
END MILL APPLICATIONS
Two and Three Flute End Mills
Two and three flute end mills are shank type cutters withperipheral teeth and end teeth of the plunging type. Intended forgeneral purpose use, they have right hand cutting, right handhelical teeth; they are used on keyway and closed slottingoperations where the close minus tolerance of the cuttingdiameter allows slot widths to be produced in one pass. Thesecutters are also extensively used when profiling and end millingaluminium alloys, due to the greater chip space required by thismaterial.
Ball Nose Two Flute End Mills
Ball nosed two flute end mills are manufactured to the sametolerances as the normal two flute end mill, and have a centrecutting ball end. They are used extensively in die making forcutting fillets, radiused slots, pocketing etc. These cutters haveright hand cutting, right hand helical teeth.
85
Multi-Flute End Mills
Multi-flute end mills are shank type cutters with peripheral teethand end teeth of the both plunging and non-plunging type.Designed for general purpose use they have right hand cutting,right hand helical teeth, and are used in stepping and profilingapplications. They can also be used on slots where the plustolerance of the cutting diameter is not critical.
Roughing End Mills
Shank type cutters with right hand cutting, right hand helicalteeth on the periphery with roughing profile and with heavy dutyend teeth. These cutters are robust and durable even underheavy cutting conditions on a wide range of materials. They areintended for rapid and heavy rates of stock removal wheresurface finish is of lesser importance. Available in coarse andfine pitch knuckle form and flat crest type.
86
HINTS FOR SUCCESSFUL END MILL USAGEIt is assumed that the workpiece clamping and machine size andpower are adequate for the intended operation.
Always select the most suitable tool for the job on hand; a fewminutes spent on selection can save hours of machining. Useroughing end mills when removing large amounts of stock; twoor three flute end mills for deep slotting applications, for edgecutting and espically when machining light alloys. Use multi-fluteend mills for edge cutting as well as for light finishing cuts.
Use threaded shank or flatted shank cutters where heavy stockremoval and high tooth loads are involved. Plain shank cuttersare particularly suitable for quick change CNC applications andfor pre-setting off the machine.
Where possible check workpiece condition and hardness.
Check chucks and collects regularly ensuring that they are ingood condition. Always clean cutter shanks and collets prior toassembly. Check that cutters are running true.
The most likely cause of cutter run-out is damaged chucks andcollets.
Maintain cutters in a sharp condition to ensure maximum stockremoval, surface finish and maximum power requirement.
Re-sharpen immediately when signs of wear are visible, sinceregrinding is then a relatively quick operation requiring little stockremoval and with resulting increase in tool life. (See page 123for resharpening details). Cutter storage is of paramountimportance due to the brittle nature of the hardened cutting edgesof all cutting tools. Poor storage often causes damage such aschipping of the cutting edges and breakage of corners, resultingin a tool which is useless. As in all machining operations cleanilessis essential.
The best machining results are produced by cutters operating atthe correct speed and feed to suit the material being worked.(See page 104/107 for technical data.)
87
SHANK CUTTERS
SHANK CUTTER NOMENCLATURE
SHANKDIAMETER
THREAD 20 T.P.I.WHITWORTHRIGHT HAND
RECESSDIAMETER
SIDETEETH
HELIXANGLE
CUTTER DIAMETER
CU
TT
ING
WID
TH
RE
CE
SS
LE
NG
TH
SH
AN
K L
EN
GT
H
OV
ER
ALL
LE
NG
TH
TH
RE
AD
LEN
GT
H
88
Types of shank cutters
Dovetail Cutter
Tolerance js16 on cutting diameter(see page 121 for tolerance tables)
Inverted Dovetail Cutter
Tolerance js16 on cutting diameter(see page 121 for tolerance tables)
Corner Rounding Cutter
Tolerance H11 on radius and js14 on cutting tip(see page 121 for tolerance tables)
89
T-Slot Cutter
Tolerance d11 on metric cutting diameter and widthTolerance h12 on fractional cutting diameter and width(see page 121 for tolerance tables)
Woodruff Cutter
Tolerance h11 on metric cutting diameter and e8 on width(see page 121 for tolerance tables)
Tolerance on fractional diameter issize +0,381
+0,127and on width issize +0,000
- 0,025
90
SHANK CUTTER APPLICATIONS
Dovetail Cutters
These angle cutters have right hand cutting straight teeth andnon-plunging end teeth. They are used wherever dovetails orangles are required and are available in a range of angles anddiameters.
Corner Rounding Cutters
Straight tooth cutters with right hand cutting teeth. Intended toproduce a true convex up to 90° of arc.
91
T-Slot Cutters
Shank type cutters with right hand cutting alternate helicalperipheral teeth as well as teeth on either face. Intended foropening out existing slots to form the T-slots used extensively onmachine tables. They are produced in a range of diameters andwidths to allow clearance on a standard range of bolt headsizes.
Woodruff Cutters
Shank type cutters with right hand cutting alternate helicalperipheral teeth. Available in a range of diameters and widths.Designed to produce slots to suit standard woodruff keys.
HINTS FOR SHANK CUTTER USAGE
(See page 86 for hints on end mill usage)
92
LAND
RAKEANGLE WIDTH
KEYWAY
PERIPHERALCLEARANCE
PERIPHERALTEETH
SIDE TEETH
HELIXANGLE
DIAMETER
SIDE TEETHCONCAVITY
BORE
ARBOR MOUNTED CUTTERS
SIDE AND FACE CUTTERNOMENCLATURE
Side and Face Cutter- (Staggered Tooth shown)
Tolerance js16 on metric cutting diameter and k11 on width(see page 121 for tolerance tables)
93
OVERALLLENGTH
RAKEANGLE
HELIXANGLE
INTERNALDIAMETER
DIA
ME
TE
RShell End Mills
Plain Form
See page 98 for application.
Roughing Form
See page 98 for application.
