XL X axis extrusion v-wheel "guide" is not as "sharp" as my old, stock SO3 extrusion

CNC Machines Shapeoko
1

First of all, I’m not an engineer so sorry for the non-technical description.

On to the problem. I just upgraded to XL. Prior to the upgrade my machine cut perfectly straight lines in any direction. Now, not so much. Any cuts directly along the x-axis are wavy. I’ve discovered in the forums that this may be caused by mis-adjusted, worn, defective v-wheels. Hmmmmm, a mystery to me why moving to a new extrusion would suddenly cause the wheels to wear out but, okay, C3D has kindly offered to send me some new ones. Great!

Meanwhile, while I wait for the new wheels I’ve swapped a few v-wheels around to no effect, still have the same problem. Today, while continuing to noodle the issue I looked closely at the new x-axis extrusion and noticed the rail the wheels ride on has a much rounder apex then the old one. The two, original y-axis rails also have nice, sharp apex. My question is…Is this significant, possibly the cause of my problem. Any other upgraders out there notice their extrusion having rounded rail guides?

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Mine aren’t super sharp. What is important is that the sides of the “V” in the wheel are in consistent contact with the sides of the peak on the rail. The actual point at the top of the rail is pretty irrelevant. Are the wheel eccentrics tight enough so nothing rattles? When running the X rail back and forth by hand, shake it left and right, if there is anything loose, it should be something you can feel.

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3

Sounds like you need to tighten your wheels after the upgrade.

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Thanks Mike. Yep wheels are tight, eccentric nuts adjusted, no looseness or rattles. All appear to be turning consistently, I painted a small white line on each so I could observe them closely. My machine shouldwork fine, that’s why I posted this kinda silly question. Ah well, hopefully the new wheels will let me get back to work.

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Ok, have exceeded my abilities, maybe @WillAdams can kick something in. Both the steppers are plugged in and working, right? Beyond that, I’ve got no idea.

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The only silly question is the one which goes unasked.

First off the apex rounding is a change to make the extrusion easier to make (and maybe less vulnerable to damage) — the V-wheels should run the same on either sort (they have a marked notch in them to account for the apex and to prevent its being present or absent from affecting how the wheels roll).

I’m mystified as well — mechanically the machines ought to be simple, it’s just the intricate inter-relatedness of all the motion which makes things complex. Things to check:

  • pulley set screws — on the Y-axis esp.
  • check all the belt teeth for any bad ones (I find this easiest to do using a dental mirror)
  • Please try removing the V-wheels and check and see if the precision spacer / shim in-between the bearings is properly located and matches in thickness the inner race on the matching V-wheel
  • check the bolt tightness on the Z-axis spindle plate — all the wheels, and also the spindle mount and Z-axis extrusion

Try rolling the machine along and pushing / pulling on the router from the tip of the collet nut — you should be able to see / feel where the machine is moving / improperly giving way.

If none of that helps and the new V-wheels don’t help, contact support@carbide3d.com and we’ll help you puzzle this out.

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Check for cracked wheels also.

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OK Will, I’ll run through your list, hopefully this evening.

Thanks all for contributing, gotta love this forum.

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OK Will, I have completed all the tasks you suggested. Unfortunately the waves continue.

Just as I wrapped up my last test cut and was seriously considering re-installing the old X extrusion the UPS guy arrived with the wheels I ordered from OpenBuilds! Hot damn!

I removed the four “X” wheels (for the 5th time?) removed the bearings and spacers and reassembled them in the new OpenSource wheels.

And, drumroll, a huge improvement! Waves are gone in my plywood test cut. I need to do a circle/square/diamond to verify but I think my problem is solved!

Thanks again to all!

And, I’ll be damned if I can see anything wrong with the old wheels, have to measure what I can and compare.

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