Siemens sinumerik 840D sl Operating Manual page 543

Figure 13-14 Tap (Type 240)
Figure 13-15 3D probe
Note
A 3D probe must be calibrated before use.
Turning
Operating Manual, 07/2010, 6FC5398-8CP40-0BA0
Machine manufacturer
The tool length is measured to the center of the ball or to the ball
circumference.
Please refer to the machine manufacturer's specifications.
Tool management
13.4 Tool dimensioning
543