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COMPRESSION LIMITERS

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Our objective is to provide our customers with the best value — for optimum performance at the lowest installed cost. To achieve this objective, our sales strategy focuses on the application engineering approach.

Starting with an analysis of your needs and objectives, our application engineers determine the best SPIROL® COMPRESSION LIMITER for the application. Consideration is not only given to the Compression Limiter but also to the specifications of the components to be assembled and potential assembly problems. Recommendations and samples are provided for your evaluation.

The versatility of the SPIROL® COMPRESSION LIMITER makes it the ideal component part to meet the specific engineering and economic objectives of plastic assemblies. Our range of standard Compression Limiters is designed to meet most requirements. If a special diameter, length, duty, material, tolerance or configuration is needed, we are ready to assist you.

Challenge us!

THE SPIROL CONCEPT

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THE FUNCTION OF A COMPRESSION LIMITER

Compression Limiters are designed to protect the plastic components of an assembly from the compressive loads generated by the tightening of bolts, thereby assuring continued integrity of the bolted connection.

In practice, as the bolt is tightened the plastic compresses and the stress in the plastic increases until the head of the bolt, or washer if one is used, comes into contact with the Compression Limiter. Thereafter, the Compression Limiter and plastic will compress at the same rate. The Compression Limiter will absorb additional clamping loads without further significant compression and increased stress in the plastic material.

A properly designed bolted joint must meet the following criteria:• The head of the bolt, or washer if one is used, should

always seat against the Compression Limiter under load. This will prevent deterioration of the bolted joint resulting from diminished clamping load due to plastic creep.

• The proof load of the Compression Limiter should be equal to or greater than the proof load of the bolt to assure that the Compression Limiter will not yield prior to the bolt under excessive clamping loads.

• The mating component that the Compression Limiter seats against should be strong enough to withstand the localized compressive stresses generated by the clamping force.

• The clearance between the maximum bolt diameter and the minimum installed inside diameter of the Compression Limiter should be sufficient to compensate for normal misalignment.

Standard SPIROL® COMPRESSION LIMITERS meet these criteria.

The clearance between the bolt and the inside diameter of the installed Compression Limiters is adequate to meet normal misalignment. The length and length tolerance is application dependent. The standard tolerance is sufficient to meet most needs, but verification is recommended. SPIROL Engineering is available to assist in this process. If it is determined that a special Compression Limiter is required, a documented recommendation will be provided.

The SPIROL range of Compression Limiters includes the molded-in, split seam and solid knurled designs. The molded-in type is produced from low carbon steel and is equipped with radial grooves to provide maximum retention. The split seam type is produced from low carbon and high carbon steel. The solid knurled type is produced from brass and aluminum. Since these Compression Limiters are designed to meet specified proof loads, the dimensional specifications are different. The split seam design has a lead-in to facilitate insertion. The solid design has a pilot, allowing it to stand freely in the hole prior to complete installation.

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DESIGN CONSIDERATIONS

Recommended LoadingThe integrity of a bolted joint requires that all of the components in the load path be capable of sustaining for indefinite periods, under all environmental conditions, the fastening load initially applied. To do this, all components must be designed for a specific stress, and the fastener being used must be tightened to an appropriate level so as not to exceed the yield point (elastic limit) of any of the components. The reason that metal Compression Limiters are required is because plastic always exhibits stress and strain relaxation under even modest loads. When determining bolted joint characteristics, the following considerations should be evaluated:

• What type of load is really required? For example, does a given plastic flange really need a Class 12.9 cap screw to hold it in place?

• What are the strengths of the components in the joint?

• What will the Compression Limiter be seated against? If it is aluminum or plastic, then that may be the limiting feature.

• Is the bolt being threaded into an Insert? If so, is there adequate thread strength and contact area on the Insert to fully support the Compression Limiter?

• What torque should the bolt be tightened to? SPIROL recommends that the bolt load be 25% to 75% of proof load. Less than 25% and you risk not generating enough frictional retention within the threads. More than 75% and there is a chance due to assembly variations that proof load of the bolt may be exceeded.

• How does torque relate to bolt load? Torque and actual clamping load are very dependant on materials and conditions. The theoretical formula provided on page 9 is only for reference. Actual torque applied must be determined by the end user and is dependant on a variety of factors such as materials and coatings of all the components in the joint as well as the method of applying the torque.

Recommended Tightening TorqueThe integrity of the bolted joint requires that none of the components, including the bolt, be stressed beyond the elastic limit. We recommend a clamping load equal to 75% of the proof load of the bolt. The recommended torque values to produce this clamping load are provided on pages 8 and 9.