94
Side and Face Cutter- Straight Tooth
Tolerance js16 on metric/fractional cutting diameter and k11 onmetric/fractional width(see page 121 for tolerance tables)
Cylindrical Cutter
Tolerance js16 on cutting diameter and width(see page 121 for tolerance tables)
95
Single Angle Cutter
Tolerance js16 on cutting diameter and js14 on width(see page 121 for tolerance tables)
Double Angle Cutter
Tolerance js16 on cutting diameter and width(see page 121 for tolerance tables)
96
ARBOR MOUNTED CUTTER APPLICATIONS
Staggered Tooth Side and Face Cutters
As the name suggests, side and face cutters have teeth on theperiphery as well as on the sides, Designed with rugged alternatehelical teeth, these cutters offer optimum performance whenused for deep slotting with rapid stock removal; the cutting actionof the alternate helical teeth combined with the coarse pitchedside teeth giving excellent qualities of smooth cutting, efficientstock removal and good surface finish.
Straight Tooth Side and Face Cutters
Intended for light cuts and shallow slotting operations, the straighttooth side and face cutter is often used in a straddle millingfunction where two parallel surfaces are machinedsimultaneously. It is considered to be a compromise tool due tothe reduced cutting action of its straight teeth, which causegreater shock when meeting the workpiece than cutters withhelical teeth.
97
Cylindrical Cutters
Intended for medium/light surfacing cuts these helical cuttersoffer the benefits of shock reduction combined with a goodcutting action.
Angle Cutters
Produced with light duty straight teeth these cutters are usedmainly for cutting dovetails, serrations and angled slots on lessdifficult materials.
98
Shell End Mills
With helical peripheral teeth these cutters fillthe gap betweennormal shank cutters and the much larger facing cutters,thiscuttter is better suited to light/medium cuts in a facing or steppingoperation with its plain bore.
Shell End Mill (Roughing)
As the name implies, these cutters with their helical teeth androughing profile are particularly efficient in areas where largevolumes of stock must be removed at high speed and wheretough materials are to be worked.
99
SLITTING SAWS
Slitting Saw - Plain
Tolerance js16 on cutting diameter and js10 on width(see page 121 for tolerance tables)
Slitting Saw - Side Chip Clearance
Tolernace js16 on cutting diameter and js10 on width(see page 121 for tolerance tables)
100
SLITTING SAW APPLICATIONS
Slitting Saw - Plain
Intended for shallow cutting-off operations, these saws havestraight teeth on the periphery and are tapered on width towardsthe bore to prevent binding. They are available in either coarseor fine pitch to suit the type and section of materials to be cut.
Slitting Saws - Side Chip Clearance
Intended for optimum production of deep narrow slots and forsawing operations, these saws have alternate helical teeth onthe periphery combined with side teeth to ensure efficient stockremoval, clean cutting action, and good surface finish.
101
± 2 times depth of cut
HINTS FOR SUCCESSFUL SLITTING SAW USAGE
It is recommended that side plates be used with slitting saws.
102
HINTS FOR SUCCESSFUL ARBOR MOUNTED CUTTER USAGE
Some of the many factors governing efficient use of bore cuttersare:-
1) Condition of machine2) Machine power available3) Machine capacity4) Nature of the workpiece
Attention should be given to these factors prior to commencement.When using arbor mounted cutters the following points shouldbe observed:-
Taper drive of arbor should be in good condition and fit correctlyinto machine drive.
Arbor and bushes should be kept in good and clean condition;dirty bushes cause run-out of cutters.
Arbors should be oiled and carefully stored when not in use;bent arbors are useless and expensive to replace.
Cutters should run true to prevent overloading of one or twoteeth and extensive regrinding later.
Fit the cutter as closely as possible to the machine column witha support as near to the cutter as the workpiece will allow.
Running bushes and support bearings should be kept clean andin good running condition, particularly with regard to the bushfaces. Lack of support will cause damage to the cutter and theworkpiece. Always use correct lubricants.
Workpiece clamping should be rigid and able to withstand theforces acting upon it under the action of the cutter.
Select correct speeds and feeds for the cutter in use and thenature of the workpiece material and the size of the cut to betaken.
103
Use recommended coolants and direct flow to the point of cutting.Consult the coolant suppliers for specific recommendations.Adequate cooling is essential to prevent overheating of the cutterand failures associated with overheating.
Always use drive keys between the cutter and the arbor; frictionbetween the cutter and the arbor bushes is seldom sufficientwhen cutters are under correct load.
Never force a cutter onto a arbor or over an ill-fitted key. Protectyour hands by wrapping the cutter in a soft material when fittingor removing it from the arbor.
Due to the brittle nature of hardened tool steels it is not advisableto “remove” a cutter with a mallet once it has been tightened ontothe arbor.
Maintain cutters in sharp condition. Regrind as soon as wearbecomes apparent.
Store cutters carefully when not in use, using a light film of oil toprevent rusting.
Cleanliness of cutters and arbors is essential.
Use helically fluted cutters wherever possible to minimise shockas teeth contact the workpiece.
