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Hi Guys,
I bought an uc100 and use on mach3 that is stable.
,but Mach 3 threading is not stable that change pitch (step screw) .For example, I setup g76 1.814mm pitch ,but front of screw is 1.4mm ,the middle is 1.814mm ,the end is 1.4 or 1.2 mm.Diameter is 20.995 mm .(Pipe screw)
How do I solute that problem?

This issue can happen with our Mach3 UC100 plugin, because the threading is syncronised only one time in the beginning of the thread cutting cycle.
This is done this way, because the MAch3 threading cycle is buggy, so it is kind of impossible to implement per turn syncronisation.
You could fix the issue if you could produce a non varying spindle speed.

With the UCCNC thread cutting is done with incremental encoder feedback with precise realtime syncronisation.
Maybe you will want to switch to UCCNC later on as the UCCNC with the new lathe functions will be released soon.

thanks you , but I asked a friends who has been cnc designer for 10 years tell me the ucncn has the pulses lose time,and ten or more teeth after not stable pitch for example 20 pitch then not not same pitch

Your friend is wrong, the UCCNC does not loose steps with time, instead it has a much more advanced motion planner than MAch3.
And UCCNC cuts perfect thread with continously syncronising the pitch to the spindle encoder.
However UCCNC is not yet optimised for lathe usage, but it will be in the next release.

With Mach3 the issue is that the plugin only syncronises to the spindle speed once when it starts cutting the thread, so if the spindle speed fluctates is seen on the pitch.

thanks ,I solved my problem that is accelaration what is so low