with a load they are skipping or loosing position
That's what i meant by headroom.....
Go back and look at all the stuff about steppers on the Gecko site for understanding stepper basics
as it's beyond what I can comment on here.
Probably at the velocity you don't have much motor torque left so as soon as it sees a load
it starts to skip. Don't know how much your using just to move the axis ( it can be measured ) so if that is minimized you have more power left for machining. Frankly i changed out the motors on my Sherline from
...i think they were something like 160 in oz ...to 500 in oz and have plenty of power and velocity.
I use 500 in oz on the Atlas mill and can do 100 IPM and break end mills. The motors are only using 3 amps
and the inductance is low and only using 36 volts.
Supply voltage, amp setting, gearing used, how wired can all make a difference in the motor / axis preformance. And understand that there are trade offs. Increase voltage and velocity will increase. As motor rpm increases torque decreases. More amps more torque ....but none of these are single change and single performance improvements. Manufactures provide motor curves based on different voltages providing a torque to rpm / steps' rev plot.
Go to the gecko site and you will find some formulas to calculate and you will find that Gecko say's you want power = speed x torque!
So what i am basicly saying is that the "whole" thing is a SYSTEM and the system needs to be designed to meet YOUR needs.
Sorry, but this stuff is not just plug and play....but....having a look at what a lot of vendors provide and users use is still a good base to kick off from.
BTW, I think in the Members Docs i posted some basic design stuff for the 6" Atlas Lathe Conversion
thread.
RICH