So starting up again, I got the spindle control from Mach set up last night. All seems to work OK, apart from the RPM readout on Mach reads 0 regardless of the spindle speed. Is that normal? The one setting I was not sure about was mach's "spindle pulley" settings. The IP-M manual was not much help on that front. Does anyone know what this should be set to for a 2.2KW chinese water-cooled spindle?

Quote Originally Posted by JAZZCNC View Post
That's most likely to be alignment issue not sticky seals. To be honest I've fitted 100's ballscrews and never had sticky seal on the ballnut(presume you mean ballnut seal)

Now what can happen is often the spacers on the BK bearings are not long enough and the seal in BK bearing can rub on the screw.
This tends to happen mostly on cheap BK bearings. Also on cheap BK bearings, like what Chai Sells, the bearings are not always shimmed correctly or even in wrong way round so when tightening the nut they will bind.

Joe If BK's came from Fred at BST then you can tighten them fully and they won't bind. Fred BK bearings are light years better than Chai's.
Sadly I think I am going to have to strip down the machine and sort out the bearings as they are binding quite regularly and causing pretty major accuracy issues. You get what you pay for I guess, and I should have shimmed them before I assembled the machine - lesson learned!