Determination of Compression Limiter LengthProper length specifications of both the Compression Limiter and the plastic component are crucial to the proper performance of the bolted joint. The recommended maximum length of the Compression Limiter is the minimum thickness of the plastic component. This assures that when the proper load is applied to the bolt two critical conditions will be met:

• The bolt will be in contact with the Compression Limiter, eliminating the possibility of creep.

• The plastic host will always have a small amount of compression applied.

The amount of compression on the plastic host will be at most the combined thickness and length tolerances of the two components and the amount of compressive deflection on the Compression Limiter. In reality, with good SPC and production controls, the actual compression will be much less.

Allowable Compression of the Plastic ComponentFor most commonly used molded plastics, it is difficult to determine a specific maximum amount that they can be compressed in a short period of time. There are too many variables involved to make an specific calculation. Such features as the specific plastic, filler, mold design, wall thickness, and stress concentrations all impact the durability of the plastic. As a general guideline, 2%-3% compression of thermoplastic materials is reasonable. Over a short period of time the plastic will usually exhibit stress relaxation, thereby alleviating the compressive load on the plastic and allowing the Compression Limiter to maintain joint integrity. Stated in formula (1) below:

(1) DP = Tmax - Lmin + DC

Where DP should typically be less than 3% of Tmax Where: DP = Required deflection of the plastic component, in units of length.Tmax = Maximum thickness of the plastic component, in units of length.Lmin = Minimum length of the Compression Limiter, in units of length.DC = Deflection of the Compression Limiter under load, in units of length.

Deflection of the Compression Limiter under bolt load can be calculated using formula (2) below:

(2) DC =

Where: DC = Deflection of the Compression Limiter under load, in units of length.FB = Compressive force generated by the bolt or fastener, in units of force.LC = Nominal length of the Compression Limiter, in units of length.AC = Cross sectional area of the Compression Limiter, in units of area.EC = Modulus of Elasticity (Young’s Modulus) of the material of the Compression Limiter, in units of force per area. See Table 1.

FB x LC

AC x EC

psi30,000,00028,000,00029,000,00015,000,00010,000,000

MaterialCarbon SteelSST (Austenitic)SST (Martensitic)BrassAluminum

N/mm² (MPa) 206,000 193,000 200,000 103,000 69,000

Table 1 - Modulus of Elasticity for Common Materials

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Table 2 - Deflection Factor C at Proof Load

Stainless(Austenitic)Carbon Steel Stainless

(Martensitic)Bolt

Class / GradeCompressionLimiter Series Brass Aluminum

0.001700.002450.00135

0.001600.002300.00125

0.001650.002350.00130

Class 8.8Class 10.9

Class 5.8 / Grade 2

CL300 / CL500CL350

CL101 / CL111

0.003200.004550.00255

0.004750.006850.00380

The values for the Deflection Factor C listed in Table 2 are used to simply estimate the actual maximum deflection a Compression Limiter will exhibit when fully loaded to the specified fastener’s proof load. Formula (3) uses C and the nominal length of the Compression Limiter to calculate deflection.

(3) DC = C x LC

For deflections at loads other than proof, the results are proportional to the loading.

Force to Seat the Bolt on the Compression LimiterIt is important to always assure that the bolt is seated hard against the Compression Limiter. While proportionally plastic is much more compressible than the Compression Limiter, in the initial assembled state the plastic will be nominally thicker than the length of the Compression Limiter. With the use of flanged bolts or large washers, significant surface area of the plastic can be put under compression, generating high loads. Therefore, it is necessary to calculate the capability of the bolt to compress the plastic and seat against the Compression Limiter in the worst case scenario. Formula (4) shows how to calculate the force required to seat the bolt.

(4) FB =

Where AP =

Where: FB = Compressive force generated by the bolt or fastener, in units of force.Tmax = Maximum thickness of the plastic component, in units of length.Lmin = Minimum length of the Compression Limiter, in units of length.EP = Modulus of Elasticity (Young’s Modulus) of the plastic component, in units of force per area.AP = Area of the plastic component being placed in compression by the bolt, in units of area.D1 = Minimum hole diameter of the plastic component, in units of length.D2 = Maximum diameter of the portion of the bolt or washer that will be in contact with the plastic, in units of length.

The resultant FB should be in the range of 50% or less of the proof load of the selected bolt, thereby assuring that sufficient compression is applied to the Compression Limiter after the plastic stress has relaxed.

