Sensor less vector vs closed loop vector

[Clive S]

is it quick enough to pick up the change in spindle speed as cut starts? Im looking at as high a speed and max depth of cut as possible.

Well I am not an expert but if your spindle has enough torque it should not slow down under normal threading use. EMC (LinuxCnc) is very fast and can handle fast encoders I take it you will use a mesa 5i25 with a 7i76 or similar I also have put to jog wheels on to use the lathe in manual mode. Perhaps you should ask your question over on the linuxcnc forum for the correct cards especially if you want a tool changer as well. I will follow your conversion with interest

[Ross77]

Thanks Clive.
I finally have a bit more time and a purpose to get my CNC projects finished. Yes I will probably end up with the mesa cards, it depends if I can get the Kollmorgen servo drives to work and what I need to interface to them. Build should start in a month once I have a clear idea of what to do. biggest problem is the cross slide!

I will ask on the Linux forum and see what the consensus is but from reading around it seem to like you said, as long as the spindle isn't under powered and it is a good quality VFD then the spindle speed should remain constant. 3HP should be ok but I suppose I could do some test cuts in manual mode and monitor the rpm.

Have you got a build log for the Myford ?

[Clive S]

Have you got a build log for the Myford ?

Unfortunately I haven't I just made an encoder disc driven off the spindle (not the motor) 1:1 and used steppers on the X and Z with the original screws (these might be changed). I also got rid of the compound and made a solid block on the cross slide instead. Hence the jog hand wheels for manual use etc.