Shapeoko Pro Squaring Issue

Hi guys,

I have had my pro a couple of months and it’s been doing its job OK. I never managed to get the x gantry to square properly with the endplates but I wanted to get cutting so ignored it. I thought I’d try again to get the machine properly squared so I’ve disassembled it and armed with two months of CNC knowledge I’ve tried again.

It’s un-squarable.

I’ve stripped the machine back to the four aluminium crossmembers and removed the belts. I have also removed the black support panels which, frankly, seemed incredibly tight between the front and rear endplates. I removed all the screws holding the y rails to the aluminium crossmembers and re-snugged and backed them out. I have also tried loosening the x gantry bolts to get a bit more flexibility.

I get the gantry square, tighten the bolts as per the instructions and a gap of between 0.004 inches (0.1mm) and 0.014 inches (0.35mm) appears between the left front y rail and the right rear y rail. If I pull the gantry forward to close the gap and then let go, it springs back to reveal the gap again.

The instructions say that there should be no gap and looking at the way it’s built, I can believe it should be pretty much self-squaring.

I’ve tried pulling opposite corners together using rope as per a forum post. Tighten the bolts and let the rope go and it’s unsquared again. Can anybody provide any advice while I wait for a response from the support team?

Please contact us about this at and we’ll do our best to work this out with you.

Already done :slight_smile:

Hopefully I’ll get it sorted and reassembled soon. I was intending on entering a forum contest one of these days.

To be fully technical, the machine is likely square along the axis. It hitting the end plates at the same time is not a requirement for squareness.

That’s interesting. The assembly pdf, section 4.5 “Square the Machine” is what refers to this endplate procedure.

Is the gap not significant?

That’s a lot less than I have. I have an SO3 XL (pre in-house extrusion squaring). I’d say wait to hear back from support and see what they say, but I wouldn’t think that’s a show stopper.

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It is nice if they’re exact… but the linear rails being parallel to each other is the important part. And that happens automatically with the X gantry, the linear rails, and bearing blocks setting that distance. :slight_smile:

I built aerospace parts and 0.014" in an assembly that has tens of parts is pretty good. The extrusions are likely built with a length tolerance. 0.010" is within 95% of the parts I built. You have two different extrusions machined at that tolerance and the possibility of 0.020" is within tolerance if one is on the low end and the other the high end.

My Pro is off that much too, but it doesn’t effect how square it cuts.

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I fired off an email to support as well. The front plates have a 0.8mm difference so I want to see if I need to do anything.

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You might take and fix a square lined up with one of the t-tracks and clamp it down, then with the router off, install an end mill and jog it down to the front edge of the square and jog across the x and y axis to check for squareness.
(of course, leave yourself a bit of a gap between the square and bit so you don’t scratch or damage anything).

Thank you everybody for the replies. I’m feeling like it’s maybe not that serious. I suppose I thought this had something to do with my X and Y travel being off by 0.11 inches (3mm) over 27.5 inches (700mm) of travel.

While I’m here, does that sound like a normal adjustment? Seemed like a lot when I know several machines have been perfect straight fom Carbide 3D.

Once you get a response from support if you could share their recommendation/comments that would be great. Your definitely not alone and for closure a do this to fix it or do not worry about it would be good.

As @SLCJedi noted, it’s a tolerance thing which I believe is poorly written about in our instructions.

We’ve seen the ticket, and have escalated it to the folks who have experience w/ Pros and will have an official statement (and likely update to the instructions) presently.

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Thanks Will. The instructions are actually pretty clear though - “There should be NO GAPS on either side.” - the full caps is part of the instructions, I did not add it.

No gaps = tolerance of 0, right?

There was actually a change to the docs to eliminate that “No gaps” statement because it’s wrong. There’s nothing in the design of the machine to accurately locate the end of the Y rails relative to each other because that’s not important. The only thing that matters is that the Y rails are (relatively) close to parallel to each other.

I confirmed that the docs got changed, but I’m not sure if they’re uploaded yet ( I’m sitting here alone in the office today so there’s nobody to ask.)


As the person who designed the machine / structure:

The assembly docs are incorrect and are being (or are already) updated to exclude the ‘no gaps’ statement. I believe that was a misconception from our tech writer from the S3 design, where aligning the Y plates to the front/back plates was a good visual representation of if the base was square to the Y axis.

With the Pro (and the S4) this isn’t the case. As Rob noted, the Y rails need to be parallel to each other, but the ends of the Y rails are not important or even relevant to the overall squareness of the machine. If there is a gap at the front or back (on either side) that doesn’t matter.

What actually makes the machine square is the hybrid table. There are qty:80 6.2mm countersunk holes which hold the M6 flathead screws. Countersunk holes are by default ‘self-centering’. By the time your screw down the hybrid table, those 80 countersinks have essentially locked in the frame and averaged themselves out to being as square as the table will ever be.

Also: if a topic regarding squaring a Pro (or S4) ever comes up in the futre, please point them to this post.


Well that’s a relief. Thank you for the update Rob and Edward. It’s great news that my machine is OK and I hope others will find this post useful until the docs are updated.