Headed Compression LimitersIn addition to providing a larger contact area, headed Compression Limiters eliminate the need for a washer. The length and length tolerance under the head needs to be determined following these design guidelines for Compression Limiters to avoid the risk of exceeding the elastic limit of the plastic component. Headed Compression Limiters are only available as solid components because of the tolerances required for proper Compression Limiter operation.

Hole DesignAlthough the split seam Compression Limiters have a broken edge, this is kept to a minimum in order to maintain the maximum bearing surface area. Accordingly, it is recommended that a radius be molded as a lead-in to the hole in the plastic component to facilitate insertion. This radius is not necessary for solid Compression Limiters as the pilot is smaller than the hole. When a draft angle is required, the hole should taper within the recommended hole size for the length of the Compression Limiter.

π x ( D22 - D1

2 )4

( Tmax - Lmin ) x EP x AP

Tmax

Mating Component MaterialThe clamping load of the bolt is transferred to the mating component through the Compression Limiter. It must be evaluated whether the material of the mating component is strong enough to withstand the clamping force of the bolt. The stress imparted onto the mating component can be calculated by dividing the clamping load applied to the Compression Limiter by the cross sectional area of the Compression Limiter. If this stress exceeds the yield strength of the mating component material, localized permanent deformation may occur, resulting in a loss in clamping load.

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The weakest sections of most plastic assemblies are the joints and assembly points. During the assembly of mating components, the screw has to be tightened with sufficient torque to produce the recommended axial tension load between the host component and the threads of the screw in order to prevent loosening. A common problem with bolted joints is that plastics are susceptible to creep or stress relaxation as displayed in the drawing on the right. Under loads well below the elastic limit, plastics will lose their ability to maintain a load. When this occurs, the threaded connection becomes loose.

In applications where the mating component i s a lso p las t i c , Threaded Inserts may be used in conjunction with Compression Limiters to enable the appropriate installation torque to be applied to the screw without stripping the threads in the plastic assembly.

Metal threaded Inserts significantly improve joint strength in plastic parts and are not themselves susceptible to creep. The larger

body diameter and body design of the Insert allow the appropriate installation torque to be applied to the screw. These joints do not become loose over time since the brass provides permanent creep resistance for the entire load path of the thread. Additionally, the Inserts enable unlimited assembly/disassembly of the components without compromising the integrity of the threads.

It is essential for the Compression Limiter to be in contact with the Insert. The Insert – and not the plastic – must carry the load. Otherwise the Insert will tend to want to pull out of the plastic as the bolt is torqued. This condition is called jack-out and under no circumstance is this acceptable.

MATING COMPRESSION LIMITERS AND THREADED INSERTS

In applications using multiple Inserts where misalignment needs to be accommodated, the standard solution is to increase the clearance between the internal diameter of the Compression Limiter and the external diameter of the assembly screw. This obviously has the potential of the Compression Limiter not aligning satisfactorily with the Insert. In these situations a Headed Insert is always recommended. Consideration can also be given to increasing the wall thickness of the Compression Limiter.

If the pilot diameter of the Insert being used is too small for the inside diameter of the Compression Limiter, then a special Compression Limiter with reduced clearance between the assembly screw may resolve the problem. This of course also reduces permissible misalignment.

If the surface area of the Insert is inadequate for proper contact with the Compression Limiter, then the only solution is using a plastic in the mating component which has good anti-creep characteristics and using a Compression Limiter with maximum wall thickness for better distribution of the load. Jack-out in these situations will be a concern and needs to be addressed by avoiding over-torquing of the assembly screw.

SPIROL® Series 16, 20, 25, 28, 30 and 51 Insertsfor Plastic Assemblies

SPIROL® Series 14, 19, 24, 41 and 45 Insertsfor Plastic Assemblies

Proper configuration

Plastic creep

Jack-out

The surface area of SPIROL’s Series 14, 19, 24, 41 and 45 Inserts is more than adequate for most applications.

For increased surface contact between the Insert and the Compression Limiter, Design Engineers may choose to incorporate one of the headed Insert Series 16, 20, 25, 28, 30 or 51.

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COMPRESSION LIMITERS SPECIFICATIONS

SERIES CL500

MATERIAL FINISHF Low Carbon Steel T Trivalent Zinc Plated

* Intermediate lengths, longer lengths, and tight length tolerance products available on request and feasibility review.

• Inch sizes available upon special request.• Rated for use with ISO Class 8.8 bolts.

