Wavy X axis cut

When my 3 XXL is cutting along the X axis (cutting right to left when looking at the front) I get a lot of waviness in the cut. Any suggestions on what to check? I don’t notice any odd noises from the machine.

Wavy X axis cut

Straight Y axis cut

Check the V-wheels on the XZ. They should be snug, but not too tight.

Are you thinking they’re too tight or loose?

The first thing I would check is that they’re not too loose.
If you pull/push on the endmill, is there any play?
Conveniently, @LiamN just wrote about this here.


I’ll add that if the wave has some periodicity to it, you want to check whether your V-wheels are still round. Wearout or chipping/dent in one wheel could cause this too.

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I’ll give all these things a good look today and report back. Thanks!

Alright so I gave a look today and didn’t notice any major slop in the v wheels. I did adjust one to be a little tighter to be closer to the others. I did some more cuts with no change in behavior. Attached is a picture of facing with a 1/4" Amana O flute bit. 14ipm, 0.015 DOC,
50% stepper, face operation. There’s definitely a pattern in the cut so something must be wrong I’m just not sure what to check. Maybe the wheels need to be even tighter? At this point I can turn them with my fingers but it takes some effort.

I totally forgot about your response Julien. Would you think bad v wheels based on those pictures? The machine doesn’t have a ton of hours (probably cless than 50) on it but it did have a pretty bad crash where the bearing on my router seized up.

if you can try to visually inspect them for a crack through the middle; those have happened before on this forum and the result was a periodic distortion (not super common though)

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also neil’s suggestion to see if there’s any “slop” or movement if you try to move the collet in the router (with the machine on but the router off). There should not be any slop even if you try to put some reasonable amount of force on it (up to stepper motor limit which is iirc 17 lbs or something)

I’ve had a dewalt router where after some use (and crashes) the router developed slop… but I’ve also found lose vwheels and some other fun with this

Thanks for the cracked suggestion. I’ll give that a look tomorrow. I grabbed on and pushed on the router and the whole z-axis tilted - no real slop at the wheels, so I think I’m good there.

My criteria is: with the machine powered off, if you try to rotate the v-wheel by sliding one finger under/over it, does the carriage move, or the wheel ? I tighten until it’s the carriage that moves when I do that.

I honestly can’t tell based on the pictures alone, it could be a number of things. Like @fenrus suggested I would inspect every single V-wheel, moving the carriage slowly and checking whether you can detect any crack (either between the two halves of the wheel, or a radial crack), or any bump.

It’s all subjective but you shouldn’t feel any significant slop/tilt at all when trying to tilt the router/Z axis. Which Z axis do you have again ?

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hmm if you have a hdz or z+… the Z axis is not supposed to move.

please also check the vwheels that hold the whole X beam onto the Y axis… I’ve had those be loose, and that gave some really subtle but funky effects

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Ok I cleaned and inspected all v wheels today and made some minor adjustments. Some were maybe a little too tight based on Julien’s suggestion, only found one that was too loose. I didn’t feel any lumps or see any cracks.

I have the Z+ Z axis. If I push on the router I definitely get some movement front to back but it’s the entire Z+ moving not the Z beam itself. Maybe wheels need to be even tighter to eliminate that? Thinking about where I notice it the most is right to left on the bottom of the workpiece, so force would be pushing the cutter away from the beam.

… This makes the Pro look so appealing :rofl:

Side note: I appreciate the help. You all are always so helpful even for people like me that don’t really know the intricacies of these machines.


Yes, you need to adjust the eccentric nuts so that the Delrin V wheels hold things in plane, please see:

You might also want to check on your belt tension.

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So there is no visible play at the vwheels but the Z carriage still moves front/back enough to be noticed ?
If you have a chance, can you capture a short video of that ?

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look for cracks, look for gunk on them, and look for gunk on the rails themselves, top and bottom. Do the same for the Y axis (it can cause rotation around the x axis) - don’t forget to check ALL the wheels.


Sorry for the delay here. I’ve cleaned, checked wheels, got a new bit, and made some slight adjustments to v-wheel tightness. I have two more aluminum mounts to make but haven’t got around to it yet. When I do that’s when the waviness will rear it’s head if it’s still an issue.

Fingers crossed!


OK so getting back to this. After making the adjustments and going through several cuts I now have a very repeating pattern of wheel marks on my X axis. That pattern looks remarkably similar to the pattern I was seeing on the aluminum. I’m guessing that means I have a wonky wheel (or multiple). I’m going to replace the wheels on that axis.

Anyone have any suggestions on where to buy just wheels?