X- axis binds every 3-4 inches, not sure why

Sorry, gang…I know there’s a bunch of these already, and I have read them, but I didn’t see anyone mention this specifically.

I’ve lost X axis tracking, gradually, over the past 4-5 carves. It’s moving left with every subsequent cut, about .1 inches per pass.

When I try to move the spindle left and right along the X axis with the machine off, it moves perfectly for 3-4 inches, then binds. Applying just a touch more pressure pushes it past the jam, and then she’s free again for 3-4 inches, then lather, rinse, repeat. It feels as if a wheel is jamming but they’re all free. I was hoping the slippage was the gear wheel on the stepper shaft coming loose (which I will also check) but in the meantime I found this binding problem.

Do I just take the X axis apart at this point and rebuild the mechanicals? I can’t visualize what’s causing it to bind repeatedly at the same interval, when it’s on a different section of belt at each of those jam points.

Lil help?


I haven’t put a meter to the circuit board but I believe I’ve got the pots set correctly. I’ve adjusted them before when they were too low, on initial setup, and they’ve been fine for months. I don’t hear the thermal overload they guy is getting in that video.

Plus the binding happens with all power off, with the machine not under load (physical or electrical). Thanks for the vid link though.

I’ve done zero modding at this point. I’ve added a suckit boot (big recommend) and that’s it. The gantry and electronics are stock, and I’m running a Dewalt trim router for a spindle.

I can see it skipping or stuttering under a load occasionally, but not usually. I just notice as each subsequent pass happens that it’s off a hair, but only in the X axis. If you carved a square, for instance, the left edge would have steps in it all the way down, a staircase moving down toward the left, whereas the right edge is completely vertical (but obviously, as the cuts are getting jogged to the left, the same thing is happening on the right side of the square and these subsequent passes just end up cutting all the way through the material.) Y axis is solid, and I would see no issues carving the top and bottom of said square.

Thanks for the tip on not moving it by hand. I was moving it by hand to try to determine if the X axis belt drive wheel was slipping on the stepper motor shaft. I wasn’t moving it quickly, so I don’t believe it was resistance building up in the motor, but I could be wrong.

Really…I guess that makes sense. More stuff to read on forums then, I guess. Back to the drawing board!

Thanks Phil.

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Time to read up on stiffening then? Have you upgraded your rails, Phil?

I had something similar happening a couple weeks ago…and turns out I used Loc-tite on everything EXCEPT the set screws in the pulleys on two of my motors. I had to order new ones cause they were no where to be found. but I noticed the same stuttering every couple of inches when the gantry moved left to right…and in my case also on one side of the X. Check to make sure your set screws are in and tight…


Thanks Shane. I’ve got zero loctite on anything at this point. That will change this weekend.

Try unwiring the X-axis stepper motor, loosening the V-wheels all the way, and trying it again by hand. If it binds, you’ve got a mechanical problem. If not, the problem is either stepper-related, or more likely, V-wheels. Might have a chip or something stuck in a V-wheel, or a flat spot forming in it.

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Thanks Robert. Good ideas. If I quit my job, I’d have more time to tinker. :wink:

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If you look at the belt in the pulleys while you move the gantry can you see the belt moving back and forth across the pulley? I’ve noticed a thump when I’m pushing the gantry and the belt hits the side of the pulley.

Ok, progress. Disconnected the stepper motor and still had the binding every 3-4 inches. Disconnected the belt and still had it. Started pulling off bottom wheels and it eventually stopped binding. Cleaned the v wheels and they had some gunk built up in them. Reinstalled them loosely and the binding stopped.

Putting it all back together tonight with the loctite blue. Unless I decide to do some stiffening. I’ve got projects backing up, about 40 orders. Yikes.

Thanks for all the help and advice, and especially for everyone’s attitude on here. Y’all are cool and helpful, where folks on forums tend to be, well, not. :wink:

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Yeah Phil, I bought the Suckit and it’s been great. I did run it for a while without the boot so I probably shot myself in the foot with the crud in the wheels.

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I guess the combination of the crud and maybe a slight shift in the eccentric wheels was binding her up. Thanks for your help.


Back in business. Reset X axis carriage wheels with loctite blue applied. Reset all belt tensions. 1/2 way through a 20 min carve and it’s all tracking good.

Guess I’ll try stiffening once I get this batch of work done. Thanks again, folks. Huge help.

I had the same thing and found my V wheels needed re-adjusting, removed all of them and made sure everything was aligned/tightened properly.

I also found the two bearings on most of the V wheels were not seated correctly, I squeezed each side of the V wheel until I heard the ‘pop’ of the bearings seating in place and it was all fine after that.