CIRCLES ARE OVALS - Help!

Hello all,

I have a Shapeoko 4XXL and pocket out circles on a daily basis. This evening when I was setting up my machine to complete an order, something (extension cord) was in the way of the Y Axis and as my machine was going to a rapid position of “S” from the home position, it smashed into the extension cord. I ran over there as quickly as I could to stop the machine from making the terrible grinding noise but by the time I got to the machine, the damage had been done.

I rehomed the machine and upon doing so, it kept smacking into the metal walls at the back corners of the machine.

After playing around for a few mins with the machine, it seemed to be fine and I ran my cut. Upon doing so, all of my holes are more Oval shaped (See picture). I have absolutely no idea what to do to fix this problem as I am not super savvy when it comes to fixing the machine. If you could please help me that would be greatly appreciated.

Thank you

Hi @vees19,

First and foremost, make sure to contact support@carbide3d.com about this.
Now, this could be a number of things, but you should be able to check a few possible causes:

  • it could be a loose of damaged belt. Inspect your X belt and Y belts ?
  • it could be a loose or damaged v-wheel (from the earlier crash). Go back and inspect every single v-wheel, for flats, cracks, or spinning loose.
    • also related to the v-wheels: with the machine turned on (but router off and unplugged), if you grab the tip of the router and wiggle it around (front/back, left/right), can you feel any significant play ?
  • it could be a semi-loose pulley on one of the stepper motors. Use a marker to draw a line across the pulley and motor shaft, run your job, come back and check if everything is still aligned or if the pulley slipped with respect to the shaft

  • it could be that the machine got thrown out of square: with the machine turned off, manually moving the gantry very slowly to the front and to the back, do the left and right sides contact the front/back plates at around the same time ? Is there a significant gap on one side upon contact ?

My guess would be something to do with the v-wheels, but we’ll see.

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Thanks for the detailed reply on this.

I will ensure to contact carbide!

  • I inspected the X and Y belts. All appear to be snug and not damaged.
  • I did notice that after completing my job (after the this all happened), the right Y axis rear V Wheel had fallen off. When I tried to put it back onto the machine, it screwed back in well however as I slowly moved the Y axis forward and backward, I could closely see that the same V wheel that had fallen off, was not grabbing the rail, thus not turning/rotating. All of the other three (2 left and 1 right) v wheels were grabbing the rail and rotating however that rear right v wheel was not.

I tried to play around with it by loosening and tightening it with an Allen key but the only time that it would grab was when the Allen key screw had pretty much fallen out of the baring.

As of right now, I have that v wheel fully tightened but as previously said, it is not grabbing the rail.

  • Router shake appears good, no wiggle either direction.

  • I did that test and after running a order, everything was still aligned.

So I am guessing that the V wheel is broken maybe??? Or worn out or something ???

Thanks again for your help !

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Ok, it’s definitely the v-wheel then.
I’m sure support will get you a new one pronto, but in the meantime, just to double-check: what specific procedure are you using to tighten that vwheel against the rail ? You should unfasten the hex screw just enough that you can then use a spanner to rotate the eccentric nut on the other side, to move the wheel up and down until it contacts the rail (but just barely), then re-fasten the hex screw to lock everything in place. Like so:

(its a SO3 video but I’ll assume it applies to SO4, I may be wrong)

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Even newer machines need the maintenance kit on hand.

So now your scaring me because none of my V wheels have essenteic nuts on the other side…lol. The hex screw seems to just auto tighten when it’s threaded through the other side???

Your two bottom V-wheels on each plate do have nuts. The top ones do not.

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What Kyle said.

@Vees19, this is the relevant part of the SO4 assembly instructions:

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