Im using the 400 ozin motors and Probostep drives from probotix. Im trying to turn a 1/2-10 lead screw with a 4:1(ish) gear ratio. a 42 tooth pulley at the motor 11 tooth at the screw. The screw turns prertty freely but it seems no matter what speed/ step combo I try it stalls out. if you want to see the machine its on my build thread is here
http://www.cnczone.com/forums/diy-cn...tml#post857828
ideas? Id hate to think that a 400ozin motor really couldnt turn this screw but I guess its possible.