So for G76 to work I have to have some way of sending a signal to Mach3 telling it how fast the spindle is turning, is that correct?  I thought that if I programed in the spindle speed, and then set my VFD to get that speed I would be good to go.  Right now I have a MachTach tachometer installed which gives me spindle speed but I am not sure if I can feed this info to Mach3.  If I am on the right track here what is a good simple way of getting RPM into Mach3? Thanks.

You will need an index as an input to Mach3. Mach will read the index and the display the true rpm of the spindle.
The index is also used in thread timing as it needs know when to start the thread cycle passes.

I use a Halls Affect sensor as it is easy to install in tight places.

Have a look in the Mach 3 Using Mach3 Turn manual for additional info.

RICH

 

Thanks.  Do I still need index input if I use G32 for the long form threading approach?

Yes

RICH