Initial chucking is a concept in Swiss that does not exist in Turn/Mill. This is carried out at the start of the program and refers to the process of setting the amount of exposed stock in front of the main chuck. A typical initial chucking sequence for a Tsugami machine is shown below:
G300 [<Y-CHANGE>:<SW-WORKING-LEN>+<CUTOFF-TL-WID>+<CUTOFF-TL-OFFSET>+<SW-FACE-ALLOW>+<SW-Z-SAFETY>]<EOB>
G150 [<Y-CHANGE>:<CUTOFF-TL-OFFSET> - <SW-FACE-ALLOW>]<EOB>
The first line positions the chuck by specifying the complete exposed length of the stock. The second line sets the location of Z0 once the chuck is in position. Typically, at this point the stock will be in bar-stop position against the cutoff tool, and its face will not be located at Z0, so the G150 value is nonzero. <Y-CHANGE> is used above to ensure that the calculated value has a factor of +1.0.