104
TECHNICAL INFORMATION
CUTTER TECHNICAL DATA
MATERIALTYPE
GRADE
CARBONSTEEL
FREE CUTTING
0.3 to 0.4% Carbon
0.3 to 0.4% Carbon
0.4 to 0.7% Carbon
0.4 to 0.7% Carbon
HARDNESSHB
TENSILESTRENGTH
N / mm²
ALLOYSTEEL
150
170
248
206
286
510
580
830
675
970
248
330
381
833
1137
1265
STAINLESSSTEEL
Martensitic: Free CuttingStd. Grade
Austenitic: Free CuttingStd. Grade
As Supplied
248248
833833
TITANIUM
Titanium Comm: Pure
Titanium Comm: Pure
Titanium Comm: Pure
Titanium Alloyed
Titanium Alloyed
Titanium Alloyed
NIMONICALLOYS
Wrought
Cast
300
350
1030
1200
170
200
275
340
350
380
510
660
940
1170
1200
1265
TOOL STEEL
HSS Standard Grades
HSS Cobalt Grades
Hot Working Steel
Cold Working Steel
225
250
250
250
735
830
830
830
CASTIRONS
Grey, Malleable
Hardened
240
330
800
1137
105
PERIPHERAL SPEED RANGERefer to explanatory notes on page 32, 33
PRIMARYCLEARANCE
† CUTTING ANGLES
8° - 20°
16-20
12-18
9-15
4-8
TYPE*A
TYPE*B
TYPE*C
TYPE*D
SECONDARYCLEARANCE
RADIALRAKE
30-40
24-32
18-25
24-32
16-25
28-40
24-32
18-25
24-32
16-20
24-32
20-26
14-20
20-26
12-20
30-40
24-32
18-25
24-32
16-25
Add 10°to
primary9° - 14°
16-20
12-18
8-14
12-16
10-15
8-12
16-20
10-16
8-12
8° - 20°Add 10°
toprimary
9° - 14°
10-205-10
10-205-10
12-165-10
12-165-10
8-154-8
8-154-8
10-205-10
10-205-10
8° - 20°Add 10°
toprimary
5-10 3-7 4-8 8° - 20° Add 10° toprimary
9° - 14°
9° - 14°
7-12 5-12 5-10 7-12 8° - 20°
Add 10°
to
primary
9° - 14°
10-20
10-16
10-16
10-16
10-20
10-20
10-16
10-16
8-15
8-13
8-13
8-13
10-20
10-16
10-16
10-16
8° - 20°Add 10°
toprimary
9° - 14°
16-20
12-16
16-20
10-14
12-16
10-12
20-28
16-228° - 20°
Add 10° to
primary9° - 14°
cont on page 106
106
CUTTER TECHNICAL DATA (cont)
MATERIALTYPE
GRADE
ALUMINIUMALLOYS
Wrought
Wrought
Cast
HARDNESSHB
TENSILESTRENGTH
N / mm²
COPPERALLOYS
55
110
100
PLASTICS
Brass : Free Cutting Low LeadedBronze: Silicon Manganese Aluminium PhosporCopper
As Supplied
As Supplied
TYPE CUTTER RANGE
A
End mills (2, 3 & Multi-Flute)T - Slot CuttersDovetail & Inverted Dovetail CuttersWoodruff CuttersCorner Rounding Cutters
B
C
Side and Face CuttersSingle and Double Angle CuttersSlitting Saws
Shell End Mills - Plain Tooth
Explanatory Notes
*Cutter types
107
PERIPHERAL SPEED RANGERefer to explanatory notes on page 32, 33
PRIMARYCLEARANCE
† CUTTING ANGLES
10° - 20°
40-7050-8040-7025-4515-2515-2540-70
TYPE*A
TYPE*B
TYPE*C
TYPE*D
SECONDARYCLEARANCE
RADIALRAKE
200-1500
100-250
40-100
120-180
100-180
50-70
50-180
50-100
30-80
Add 10°
to
primary
20° - 28°
8° - 20°Add 10°
toprimary
9° - 14°
50-200 50-200 10° - 20°Add 10°
toprimary
9° - 14°
35-4545-7035-4520-4015-2515-2535-45
30-6040-6530-6020-3512-2012-2030-60
8° - 20°Add 10° to
primary 9° - 14°
10° - 20° Add 10° 20° - 28°
TYPE CUTTER RANGE
D Shell End Mills - Roughing
Note: For Roughing End Millssee page 85.
Use higher angles for smaller diameters, reducing proportionatelyfor larger diameters.
*Cutter types (cont)
† Cutting Angles
108
END MILLS: Feeds Per Tooth Sz (mm)
345681012141618202225283032354050
EndMill
Table Shows Sz Values
CarbonSteels
AlloySteels
StainlessSteels
NimonicAlloys
Titanium
0.0100.0150.0180.0220.0300.0360.0440.0510.0580.0650.0730.0800.0900.1020.1100.1160.1300.1300.130
0.0100.0150.0180.0220.0300.0360.0440.0510.0580.0650.0730.0800.0900.1020.1100.1160.1300.1300.130
0.0100.0150.0180.0220.0300.0360.0440.0510.0580.0650.0730.0800.0900.1020.1100.1160.1300.1300.130
0.0080.0120.0140.0180.0240.0290.0360.0400.0460.0520.0580.0640.0720.0810.0880.0920.1040.1040.104
0.0100.0150.0180.0220.0300.0360.0440.0510.0580.0650.0730.0800.0900.1020.1100.1160.1300.1300.130
Sz X 1.25 Sz X 0.78
ar = 0.1 X d ar = 0.25 X d
aa =
d
aa =
d
a aaa
109
Table Shows Sz Values
ToolSteels
CastIrons
ManganeseSteels
AluminiumAlloys
CopperAlloys
0.0090.0130.0160.0200.0270.0320.0400.0460.0520.0580.0650.0720.0800.0910.1000.1040.1170.1170.117
0.0100.0160.0220.0280.0360.0400.0450.0560.0640.0700.0800.0880.0950.1100.1200.1270.1420.1420.142
0.0080.0120.0140.0180.0240.0290.0360.0400.0460.0520.0580.0640.0720.0810.0880.0920.1040.1040.104
0.0130.0190.0230.0280.0390.0460.0570.0660.0750.0850.0920.1041.1170.1320.1430.1500.1700.1700.170
0.0130.0190.0230.0280.0390.0460.0570.0660.0750.0850.0920.1040.1170.1320.1430.1500.1700.1700.170
Sz Sz
ar = d
aa =
0.5
X d
aa =
0.5
X d
a aaa
ar = d
110
ROUGHING END MILLS:Peripheral Speed (m/min)Feed Per Tooth Sz (mm)
