Issue Cutting Cicles - Solved - X-axis bearing adjustment


My machine has never been able to cut circles very well. It’s about 4 months old now and I need to get this ironed out. I saw on some other posts about tightening the Coupler screws and the screw at the end of the threaded rod. I’ve done all that, they were all already tight, and still the issue persists. Any other ideas?


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Something is causing the motors to lose steps. Run the program again and watch for the lead screws slipping. Probably still motor couplers.

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Ok. I’m not totally sure I have the right idea. But when I did was cut a sliver of tape and put it on the threaded rod as it aligned to the gap on the coupler. I did it for all 3 motor/coupler joints. Then I ran the program and watched, and then checked all the alignments after the program finished. All were in the exact correct place. I assume if there was an issue, the placement would be different, is that correct?

Do the same check, but look at the joint between the couplers and the motor shafts. My guess is that its still slipping at one or more of those interfaces.


Try to put a strip of tape on the motor shafts as well, in line with the ones on the lead screw then run your program again. if after the program finishes and the lines aren’t aligned still, then its slipping.

I tried to get some tape in there, and then a sharpie, neither fit in the tight space. I ended up used my scribe, but I did not see any evidence of shaft slippage. I was hoping to see some… then I would have an answer, but most of my issues, in all things I do, are not the normal issues.
Thanks for the help!

Any other ideas?

If you look at end of the motor there is a hole where you can see the endface of the rotor. Try putting a sharpie mark on there that is inline with the tape you have on the screw.

The pictures you sent are absolutely TEXTBOOK for a loose coupler so thats why many are chiming in to check for that.

Are you able to upload a video showing this motion with the plasma torch off?

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your pictures only capture the possibility of the screws slipping on the shafts…you are not capturing the motor shafts slipping in the coupler

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I have a question! Have you checked for binding on the rails? This could cause a lag on the motor or motors slowing it down but not stopping it. Do you hear any kind of motor chatter when it is moving? You can pull the motors off and mark the shaft then put the coupler back on with the mark inline with the split and then line the coupler up with the tape.

Are the flat spots on the washer roughly a 1/2" long?

OK. Thank you for all the replies. I am going to try and address everything from my testing this morning.
I lined all my tape marks to be at the up most position. Then I used a fine tip sharpie to mark straight up on the rear side of the motor on the shaft. I did this for all 3 motors. Ran the the circle program a few times, checking after each time and all the marks corresponded to the tape.20210309_082736 . I also took 2 videos of the program running for all the experts to see. I hope I captured what is import, if not I can get more. I’ll post links to those in a second since I can’t upload here.
@Burgs04 I attached some pics of the circle, and yes, both the smaller (inside) and bigger (outside) circles have a flat (ish) spot that is about 1/2" on each side.20210309_085929 20210309_085942

I appreciate everyone’s help. I hope we are able to work through this.
Thank you,

Here are the links to the videos. There is some clanging sounds, maybe that’s the issue?

You have a loose set screw in one of the couplings.

The motor shaft or lead screw is rotating one full turn and catching the set screw again. Then when the program runs the other way it’s rotating one full turn. One rotation of the motor/leadscrew is 1/2" of travel distance.

Judging by the way you are taking the pictures it would be your x axis motor/leadscrew coupling. As long as the this is how the axis line up.


Going to say it’s the motor shaft set screw on the x axis.


Both videos are private

Sorry about the vids, it should be fixed now.
I’ll go cut another circle and see which axis seems to be the issue.

OK. It looks like the flat spot runs parallel with the Y axis. Just like what you said in your diagram. When you say the motor shaft set screw, is that the screw on the coupler closest to the motor? If so, that screw is super tight.

20210309_093604 20210309_093612

Do you have a busted bearing? That sounds terrible. Whatever is clanging is the problem. It does it in rhythm. Find whatever is making the noise and mess with it until it stops making noise.


I’ll go check. It’s made that noise since day 1, so I assumed these tables just made a little racket. :slight_smile: And for a few weeks, I never really cut anything that wasn’t a line of sorts, so there was no issues with cuts for me to have reason (other than I’m obviously very new and ignorant to all this) to think that machines didn’t just make noise.

Once again, thank you all for the help.

Nope, not normal at all. Loose motor couplers wouldn’t make a noise, or would sound high pitched it one binds but the other spins.

Does it do it when you jog the x axis?

I noticed this when trying to track down the noise. I can move the whole Z (i think) axis assembly some with my hand. See video. Should that be a more solid connection?