Drive shaft pulley will not turn

Please help! The Z motor pulley works but the ACME drive shaft pulley will not turn. I have loosened the pulley…tightened the pulley…readjusted the Z motor to tighten the belt. When I turn it on and test the Z axis, just the Z motor pulley turns. I don’t know what to adjust anymore!

Are the set screws that hold the pulley to the shaft tightened down?


Did you move the delrin nut up and down the acme rod a few times to break it in? Second question (the stupid one), is the spindle fully up or fully down, and being pushed against the top or bottom?

I did a test carve and it worked great…the spindle is close to the top but not pushing on anything. just noticed I can not get the green light on the gshield when I move the pulley by hand…have checked all the wiring and it is good.

Did you look for any loose wires, or anything that loosened up during the test cut? Is there any chance you pinched the insulation in the connectors and had intermittent metal-to-metal contact, or the wire got pinched or damaged? If you know the wiring is correct, you may want to try to check continuity through each Z-axis stepper wire (with everything turned off and unplugged).

Ok. I will go back through the wiring.

Sorry! Found a loose wire! Thanks for the help.

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At least it was a simple thing.
Those, when we find them give us a sense of accomplishment and boost our confidence making us want to push the envelope with our machines just a little further, enhancing our understanding of this crazy little hobby we have embraced.

How much further is dependent upon the individual. Some more some less.