68
1012141622252830323538404550
EndMill
Size
Table Shows Sz Values
1 2 3 4
0.0080.0130.0170.0230.0260.0300.0320.0350.0350.0400.0420.0130.0450.0450.0470.060
0.0080.0130.0200.0250.0300.0380.0400.0420.0450.0450.0500.0130.0570.0570.0590.074
0.0090.0150.0200.0250.0300.0380.0400.0420.0420.0450.0500.0150.0570.0570.0600.075
0.0100.0150.0210.0330.0370.0440.0480.0500.0500.0560.0640.0150.0700.0700.0750.090
Material Group
Sz Sz X 1.5 Sz X 1.8
d 0.3 d 0.5 d
d 1.5
d
1.5
d
111
Table Shows Sz Values
5 6 7 8
0.0130.0200.0300.0370.0470.0530.0600.0630.0650.0680.0800.0200.0860.0900.0940.119
0.0080.0120.0170.0240.0260.0330.0380.0400.0400.0400.0440.0120.0480.0480.0480.060
0.0060.0090.0130.0160.0210.0240.0250.0280.0280.0300.0360.0090.0400.0400.0420.052
0.0060.0090.0120.0130.0150.0190.0220.0250.0250.0280.0350.0090.0350.0380.0400.047
Material Group
Peripheral Speeds
MaterialGroup
Cutter Speed(m/min)
Material Types
1
2
3
4
5678
Steels up to 500N/mm²Malleble Cast Iron up to 120 HB
Steels of 500 - 800 N/mm²Non - Alloyed Tool SteelsPure Titanium
Steels of 800 - 1200 N/mm²Hot Working SteelsCast Iron of 120 - 180 HB
Stainless SteelsTitanium Alloys (Annealed)Cast Iron of more than 180 HB
Titanium Alloys (Hardened)Brass and Bronze (Cast)Brass and Bronze (Rolled)Plastics and similar
28 - 40
24 - 32
18 - 25
12- 18
7 - 1235 - 4545 - 70
200 - 250
112
SIDE AND FACE CUTTERS - Staggered Tooth:Feed Per Tooth (mm)
63
80
100
125
160
200
250
CutterDiameter
Table Shows Sz Values
CutterWidth 1 2 3
over3
104
125
147
167
188
188
18
0.0500.0520.0630.0640.0690.0700.0770.0780.0880.0900.0930.1010.1070.105
0.0510.0540.0630.0640.0690.0690.0780.0780.0900.0900.0930.1010.1070.105
0.0510.0540.0700.0700.0700.0700.0800.0800.1000.1900.1940.1020.1100.106
Material Group
to1018122014251628183218321832
b
0.1
d
113
0.0500.0520.0630.0630.0700.0700.0780.0780.0900.0900.0930.1020.1080.104
Table Shows Sz Values
6 7 8
0.0510.0530.0630.0630.0700.0700.0800.0800.0900.0900.0940.1020.1100.105
0.0500.0520.0630.0630.0700.0700.0800.0800.0900.0900.0930.1010.1080.104
0.0460.0480.0560.0560.0620.0700.0800.0800.0900.0900.0930.1010.1080.104
0.0200.0200.0200.0200.0200.0200.0200.0200.0200.0200.0200.0200.0200.020
Material Group
4 5
b
0.1
d
114
SHELL END MILLS:Feed Per Tooth (mm)
Plain Tooth
PLAIN
Type
Table Shows Sz Values
CutterDiameter 1 2 3
0.0800.0800.1000.1000.1000.1000.105
Material Group
40506380100125160
ROUGHING
0.0800.0800.1000.1000.1000.1000.105
0.0800.0800.1000.1000.1000.1000.105
40506380100125160
0.0600.0700.0750.1000.1100.1150.120
0.0600.0700.0800.1000.1100.1150.120
0.0600.0700.0700.1000.1100.1150.125
0.75 d0.
1 d
115
Table Shows Sz Values
6 7 8
0.0800.0800.1000.1000.1000.1000.105
Material Group
0.0800.0800.1000.1000.1000.1000.105
0.0220.0220.0220.0220.0220.0220.022
0.0600.0750.0800.1000.1100.1150.120
4 5
0.0800.0800.1000.1000.1000.1000.105
0.0800.0800.1000.1000.1000.1000.105
0.0600.0750.0800.1000.1100.1150.120
0.0600.0750.0800.1000.1100.1150.120
0.0600.0750.0800.1000.1100.1150.120
0.0220.0280.0310.0390.0390.0420.044
0.75 d
0.15
d -
0.25
d
Roughing Form
116
v =
Sz =
rpm =
Sn =
S¹ =
V =
p =
v = speed (m/min)
D = cutter diameter (mm)
rpm = revolutions/min
Sn = feed/revolution (mm)
S¹ = feed/minute (mm)
Sz = feed/tooth (mm)
Z = number of teeth on cutter
V = chip volume (cm³/min)
a = depth of cut (mm)
b = length of cut (mm)
D. p. rpm1000
S¹rpm.Z
V. 1000p.D
S¹rpm
Sz. Z. rpm
a. b. S¹1000
3.1416
Speed and Feed Formulae
117
CLIMB OR CONVENTIONAL MILLING
From the very beginning of the milling process, it was foundpractical to always rotate the end mill in the opposite direction tothe feed of the workpiece. This is termed conventional milling.
In conventional milling the end mill engages the workpiece at thebottom of the cut. The end mill teeth slide along until sufficientpressure builds up to break through the surface of the work.This sliding action under pressure tends to abrade the peripheryof the end mill with resulting dulling. Also in horizontal conven-tional milling, the cutting action has a tendency to lift the workpiece,fixture and table from their bearings. In recent years, millingmachines have been greatly improved through backlash elimina-tion and greater rigidity so that climb milling is now possible.Climb milling improves surface finish and increases tool life.
