Quote Originally Posted by gerrymoore View Post
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For economy reasons, I'm using ordinary threaded rod with ordinary nuts..I know all about backlash but I'm broke!! This means that everything runs a bit slow as it takes approx 17 turns for a 25mm movement.

I have measured it at 'rapid' feed rate to be around 20 inches per minute - not too bad....... but of course when it's 'cutting' (drawing) it's much slower.....also, if I try to speed up the steppers they just seem to stall - don't know why - hope someone can explain......

Is there anything in the Gcode that I can change to speed the cutting up a bit....remember 3 months ago I'd never heard of Gcode!!
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Anything simple I'm doing wrong??
Well done on getting something working...!

OK 17turns for 25mm = 1.5mm pitch threaded rod (M10?)

20ipm = 8.5mm/sec @1.5mm pitch = 5.7revs/sec which assuming 200step motors = 1133steps/sec. which shouldnt max the motor out but depends on drivers. You dont say what controller software but you should be able to increase it there.

The threaded rod/nut combo very high friction so most of your motor torque going into turning the rod not moving the load.

You may find that a brass or Delrin nut will give improvements.

A higher supply voltage (if the drivers can stand it) may give improvement.

What motors, and drivers and power supply voltage?