Part Datum

The part datum is usually set as the center-face of the finished part, as shown in Figure 8.9 below.

Figure 8.9: Part Datum

Lathe tools have two tool offsets: Z and X, which is the distance from the imaginary tool tip at home position to the part datum. There are two ways to set lathe tool offsets. The first involves making a small cut (try cut) on the OD and face of the stock material. The diameter is measured and entered in the control for the X-axis offset. Subsequent tool offsets are found in reference to these faces.

Many lathes now include a tool probe as standard or optional equipment. Please refer to your machine documentation for specific instructions about your machine and its options.

Figure 8.10: Tool Offsets