# Loosing Z axis again

**URL:** <https://forum.avidcnc.com/t/loosing-z-axis-again/6045>\
**Category:** General Chat\
**Created:** [April 21, 2026, 5:48pm UTC](https://forum.avidcnc.com/t/loosing-z-axis-again/6045 "2026-04-21T17:48:43Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![R-Carpenter](https://avatars.discourse-cdn.com/v4/letter/r/f6c823/32.png) [@R-Carpenter](https://forum.avidcnc.com/u/R-Carpenter)\
**Post date:** [April 21, 2026, 5:48pm UTC](https://forum.avidcnc.com/t/loosing-z-axis-again/6045/1 "2026-04-21T17:48:43Z")

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Running parallel finishing. After an hour or so, Z is lost. First the cutter dropped about a quarter but wet a 1/16" up with each pass.

Running Mach4. Older controll system.

250ipm.

 ![20260421_133418](https://canada1.discourse-cdn.com/flex027/uploads/avidcnc/original/2X/1/18c497402e75acfbcb40f4ea36a4516e1ffa41b0.jpeg)

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**Author:** ![Eric](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.avidcnc.com/eric/32/3220_2.png) [@Eric](https://forum.avidcnc.com/u/Eric)\
**Post date:** [April 21, 2026, 7:15pm UTC](https://forum.avidcnc.com/t/loosing-z-axis-again/6045/2 "2026-04-21T19:15:30Z")

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Have you checked through this: [Z Axis - Troubleshooting](https://www.avidcnc.com/support/troubleshooting/mach4ControlsProCnc/zAxis/)

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**Author:** ![R-Carpenter](https://avatars.discourse-cdn.com/v4/letter/r/f6c823/32.png) [@R-Carpenter](https://forum.avidcnc.com/u/R-Carpenter)\
**Post date:** [April 22, 2026, 1:37am UTC](https://forum.avidcnc.com/t/loosing-z-axis-again/6045/3 "2026-04-22T01:37:34Z")

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I have.

I think it’s the motor. It is making banging noise after 30 min into operation. I pulled the motor off to inspect the connection to backlash nut and it’s fine. No creases on the motor shaft. Run the file again and 30 min in I heard bang from Z axis and the height dropped about 1/8"

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**Author:** ![JeffsDesign](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.avidcnc.com/jeffsdesign/32/5574_2.png) [@JeffsDesign](https://forum.avidcnc.com/u/JeffsDesign)\
**Post date:** [April 22, 2026, 12:13pm UTC](https://forum.avidcnc.com/t/loosing-z-axis-again/6045/4 "2026-04-22T12:13:15Z")

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This sounds similar to what happened to my machine it would randomly drop until finally it completely failed One of the set screws inside the Z came loose I put blue lactite on it and never had a problem since

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**Author:** ![R-Carpenter](https://avatars.discourse-cdn.com/v4/letter/r/f6c823/32.png) [@R-Carpenter](https://forum.avidcnc.com/u/R-Carpenter)\
**Post date:** [April 22, 2026, 1:33pm UTC](https://forum.avidcnc.com/t/loosing-z-axis-again/6045/5 "2026-04-22T13:33:41Z")

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Which set screw? Was it on the motor side?

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**Author:** ![JeffsDesign](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.avidcnc.com/jeffsdesign/32/5574_2.png) [@JeffsDesign](https://forum.avidcnc.com/u/JeffsDesign)\
**Post date:** [April 22, 2026, 2:45pm UTC](https://forum.avidcnc.com/t/loosing-z-axis-again/6045/6 "2026-04-22T14:45:37Z")

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![20230714_214844](https://canada1.discourse-cdn.com/flex027/uploads/avidcnc/original/2X/2/22d9631158e1384006e12c4b0a9f1d41e3641fa8.jpeg)On mine it was this one