I attached the specs on the stepper motors. I have size 34 P/N PF4913A-05 on all three axis.
Steve...
Looking at that there are two 1280 oz/in motors. Looks like you have been wise and bought the lower inductance one. Although they dont mention it at all. But my guess is the lower current version 34 P/N PF4913A-11 is the higher inductance versoin.
It may be that you are just not driving them with enough voltage. I know nothing of the drives you are using..
I personally wouldnt of had the 2:1 reduction with steppers. It generally makes matters worse, and they need to spin faster with it.
I'm currently retrofitting a small vertical machining centre and have 920oz/in steppers driving 5mm pitch ballscrews 1:1 through compliant couplings. I get over 5000mm/min rapids with no stalling. I'm using 72v supply through Parker drives. Motors rated at 4.2A.
The same motors struggled to spin at an equivilent of 3000mm/min on the bench.
Anyway you can try it without the reduction?
I really dont think this is a signal jitter problem..
Wayne...