DIMENSIONAL DATA

ID min.Nominal

Bolt Diameter

9.912.9

6.88.8

M6M8

T L*Metric

OD1.52.0

4 6 8 10 12 15 20 30 40 50

L

T NOM

øODRef. Only

øID MIN.BREAK EDGE (0.25) TYP

+0-0.2

To Order: SPCR, Nominal Bolt Size x Length, Material, Finish, SeriesExample: SPCR 6 X 20 FT CL500

STANDARD MOLDED-IN

Plastic removed to show Compression

Limiter.

Features and Benefits:

• OD vertical grooves at the seam offer an anti-rotational feature.

• Lead-in ID chamfer increases feeding and positioning speed as well as efficiency in automated

pick-and-place applications.

• Designed around standard, industry-accepted clearances for M6 and M8 bolts.

SPIROL®

Standard Molded-In Compression Limiters can be molded in using industry standard core pins.

Parts less than 20 mm long will have a single groove.

6

L

T

ØOD

+0-LTol

SPIROL®

Standard Split Seam Compression Limiters can be simply pressed in.

To Order: BUSH, Nominal Bolt Diameter, Length, Material, Finish, SeriesExample: BUSH 6 X 50 BK CL350

STANDARD SPLIT SEAM

DIMENSIONAL DATA

SERIES CL350High Carbon Steel

SERIES CL300Low Carbon Steel

* Longer and shorter lengths on request.• CL300 rated for use with ISO Class 10.9 bolts.• CL350 rated for use with ISO Class 12.9 bolts.

COMPRESSION LIMITERS SPECIFICATIONS

Features and Benefits:

• Flexible diameter accommodates wide

hole tolerances.

• Lead-in facilitates insertion.

• Offered in low carbon and high carbon steel versions to suit various bolt grades.

• Designed to avoid witness marks on soft

mating materials.

MATERIAL FINISHF Low Carbon Steel K PlainB High Carbon Steel T Zinc Plating w/ Trivalent Clear Chromate

Nominal Bolt Ø

Ø7.08/7.22Ø8.28/8.45

Ø10.08/10.28Ø13.25/13.52Ø16.25/16.58Ø19.30/19.69

1.01.11.52.02.53.0

RecommendedØ Hole Size

Ø6.95/7.05Ø8.15/8.25Ø9.95/10.05Ø13.05/13.20Ø16.05/16.20Ø19.10/19.25

Ø4.8Ø5.8Ø6.8Ø8.8Ø10.8Ø12.8

M4M5M6M8M10M12

5 to 258 to 258 to 5010 to 5012 to 5012 to 50

L*Ø ODMin. Ø ID Installed

Metric

T0.150.150.150.150.250.25

LTol

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SPIROL®

Standard Solid Knurled Compression Limiters can be molded in or simply pressed in.

Features and Benefits:

• Square ends - to ensure 100% contact

with mating surface

• Series CL111 (Headed) - eliminates the need for a washer

• Knurl - provides excellent retention

• Aluminum is lightweight and contains no lead

STANDARD SOLID KNURLEDSERIES CL101 SERIES CL111

Headed

Parts less than .375” (10 mm) long will have the second knurl band omitted.

L

T

C REFøH øB øAøA

L

øB C REF

MATERIAL FINISHA Aluminum K PlainE Brass

DIMENSIONAL DATA

* Longer and shorter lengths on request.• Designed for use with SAE Grade 2 and ISO Class 5.8 bolts.

Inch

Ø.238Ø.269Ø.300Ø.342Ø.435Ø.529

Ø.188Ø.219Ø.250Ø.292Ø.385Ø.479

.050

.050

.050

.050

.050

.050

Ø.145Ø.168Ø.196Ø.223Ø.282Ø.345

#4#6#8#10.250.312

.118-.394

.187-.500

.187-.562

.236-.687

.236-.812

.236-.812

Ø.195Ø.226Ø.257Ø.299Ø.392Ø.486

A HNominal Bolt Size TB L*

+0/-.006Hole±.002

Ø.200Ø.231Ø.262Ø.304Ø.397Ø.491

C

ANominal Bolt Size

Ø4.80Ø5.55Ø6.35Ø7.65Ø9.00Ø12.15

Ø3.70Ø4.25Ø5.00Ø5.75Ø6.75Ø8.75

M3M3.5M4M5M6M8

B H TØ6.05Ø6.85Ø7.60Ø8.95Ø10.25Ø13.45

1.301.301.301.301.301.30

3.0-10.04.0-12.05.0-14.06.0-16.06.0-20.06.0-20.0

Ø4.90Ø5.70Ø6.50Ø7.80Ø9.10Ø12.30

L*+0/-0.15

Hole+0.10/-0.00

Metric

Ø5.10Ø5.85Ø6.65Ø8.00Ø9.30Ø12.45

C

COMPRESSION LIMITERS SPECIFICATIONS

Plastic removed to show Compression

Limiter.

