parameters for lathe tapered thread in OnCyclePoint?

[ubunibme]

I'm modifying a post for a linuxcnc lathe to support the 'D' parameter in linuxcnc G76. (this causes the thread to cut at a tapered angle).  I've modeled a 1/4 NPT taper, and used the dumper post to look at the parameters available to 'OnCyclePoint'. For the life of me I can't see anything that indicates it's cutting a taper, let alone a 1.788 degree taper. Where would this info be found?

[ubunibme · Accepted solution]

OK, I found the answer, it's the 'cycle.incrementalX' parameter. This will be zero on a straight thread, but the correct offset from the beginning of the thread pass to the end. Atan(cycle.incrementalX / cycle.incrementalZ) gives the correct angle of thread.