We can put different shapes on the High speed tool bits to cut different shapes on the workpiece

The shape of the tool and the angles of its ground faces will depends on:

The operation to be performed The material which has to be machined The power & rigidity of the lathe The amount of material to be removed The quality of finish desired.

Tool holders

Used for holding cutting tool bits

Available in Right hand, left hand and straight

Carbon Steels High Speed Steel (HSS) Stellite Carbides Diamond

Carbon steels start to soften at a temperature of about 180oC. This limitation means that such tools are rarely used for metal cutting operations. widely used for woodworking and they can be used in a router to machine aluminum sheet up to about 3mm thick.

HSS tools are so named because they were developed to cut at higher speeds. They are tough and suitable for interrupted cutting and are used to manufacture tools of complex shape such as drills, reamers, taps, dies and gear cutters. Tools may also be coated to improve wear resistance.

A non-ferrous alloy of chromium and cobalt, so hard that it cannot be forged or machined except by grinding, it is usually used in the form of a tipped tool.

Also known as cemented carbides or sintered carbides .Have high hardness over a wide range of temperatures and high thermal conductivity. Can be shaped only by special grinding wheels and is always used in the form of a tipped tool.

The hardest known substance is diamond. It is most suited for light uninterrupted finishing cuts at almost any speed and is mainly used for very high speed machining of aluminum - silicon alloys, composites and other non - metallic materials.

Solid ToolsMade throughout in one material. Normally

HSS or carbon

Tools made by brazing or welding a piece of HSS to a high tensile steel shank.

Have a tip of cemented carbide, etc, brazed to a blank of high tensile steel.

Tool bits are held in holders at an angle of about 15°

Cutting Tools Can be High Speed

Steel held in tool holders

Can be also Ceramic (Tungsten carbide) bits held directly in toolpost

Clearance angle Ensures only the cutting edge of the tool

touches the work Too much clearance causes chatter

Rake Angle Allows the chip being

cut to flow out Changing the rake

changes the power used in cutting and the heat generated

Large rake = soft ductile materials

Small rake = hard brittle materials