To Order: SPCR, Nominal Bolt Size x Length, Material, Finish, SeriesExample: SPCR #6 X .500 AK CL101

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BOLT SPECIFICATIONS

Notes:• Proof loads are per SAE J429 and ISO 898 respectively.• Shaded inch sizes are not directly covered by SAE J429, but are calculated appropriately.• Clamp load is approximately 75% proof load.

Common Inch Bolts per SAE J429

Proof

Threads

510770

1,1901,4802,7004,4506,600

250375575720

1,3102,2003,200

380580895

1,1102,0253,3404,950

540820

1,2601,5752,8504,7257,000

330500770960

1,7502,9004,250

#4-40#6-32#8-32#10-241/4-205/16-183/8-16

Clamp720

1,0901,6802,1003,8006,3009,300

Grade 2 Loads (lbs.) Grade 5 Loads (lbs.) Grade 8 Loads (lbs.)

Coarse Proof Clamp Proof Clamp

Common Inch Bolts per SAE J429

Proof

Threads

560860

1,2501,7003,1004,9007,450

270410600825

1,5002,4003,600

420645940

1,2752,3253,6755,600

600910

1,3201,8003,2605,2107,900

360550800

1,1002,0003,2004,800

#4-48#6-40#8-36#10-321/4-285/16-243/8-24

Clamp790

1,2101,7602,4004,3506,950

10,500

Grade 2 Loads (lbs.) Grade 5 Loads (lbs.) Grade 8 Loads (lbs.)

Fine Proof Clamp Proof Clamp

85,000 psi120,000 psi380 N/mm²580 N/mm²830 N/mm²970 N/mm²

Standard Fastener RatedYield (Proof) Strengths

SAE Grade 5SAE Grade 8ISO Class 5.8ISO Class 8.8ISO Class 10.9ISO Class 12.9

Common Metric Bolts per ISO 898

ProofThreads

2,9203,9405,1008,230

11,60022,70021,20037,40035,50033,70053,40051,10048,900

1,4301,9402,5004,0505,750

11,20010,40018,40017,50016,50026,30025,10024,000

2,1902,9603,8506,1508,700

17,00015,90028,10026,60025,30040,10038,30036,700

3,1404,2205,4508,850

12,55024,40022,80040,10038,10036,10057,30054,80052,500

1,9102,5803,3405,4007,640

14,90013,90024,50023,30022,00035,00033,50032,000

M3M3.5M4M5M6M8 X 1M8 X 1.25M10 X 1M10 X 1.25M10 X 1.5M12 X 1.25M12 X 1.5M12 X 1.75

Clamp4,1805,6307,290

11,80016,70032,50030,40053,50050,80048,10076,40073,10070,000

Class 5.8 Loads (N) Class 8.8 Loads (N) Class 10.9 Loads (N)

Proof Clamp Proof Clamp Proof Clamp

Class 12.9 Loads (N)

3,6604,9406,400

10,35014,65028,50026,60047,00044,60042,20067,00064,10061,400

4,8806,5808,520

13,80019,50038,00035,50062,70059,40056,30089,30085,50081,800

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TORQUE SPECIFICATIONS

Notes:• Shaded inch sizes are not directly covered by SAE J429, but are calculated appropriately.• Torque for inch threads are in•lbs.• Torque for metric threads are N•m.• Torque values shown are for clamp load.• Actual loads developed by a specified torque value can vary by ±25%.

Common Inch Bolts per SAE J429

Dry

Threads

8.516.029.442.2

101.0209.0371.0

4.27.8

14.120.549.0

103.0180.0

6.412.022.031.676.0

157.0278.0

9.117.031.045.0

107.0221.0394.0

5.610.418.927.465.5

138.0240.0

#4-40#6-32#8-32#10-241/4-205/16-183/8-16

Lube12.122.641.360.0

143.0295.0525.0

Grade 2 Torque Grade 5 Torque Grade 8 Torque

Coarse Dry Lube Dry Lube

Common Inch Bolts per SAE J429

Dry

Threads

9.417.830.848.5

116.0230.0420.0

4.58.5

14.823.556.5

113.0202.0

7.113.423.136.387.0

172.0315.0

10.118.832.551.5

122.0244.0444.0

6.011.319.731.475.0

150.0270.0

#4-48#6-40#8-36#10-321/4-285/16-243/8-24

Lube13.425.143.368.5

163.0326.0593.0

Grade 2 Torque Grade 5 Torque Grade 8 Torque

Fine Dry Lube Dry Lube

T = K x D x P

Where:K = torque-friction coefficientD = nominal bolt diameterP = bolt clamping loadKDry = 0.2KLube = 0.15