Conventional Milling
Climb Milling
Feed
Feed
Force
Force
118
In climb milling the end mill rotates in the direction of the feed. Thetooth meets the work at the top of the cut at the thickest portionof the chip. This provides instant engagement of the end mill withthe workpiece producing a chip of definite thickness at the startof the cut without the rubbing action resulting from conventionalmilling. It further permits the gradual disengagement of the teethand work so that feed marks are largely eliminated.
Climb milling will often provide better product finish, permit greaterfeed per tooth and prolong the cutter life per sharpening. It isparticularly desirable to climb mill such materials as heat treatedalloy steels and non-free machining grades of stainless steel forbetter tool life and to reduce work hardening. It is not recom-mended on material having a hard scale, such as cast or scalyforged surfaces, because abrasion would quickly ruin the cut-ting edges. Also some very soft steels do not lend themselves toclimb milling because of their tendency to drag and tear.
Climb milling cannot be applied to every milling operation andshould not be attempted if the material and the machine setup arenot adapted to this type of milling.
119
PROBLEM SOLVING
Milling problems are often caused by one or more of the follow-ing factors, which should be carefully checked in a systematicand logical manner.
Speeds and FeedsSee page 104/107 for recommendations.
CoolantsSeek advice from your supplier.
Cutter SelectionAlways select the correct type and quality of cutter to suit theapplication.
ArborsStraightness/runout/size/wear/damageBushing-wear/damage.
Re-sharpeningClearance angles. See page 123.RunoutBurning/overheatingSurface finish
Milling MachinesSlides and gib stripsLead screws and nutsBacklash eliminationAttachmentsDefective workheadsWorn tailstocksWorn centres
120
WorkholdingWorkdolder conditionWorkholder suitabilityWorkholder alignmentWorkholder rigidity
Workpiece ConditionMachine suitabilityMaterial specificationsMaterial hardnessMaterial surface conditionsMachining characteristics
Cutter HoldersColletsChucksDraw barsRunoutDamage
121
+75 0
+900
+110 0
+1300
+1600
+1900
+2200
+60 0
H11
+70-70
+60-60
+50-50
+42-42
+35-35
+24-24
3 to6mm
6 to 10mm
10 to18mm
18 to30mm
30 to50mm
50 to80mm
80 to120mm
-30-105
-40-130
-50-160
-65-195
-80-240
-100-290
-120-340
-20-38
-25-47
-32-59
-40-73
-50-89
-60-106
-72-126
0-75
0-90
0-110
0-130
0-160
0-190
0-220
0-120
0-150
0-180
0-210
0-250
0-300
0-350
+150 -150
+180 -180
+215 -215
+260 -260
+310 -310
+370 -370
+435 -435
+375 -375
+450 -450
+550 -550
+650 -650
+800 -800
+950 -950
+1100 -1100
3mm
-20-80
-14-28
d11
0-60
0-100
+300 -300
+125 -125
Tolerances in µm = 1 micron (1/1000mm)
DIAMETER OR WIDTH
0-6
0-14
0-8
0-9
0-11
0-13
0-16
0-19
0-22
0-18
0-22
0-27
0-33
0-39
0-46
0-54
+90-0
+110-0
+130-0
+160-0
+190-0
+220-0
+60-0
+75-0
+29-29
+20-20
e8
h11
h12
js16
h6
h8
k11
js10
js14
Tol.
TOLERANCES
+12 0
+150
+18 0
+210
+250
+300
+350
+10 0
H7
h7 0-10
0-12
0-15
0-18
0-21
0-25
0-30
0-35
k10 +400
+480
+580
+700
+840
+1000
+1200
+1400
122
DIFFICULT TO MACHINE MATERIALS
There are number of materials which are generally regarded asbeing difficult to machine. In general terms the material beingworked is considered to be difficult when it does not respondreadily to normal machining techniques. Among these “difficult’materials are aluminium alloys, stainless steel and work harden-ing steels.
Aluminium Alloys require relatively high speeds and feeds.They respond best to cutters with few teeth and correspond-ingly wide chip spaces, and can be worked very effectively byusing two flute end mills, which have the advantage of fewerteeth engaged in the cut. In many cases coolant may not beneeded to cool the cutter although it is of benefit in lubricatingand particularly in removing chips. Climb milling gives definiteadvantages and shows significant benefits where a good qual-ity surface finish is needed. These materials can be workedquite effectively with regular tooling, although benefits wouldbe obtained from custom tools in the event of large volumeproduction being the norm.
Stainless Steels require lower speeds and higher feed ratesand often benefits are obtained from using corner radii andchamfers. These materials respond well to the conventionalcutting method but rigidity of machine and setup are critical.Light finishing cuts are to avoided but where necessary shouldbe taken at a feed rate as high as possible to meet with sur-face finishing requirements. It is crucial that these materials be“worked”, and “rubbing” of the cutter against the workpieceshould be avoided. Selection of speed and feed rates is ofgreat importance. Coolant must be used in large volume and bedirected at the cutting area. Benefits are often obtained from ahiger coolant concentration or from using cutting oils.
Work Hardening Steels such as some stainless and manga-nese steels can be successfully machined by using the sametechniques as described for stainless steels above.
123
RESHARPENING AND CARE OF MILLING CUTTERS
The productivity of a milling machine depends to a large degreeon the efficiency of the milling cutter. Best results in both produc-tion and cutter life are obtained by sharpening cutters correctlyand carefully, and by taking proper care in handling and storage.A correctly sharpened cutter requires less driving power, pro-duces better quality work and gives longer service than an in-correctly or hastily sharpened cutter.
The following factors should be considered:-
Correct handling and storage to prevent damage.
Restoration of the cutting edges to their original geometry usingcorrect procedures.
Suitable wheel selection to ensure correct surface finish andstock removal. Consult wheel suppliers for specific recommen-dations.
Remember that milling cutters are precision tools and must behandled carefully. Damage due to incorrect handling or storagecan be seen as a flaw upon the milled surface of a workpiece.Grinding should be needed only as a result of dulling due to use.Regrinding to remove damage caused by rough handling mustbe considered to be a wasted process which reduces the life ofa cutter.
