Lathe ToolBits

·A lathe toolbit is shown in the figure below, with a few terms defined.

· In general, as the rake angle increases (positive), the cutting forces are reduced, the surface finish improves, and tool life increases.

· The side edge cutting angle has two effects outlined below,

· The End Relief Angle prevents friction on the flank of the tool. The holder for the bit is often angled, and the end relief angle must be larger than the tool holder angle to prevent rubbing.

· The side relief angle has a function similar to the end relief, This angle must exceed the feed helix angle.

· Increasing the nose radius improves the surface finish. But this reaches a limit.

8.2 OPERATIONS ON A LATHE

· Operations on a lathe include,