Hello all, I have a Tree J425 with a Delta 40M control. These controls are a little unique with cutter compensation. Most controls in my experience "ramp" into cutter compensation, but the Delta 40 moves directly into the diameter offset - instead of a transition move that starts without comp and ends with comp, the cutter offset occurs at the beginning of the transition move 90° to the cutter path, and to the left/right depending on selection.

Anyhow, on to my question with regards to internal thread milling (or any internal circular milling operation) using cutter comp. I find that I must start above the hole in order to make the transition to cutter comp without crashing, then I can spiral into the hole to cut the threads. Fortunately the cancel cutter comp move at the bottom of the hole behaves properly when I command a move to the hole center and cancel compensation. Then I can safely retract.

I've been trying to find a move that makes it possible to start at the bottom of the hole on center, then activate compensation and spiral up and out of the hole. Why? Excellent question, probably because I can't find a solution to the problem. I can't think of any practical situation where this would be the only option. Does anyone have experience entering compensation inside a circular hole or pocket, where the clearance is less than the cutter diameter? Please let me know if you have a proposed solution to try. I've tried tangent radius entry and direct entry, and given the way the Delta control makes it's entry move it will crash the cutter into the part. TIA.

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