Z Axis Motor Grinding on lift

LowRider CNC Troubleshooting
1

Hey guys :wave:

I’m so close to actually cutting I can taste it!

I’m having an issue on my new build lowrider3 Dual Endstop whereby when the Z Axis is homing the motor is grinding on the way up.

This has only started happening once I have added the router (ie weight). With it squaring nicely with just the pen.

I have done a short video to show the issue (with extremely low production value :joy:)

Things I have tried:

  • Swapping Z Motor connections to the board to different sides (testing if the wiring crimp I did was crap)
  • retightening the rails (they were a little loose so was hoping that was it!)
  • reconnecting the x rail to the sides and checking tightness of everything (I think) that are related to the machine moving up and down.
  • moving the X to the opposite side and homing (works fine - most of the time).

My next step was to reprint some parts to see if they printed out of wack or something

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2

That’s not right. I put a huge vise on mine and it lifted it fine. So the router shouldn’t be a problem.

The fact that the leadscrew is tight and not falling tells me that’s where the problem is:

  1. Did you lubricate that leadscrew/nut? The steel on brass needs lubrication. I use some thickish stuff from my bike. I think Ryan includes a tiny packet of lube.

  2. The nut needs to be perfectly aligned with the screw. The brass nut can get a little out of whack if it is totally tightened with 4 screws. So try loosening those, or leaving only 1 installed.

  3. Check that you have a 4 start leadscrew. You can look at the top and see how many threads start at the end. It should be 4 and not 1. If you have a 1-start, then we have to reduce the top speed.

When you have all of that fixed, the gantry should drop on its own when you disable motors. So that is a good sign you have something wrong or at least non standard.

And thanks for the video. That was helpful.

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Firstly - thanks for the insanely fast response!

I haven’t lubricated! That would be it for sure then I would say. Having it drop when it is turned off has never happened to me, so that will be a nice feeling if that happens.

Will let you know.

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4

Hey again,

That well and truly solved the issue! Thanks!

  1. The lubrication of the leadscrew was the missing piece which just made for a beautiful SILENT move up and down. I dont believe there was anything else to lubricate?

2/3. The nut was the correct one, however I did have 2 screws in and decided to go one which also helped the alignment more rather than having it forced ever so slightly out.

I went through and did a test move/cut for the Strut (without the router going) and it all moved beauifully smoothly which was so satisfying! I have cleaned up the table and acables now, ready for the first strut cuts when I have a few hours spare.

Cant wait to get cutting!

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