Correct clearance angles and radial rakes can be obtained fromdata given on page 104-107.
Primary
Secondary
RadialRake
124
GENERAL INFORMATION
INCH-MILLIMETER CONVERSION TABLE
3"mm
76.20076.59776.99477.39177.78878.18478.58178.97879.37579.77280.16980.56680.96281.35981.75682.15382.55082.94783.34483.74184.13884.53484.93185.32885.72586.12286.51986.91687.31287.70988.10688.503
2"mm
50.80051.19751.59451.99152.38852.78453.18153.57853.97554.37254.76956.16655.56255.95956.35656.75357.15057.54757.94458.34158.73859.13459.53159.92860.32560.72261.11961.51661.91262.30962.70663.103
1"mm
25.40025.79726.19426.59126.98827.38427.78128.17828.57528.97229.36929.76630.16230.59930.95631.35331.75032.14732.54432.94133.33833.73434.13134.52834.92535.32235.71936.11636.51236.90937.30637.703
0"mm
0.3970.7941.1911.5881.9842.3812.7783.1753.5723.9694.3664.7625.1595.5565.9536.3506.7477.1447.5417.9388.3348.7319.1289.5259.92210.31910.71611.11211.50911.90612.303
0 . . . . .1/64 . . . .1/32 . . . .3/64 . . . .1/16 . . . .5/64 . . . .3/32 . . . .7/64 . . . .1/8 . . . . .9/64 . . . .5/32 . . . .11/64 . . . .3/16 . . . .13/64 . . . .7/32 . . . .15/64 . . . .1/4 . . . . .17/64 . . . .9/32 . . . .19/64 . . . .5/16 . . . .21/64 . . . .11/32 . . . .23/64 . . . .3/8 . . . . .25/64 . . . .13/32 . . . .27/64 . . . .7/16 . . . .29/64 . . . .15/32 . . . .31/64 . . . .
125
INCH-MILLIMETER CONVERSION TABLE (cont)
3"mm
89.90089.29789.69490.09190.48890.88491.28191.67892.07592.47192.86892.26693.66294.85994.45694.85395.25095.64796.04496.44196.83897.23497.63198.02898.42598.28299.01999.616100.012100.409100.806101.203
2"mm
63.50063.89764.29464.69165.08865.48465.88166.27866.67567.07167.46867.86668.26268.85969.05669.45369.85070.24770.64471.04171.43871.83472.23172.62873.02573.42273.01974.21674.61275.00975.40675.803
1"mm
38.10038.49738.89439.29139.68840.08440.48140.87841.27541.67142.06842.46642.86243.85943.65644.05344.45044.84745.24445.64146.03846.43446.83147.22847.62548.02248.01948.81649.21249.60950.00650.403
0"mm
12.70013.09713.49413.89114.28814.68415.08115.74815.87516.27116.66817.06617.46217.85918.25618.65319.05019.44719.84420.24120.63821.03421.43121.82822.22522.62223.01923.41623.81224.20924.60625.003
1/2 . . . . .33/64 . . . .17/32 . . . .35/64 . . . .9/16 . . . .37/64 . . . .19/32 . . . .39/64 . . . .5/8 . . . . .41/64 . . . .21/32 . . . .43/64 . . . .11/16 . . . .45/64 . . . .23/32 . . . .47/64 . . . .3/4 . . . . .49/64 . . . .25/32 . . . .51/64 . . . .13/16 . . . .53/64 . . . .27/32 . . . .55/64 . . . .7/8 . . . . .57/64 . . . .29/32 . . . .59/64 . . . .15/16 . . . .61/64 . . . .31/32 . . . .63/64 . . . .
126
APPROXIMATE HARDNESS AND TENSILESTRENGTH CONVERSIONS
TENSILE STRENGTH
MPa orN/mm²
HRB HRC HV HB Tons/inch²
50556065707580859095100——————————————————————————
——————————202224262830323436384042444648505254565860646668707580
95100110120130140150165185205230240255265280295310325345360380405425450480505545580615655695790855940107514801865
90100105110120130140160175195220230240250265280290310325345365385405430455480———————————
212325272931343740455053565962656872757883889296102108112117122130135150163179197——
32035039042015018052057062069077082086091096010001050111011501200128013601420148015401670172018001890200021002320251027703030——
HRB = Hardness Rockwell BHRC = Hardness Rockwell CHV = Hardness Vickers. Also DPN, VPN, DPH, VPHHB = Hardness Brinell. Also BHNNote:These values should be treated as approximate only and are suitablefor calculating speeds and feeds or for general information purposes.Do not use for treated high speed steel.
127
HARDNESS CONVERSION CHART FORHIGH SPEED STEEL
HV30 HRC HV30 HRC
736741746752757763769775780786792798804810817823829836842849
59-3/460
60-1/460-1/460-1/2
6161
61-1/461-1/261-3/4
6262-1/462-1/262-3/4
6363-1/463-1/263-3/4
6464-1/4
856862869876883890897905912919927934942950958966974982990999
64-1/263-3/4
6565-1/465-1/2
6666
66-1/26767
67-1/467-1/2
6868
68-1/268-1/2
6969-1/269-1/2
70
Typical hardness
M2 823-876 HV30 - 63-65 HRCM35 849-920 HV30 - 64-66 HRCM42 897-966 HV30 - 66 - 68-1/2 HRC
Depending on the nature of the tool these hardnesses may be varied,particularly in the case of special tools where different hardnessesmay be specified.
Note:Undue reliance should not be placed on a general conversion chartunless it has been tested for a particular material. The above chartapplies specifically to High Speed Steel.
