Cutter radius offset is also known as the tool nose radius offset on CNC lathes. Its purpose and overall functionality is the same as for milling applications and has been described in great detail earlier, in a separate chapter Using Cutter Radius Offset . This section will only cover some additional items important for lathe applications, mainly the effect of not programming cutter radius offset.

Surprisingly, a significant number of machine shops do not use cutter radius offset on CNC lathes at all or using it poorly. Regardless of the reasons (some are mere excuses), the message is simple in manual programming you do need to compensate for the tool nose radius. If you don t, the finished part just will not have the right dimensions it can t have.

The main reason is the method of setting up the tools for turning and boring. In majority of setups, the mounted tool is touched-off the Z0 face to get the Z-axis geometry offset. The same approach is applied to the X-axis as well, but since it is impossible to touch the center line, the measuring process takes some extra steps, but the final result the X-axis geometry offset is the same as if the center line could had been touched. Both measurements are made between the extremities of the tool tip and the X0 or Z0. In practice, it means there is a significant difference between setting the radius offset for milling applications and doing...