The reason you can not change RPM on the same part, is that, the CNC lathe's encoder sends a start signal at the beginning of the thread cycle at a particular RPM. When you change to a different RPM, there is a time delay or mismatch that changes the tool's angular entry point... there is no way I know of to account for or calculate that change. That is why using G96 on a thread is a no-no... you should always use direct RPM, G97. I always set up a new part using a very low RPM so that I don't lose the first part because of chatter on the threads... then, you can increase the spindle speed between each part, until you reach the optimum RPM without chatter.

I was hoping you would say that. Alas, the commute would kill me.

:crybaby: :crybaby: :crybaby: recently finished 500 15-5 nuts @36 Rc. Had some trouble with off center drilling to 1" with .750" insert drill (in another thread). Threading, milling hex, drill tiny holes as mentioned above, machine worked great. Super surface finishes and fine tool life ..once dialed in. still waiting for the check to clear.....

Re: X7 I've searched this and didn't find the answer I wanted. I've got a plate with (800) drilled holes of 5 different diameters, the problem is that I have (400) 1/4" holes with 3 different depths. Mask on arc would be great for selecting the 1/4" holes but how do I filter out the different depths? The depth filter option under sorting doesn't seem to help. Is there an easy way to accomplish this?

Sounds like the GUI is missed up. You can try this. Close Mastercam Run regedit.exe delete HKEY_CURRENT_USER\Software\CNC Software, Inc.\Mastercam X8\GUI Ernie