@CncJim I’ve also invented a few new words, most have extra letters 
Haven’t had a bit work it’s way up in the collet yet, it seems to go down for some reason. And only when the router is spinning at 18k rpm. Probe worked fine. I got in the habit of taking the nut and collet out and cleaning them both when removing the bit after the project is done. Took care of that problem.
I think if you are using an up-cut bit, it would be pulling itself into the work - possibly a reason it would walk its way lower. A down-cut bit would go the other way. If I had to guess, I would say the axial forces are dominated by the direction of the flutes (but that’s just a hypothesis).
Now I’m sure someone in the thread had an opposite experience - but question for those who have seen the bit move up or down in the collet - were you using an up-cut (pulls chips up, leaves a rough top surface), down-cut (pushes chips down, leaves a clean top surface, but would blow out the bottom) or compression (partially up-cut, partially down-cut) bit? What kind of milling were you doing (boring, clearing, etc.)?
Just thinking out loud…
@elbarsal Ed, I think you may be on to something. I was using a 2 flute upcut EM in a pocket.
Have not had it happen with a v-bit / engraving bit.
@W.g Hey Wally
I checked the dxf file with the Vector Validator in Vectric and found 4 overlaps and one intersection. Also, have you set a flat depth? Trying to eliminate the software part from the equation.
Rick,
Thanks! I actually fixed the overlaps, but did not try a flat depth. Follow up question back to you; I am carving onto a dome shape, would the flat depth affect the lower portion of that shape, or will it adjust?
My shop is in chaos right now, just added a dedicated laser and in my small shop almost every item has to be moved between 8mm and 4 feet. That is my task today. So if you know off the top of your head, great! If not I’ll set up another test piece soon.
Thanks again for helping me with this issue,
Wally g
It will adjust even when projected onto a dome. Flat depth is a built in safety feature for me anyway.
That is a brilliant idea. Going to do this from now on. Thanks for the tip.