Jessica,
I have the same issue using 1/4-20, and can't go any faster than 10-12 in/min.
See these videos and read the original thread they were posted.
I haven't implemented this change yet but I'm working on it.
"
http://www.cnczone.com/forums/showth...t=32284&page=4
20 ipm the resonance was bad. No MACH 3 settings were ever changed!
[ame="http://www.youtube.com/watch?v=9RoOZs9LrYo"]YouTube - 20 inches per minute resonce in stepper[/ame]
50 IPM missed steps
[ame="http://www.youtube.com/watch?v=ivDQTeGuduk"]YouTube - 50 ipm test[/ame]
65 IPM motor gets really unhappy in this one!!!!!!
[ame="http://www.youtube.com/watch?v=8Am69_F93yA"]YouTube - 65 ipm[/ame]
"
regards,
Lucian
Insanity: doing the same thing over and over again and expecting different results.
Albert Einstein, (1879 - 1955)