Siemens SINUMERIK 840DE Programming Manual page 179

Example of chamfer, CHF/CHR
For the chamfer insert another linear part, the chamfer, between the linear and the circle
contours in any combination. The following two options are available:
N30 G1 X... Z... F... CHR=2
N40 G1 X... Z...
or
N30 G1 X... Z... F... CHF=2(cos α ·2)
N40 G1 X... Z...
The chamfer is inserted after the block, in which it is programmed. The chamfer is always in
the plane activated with G17 to G19.
Fundamentals
Programming Manual, 10.2004 Edition, 6FC5 298-7AB00-0BP1
4.22 Chamfer, rounding (CHF, CHR, RND, RNDM, FRC, FRCM)
Programming Motion Commands
4-73