128
Section EUSEFUL FORMULAE
Trigonometry
Formulae for the solution of Formulae for the solution ofRIGHT ANGLED OBLIQUE ANGLEDTRIANGLES TRIANGLES
A
B C
cb
a
qqqqq
A
B C
c
a
b
Tan q q q q q =
Sin q q q q q =
Cos q q q q q =
oppositeadjacent
oppositehypotenuse
adjacenthypotenuse
=
=
=
ca
cb
ab
The Sine rule: a b cSin A Sin B Sin CThe Cosine rule:a² = b² + c² - 2bc Cos Ab² = a² + c² - 2ac Cos Bc² = a² + b² - 2ab Cos C
= =
USEFUL VALUES IN TRIGNOMETRICAL RATIOSFor right angled triangles
60°
30°
12
45°
45°1
1Ö3
Ö2
ANGLES 30° - 45° - 60°
qqqqq Tan qqqqq Sin qqqqq Cos qqqqq
30°
45°
60°
13
12Ö = 0.577350 = 0.500000
32
Ö= 0.866025
1 12Ö = 0.707107
12Ö = 0.707107
3 = 1.732051Ö 32
Ö= 0.866025
12 = 0.500000
129
Useful formulae for FindingDimensions of Circles, Squares, etc.
D is diameter of stock necessary to turn shape desired.E is distance “across flats,” or diameter of inscribed circle.C is depth of cut into stock turned to correct diameter.
C
E
D
CE
D
CE
D
CE
D
C
E
D
TRIANGLE
E = side x 0.57735D = side x 1.1547 = 2ESide = D x 0.866C = E x 0.5 = D x 0.25
SQUARE
E = side = D x 0.7071D = side x 1.4142 = diagonalSide = D x 0.7071C = D x 0.14645
PENTAGON
E = side x 1.3764 = D x 0.809D = side x 0.7013 = E x 1.2361Side = D x 0.5878C = D x 0.0955
HEXAGON
E = side x 1.7321 = D x 0.866D = side x 2 = E x 1.1547Side = D x 0.5C = D x 0.067
OCTAGON
E = side x 2.4142 = D x 0.9239D = side x 2.6131 = E x 1.0824Side = D x 0.3827C = D x 0.038
130
Areas ofPlane Figures
a² - ( )12
s
s
d
d
b
a
c
b
a
c
b
a
hbh2 =
b2 Ö
a² + b² - c²2b
²
SQUARE
A = areaA = S² = 1/2 d²S = 0.7071d = ÖAd = 1.414S = 1.414 ÖA
RECTANGLE
A = areaA = ab = a Öd² - a² = b Öd² - b²d = Öa² + b²a = Öd² - b² = A ÷ bb = Öd² - a² = A ÷ a
RIGHT ANGLED TRIANGLE
A = areaA = bc 2a = Öb² + c²b = Öa² - c²c = Öa² - b²
ACUTE ANGLED TRIANGLE
A = area
A =
if S = ( a + b + c ) then,
A = ÖS(S -a) (S - b) ( S - c)
131
OBTUSE ANGLED TRIANGLE
A = area
A =
if S = ( a + b + c ) then,
A = ÖS(S -a) (S - b) ( S - c)
CIRCLE
A = area C = circumferenceA = p r² = 3.1416 r²
A = = 0.7854 d²
C = 2 pr = 6.2832r = 3.1416d
r = C ÷ 6.2832 = ÖA ÷ 3.1416 = 0.564 ÖA
d = C ÷ 3.1416 = ÖA ÷ 0.7854 = 1.128 ÖA
REGULAR HEXAGON
A = areaR = radius of circumscribed circler = radius of inscribed circleA = 2.598S² = 2.598R² = 3.464r²R = S = 1.155rr = 0.866S = 0.866R
bh2 = a² - ( )
Öc² - a² - b²
2b
²
12
b2
c
b
a
rd
h
r
60°R
s
p d²4
The construction of a regular hexagon forms six equilateral triangles,thusthe area of the hexagon can also be found by calculating the area of theequilateral triangle and multiplying the result by six.
132
USEFUL FORMULAE
rpm = Surface Speed (metres/min) ÷Dia (mm) X p
1000
Surface Speed (metres/min) = X rpmDia (mm) X p
1000
Feed Rate (mm/rev) =Feed rate (mm/min
rpm
Penetration rate (mm/min) = rpm X feed rate (mm/rev)
133
Cone of Included Angle Angle with Centre Line
1 in 22-1/21 in 33-1/21 in 44-1/21 in 55-1/21 in 66-1/21 in 77-1/21 in 88-1/21 in 99-1/2
1 in 101 in 111 in 121 in 131 in 141 in 151 in 161 in 171 in 181 in 191 in 201 in 251 in 30 1 in 351 in 401 in 451 in 481 in 501 in 551 in 60
28°22°18°16°14°12°11°10°9°8°8°7°7°6°6°6°5°5°4°4°4°3°3°3°3°3°2°2°1°1°1°1°1°1°1°
4´37´55´15´15´40´25´23´31´47´10´37´9´
43´21´1´
43´12´46´24´5´
49´34´22´10´0´
51´17´54´38´25´16´11´8´2´
57´
20²12²28²38²0²50²16²20²36²52²16²43²10²58²34²32²31²18²19²16²26²6²48²9²58²54²52²31²36²14²56²24²37²46²29²17²
14°11°9°8°7°6°5°5°4°4°4°3°3°3°3°3°2°2°2°2°2°1°1°1°1°1°1°1°
2´18´27´7´7´
20´42´11´45´23´5´
48´34´21´10´0´
51´36´23´12´2´
54´47´41´35´30´25´8´
57´49´42´38´35´34´31´28´
10²36²44²49²30²25²38²40²48²56²8²52²35²59²47²46²46²9²9²8²43²33²24²4²29²27²56²46²18²7²58²12²48²23²14²39²
USEFUL TAPERS
134
MO
RS
E T
AP
ER
S A
ND
BR
OW
N &
SH
AR
PE
TA
PE
RS
Tape
rN
umbe
rTa
per
Per
mm
on
dia.