Typical tightening torque values to achieve recommended Clamping Loads are based on the following formula:

Common Metric Bolts per ISO 898

DryThreads

1.32.13.16.2

10.427.225.456.253.250.696.291.988.1

0.61.01.53.05.2

13.412.527.626.324.847.345.243.2

1.01.62.34.67.8

20.419.142.139.938.072.268.966.1

1.42.23.36.6

11.329.327.460.257.254.2

103.198.694.5

0.91.42.04.06.9

17.916.636.835.033.063.160.257.6

M3M3.5M4M5M6M8 X 1M8 X 1.25M10 X 1M10 X 1.25M10 X 1.5M12 X 1.25M12 X 1.5M12 X 1.75

Lube1.93.04.48.8

15.139.036.580.276.272.2

137.5131.5126.0

Class 5.8 Torque Class 8.8 Torque Class 10.9 Torque

Dry Lube Dry Lube Dry Lube

Class 12.9 Torque

1.62.63.87.8

13.234.231.970.566.963.3

120.6115.4110.5

2.23.55.1

10.317.645.642.694.089.284.4

160.8153.8147.4

4© 2011 Spirol International Corporation 2.5M 04/11

ISO/TS 16949:2009 CertifiedISO 9001:2008 Certified

A manufacturer of automotive ignition coils approached SPIROL seeking a cost effective alternative to a machined brass Compression Limiter. Preferred method of installation was molded in. Compression Limiters were required to protect the integrity of the plastic case when bolting to the mating component. Three limiters were required per coil, one of which would protrude from the base to double as an alignment feature. For this reason, the end customer specified a high retention value to ensure the protruding Compression Limiter maintain its position.

The elimination of brass offers the most significant cost savings. Steel can provide the necessary strength at a much lower cost. Compression Limiters can be manufactured from low or high carbon steel and delivered soft or hard dependent upon fastener grade. Method of manufacture is the second component of cost that can be reduced. Machining or cutting operations are typically more expensive than forming. The best way to reduce the customer’s cost was to convert them from the machined brass component to a roll formed steel Compression Limiter.

SPIROL Engineering designed a rolled steel Compression Limiter to meet the customer’s specific requirements. The Compression Limiter was designed with a closed seam to ensure that plastic could not migrate to the ID where it may interfere with bolt installation. Wall thickness was selected to provide columnar strength sufficient to resist the compressive load of a Class 8.8 bolt. A radial groove was added about the part's circumference and centered. The radial groove fills with host material during the molding process that yields high resistance to lateral movement.

SPIROL’s roll formed steel Compression Limiter provided a substantial cost reduction while meeting all of the performance requirements. Roll formed Compression Limiters are typically designed to function with Class 8.8 bolts. A variety of finishes can be provided to meet specific requirements. The retention groove provides excellent resistance to lateral movement at significantly less cost than machined components with similar features. Steel complies with current environmental standards/content restrictions. Further, steel reduces the effect of galvanic corrosion when placed in contact with magnesium. Galvanic corrosion is common in assemblies where brass and magnesium are in direct contact due to the electric field generated by the coil packs.

Application:Automotive Ignition Coil

SOLUTIONENGINEERING

SPIROL Application Engineers will review your application needs and work with your design team to recommend the best solution. One way to start the process is to select Compression Limiters in our Optimal Application Engineering portal at www.SPIROL.com.

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Spirol SAS en España08940 Cornellà de LlobregatBarcelonaSpainTel. +34 93 193 05 32Fax. +34 93 193 25 43

Spirol S.A.S., organizační složka Sokola Tůmy 743/16Ostrava-Mriánské Hory 70900Czech RepublicTel/Fax. +420 417 537 979

Spirol International EngineeredFastener Trading Co. Ltd.No. 11 Xi Ya Rd. NorthSection A, 1F, Building 14Wai Gao Qiao Free Trade ZoneShanghai, China 200131Tel. +86 21 5046-1451/1452Fax. +86 21 5046-1540

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