The tool length offset represents the distance from the tool tip when the tool is at tool change position and the Z zero position of your part.
If you simple apply the "H" code it will place the tool tip at Z zero of your part. I.E. the tool will touching the part. Instead program something like: N4 H1 Z.1 M8
This will place the tool .100" above the top of your part and over the lap the "pump up" time for your coolant to get flowing before the tool starts cutting.
Neal |