Tape
r P
erfo
ot o
n di
a.In
clud
ed A
ngle
Ang
le t
o C
entr
e Li
neD
eg.
Min
s.S
ecs
.D
eg.
Min
s.S
ecs
.
Mo
rse
1 2 3 4 5 6
Bro
wn
&S
har
pe
4 5 7 9 10 11 12
0.04
9881
0.04
9951
0.05
0196
0.05
1938
0.05
2626
0.05
2137
0.04
1867
0.04
1800
0.04
1789
0.04
1737
0.05
1343
0.04
1750
0.04
1644
0.59
858
0.59
941
0.60
235
0.62
326
0.63
151
0.62
565
0.50
240
0.50
160
0.50
147
0.50
085
0.51
612
0.50
100
0.49
973
2 2 2 2 3 2 2 2 2 2 2 2 2
51 51 52 58 0 59 23 23 23 23 27 23 23
27 41 31 31 52 12 54 41 39 28 50 30 08
1 1 1 1 1 1 1 1 1 1 1 1 1
25 25 26 29 30 29 11 11 11 11 13 11 11
43 50 16 15 26 36 57 50 49 44 55 45 34
135
Conversion Factors:British - MetricTo convert Multiply byInches to millimetres 25.40Feet to metres 0.3048Yards to metres 0.9144Miles to kilometres 1.60934Square inches to square centimetres 6.4516Square feet to square metres 0.092903Square yards to square metres 0.836127Square miles to square kilometres 2.58999Cubic inches to cubic centimetres 16.3871Cubic feet to cubic metres 0.028317Cubic yards to cubic metres 0.764555Pints to litres 0.568261Gallons to litres 4.54609Ounces to grams 28.3495Pounds to kilograms 0.453592Tons to tonnes (1.000kg) 1.01605Lb/sq.in. to kg/sq.m 703.070Fahrenheit = 9/5°C+32
Conversion Factors:Metric - BritishTo convert Multiply byMillimetres to inches 0.0393701Metres to feet 3.28084Metres to yards 1.09361Kilometres to miles 0.621371Square centimetres to square inches 0.1550Square metres to square feet 10.76391Square metres to square yards 1.19599Square kilometres to square miles 0.3861Cubic centimetres to cubic inches 0.061024Cubic metres to cubic feet 35.3147Litres to pints 1.76Litres to gallons 0.22Grams to ounces 0.035274Kilograms to pounds 2.20462Tonnes to tons 0.984207Kg/sq.mm to lb/sq.in. 0.001422Centigrade (Celcius) = 5/9° (F-32)
136
.1mm
.2mm
.3mm8079
1/64.4mm
7877
.5mm767574
.6mm737271
.7mm706968
1/32.8mm
676665
.9mm64636261
1mm6059585756
3/64555453
1/165251504948
5/6447
2mm46
Decimal Equivalentsmm-Inch-Wire
.0039
.0079
.0118
.0135
.0145
.0156
.0157
.0160
.0180
.0197
.0200
.0210
.0225
.0236
.0240
.0250
.0260
.0276
.0280
.0292
.0310
.0312
.0315
.0320
.0330
.0350
.0354
.0360
.0370
.0380
.0390
.0394
.0400
.0410
.0420
.0430
.0465
.0469
.0520
.0550
.0595
.0625
.0635
.0670
.0700
.0730
.0760
.0781
.0785
.0787
.0810
DecimalInch
mm-Inch-Wire
DecimalInch
mm-Inch-Wire
DecimalInch
mm-Inch-Wire
DecimalInch
45444342
3/32414039383736
7/6435343332
3mm311/8302928
9/642726252423
5/3222
4mm21201918
11/641716151413
3/161211109
5mm87
13/646
.0820
.0860
.0890
.0935
.0938
.0960
.0980
.0995
.1015
.1040
.1060
.1094
.1100.1110.1130.1160.1181.1200.1250.1285.1360.1405.1406.1440.1470.1495.1520.1540.1562.1570.1575.1590.1610.1660.1695.1719.1730.1770.1800.1820.1850.1875.1890.1910.1935.1960.1969.1990.2010.2031.2040
543
7/3221A
15/646mm
BCD
1/4 & EFG
17/64HI
7mmJK
9/32LM
19/64N
5/168mm
OP
21/64QR
11/32S
9mmT
23/64U
3/8VW
25/6410mm
XY
13/32Z
27/6411mm7/16
.2055
.2090
.2130
.2188
.2210
.2280
.2340
.2344
.2362
.2380
.2420
.2460
.2500
.2570
.2610
.2656
.2660
.2720
.2756
.2770
.2810
.2812
.2900
.2950
.2969
.3020
.3125
.3150
.3160
.3230
.3281
.3320
.3390
.3438
.3480
.3543
.3580
.3594
.3680
.3750
.3770
.3860
.3906
.3937
.3970
.4040
.4062
.4130
.4219
.4331
.4375
29/6415/3212mm31/641/2
13mm33/6417/3235/6414mm9/1637/6415mm19/3239/645/8
16mm41/6421/3217mm43/6411/1645/6418mm23/3247/6419mm
3/449/6425/3220mm51/6413/1621mm53/6427/3255/6422mm
7/857/6423mm29/3259/6415/1624mm61/6431/3225mm63/64
1”
.4531
.4688
.4724
.4844
.5000
.5118
.5156
.5313
.5469
.5512
.5625
.5781
.5906
.5938
.6094
.6250
.6299
.6406
.6562
.6693
.6719
.6875
.7031
.7087
.7188
.7344
.7480
.7500
.7656
.7812
.7874
.7969
.8125
.8268
.8281
.8438
.8594
.8661
.8750
.8906
.9055
.9062
.9219
.9375
.9449
.9531
.9688
.9843
.98441.0000
NUMBER AND LETTER DRILL SIZES
137
NOTES
138
NOTES
139
NOTES
140
NOTES
ISO
9 001
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