See: Lead/Pitch Definition The function G33 can be used to machine threads with constant lead of the following type: If an appropriate tool is used, tapping with compensating chuck is possible. The drilling depth is specified by specifying one of the axes X, Y or Z; the thread pitch is specified via the relevant I, J or K. Right-hand or left-hand thread is set with the rotation direction of the spindle (M3 right (CW), M4 left (CCW) - see Section "Spindle movements (Page 63)"). To do this, the rotation value must be programmed under address S or a rotation speed must be set. Note A complete cycle of tapping with compensating chuck is provided by the standard cycle CYCLE840. See the following illustration for tapping using G33: Programming example ; metric thread 5, ; pitch as per table: 0.8 mm/rev., hole already premachined N10 G54 G0 G90 X10 Y10 Z5 S600 M3 ; Approach starting point, clockwise spindle rotation N20 G33 Z-25 K0.8 ; Tapping, end point -25 mm N40 Z5 K0.8 M4 ; Retraction, counter-clockwise spindle rotation N50 G0 X30 Y30 Z20 N60 M30 Axis velocity With G33 threads, the velocity of the axis for the thread lengths is determined on the basis of the spindle speed and the thread pitch. The feedrate F is not relevant. It is, however, stored. However, the maximum axis velocity (rapid traverse) defined in the machine data can not be exceeded. This will result in an alarm.