Siemens SINUMERIK 808D Milling Programming And Operating Manual page 34

Setting-up
3.1 Setting up tools
Figure 3-1
Operating sequence
...
34
Determination of the length offset using the example of a drill 1/Z axis length (milling)
1. Select the desired operating area.
2. Switch to "JOG" mode.
Open the lower-level menu for tool measurement.
3. Open the manual tool measurement window.
4. Use the axis traversing keys to move the tool to approach the
workpiece in the Z direction.
5. Switch to "HANDWHEEL" mode.
Programming and Operating Manual, 12/2012, 6FC5398-4DP10-0BA0
Milling Part 1: Operation