Help! 3XL base is square but carriage is not!

[DPME (David)]

My S3 XL seems to have developed an out of square issue. The base IS square corner to corner, close enough that I can’t tell the difference and the machine hasn’t moved since it was built.

However, sometime over the last few months it’s developed an issue where the carriage is not suqare to the machine. When the left side of the carriage is all the way to the front (carriage side plate touching the front plate), the right side is still about 4mm away. The result is that the things I am cutting are no longer square (they used to be).

Over a short distance it’s not really a problem, but over the full width of the machine pieces could be 3mm - 4mm out, as I found out when I made something this week that I had made a couple of years ago and they don’t match.

I’ve looked at the V-Wheels and all look fine. What else could be causing this and how can I fix it?

[WillAdams (William Adams (Carbide 3D))]

Remove all the belts and check them, inspect the V-wheels as well.

If all is okay:

Loosen all the hardware and push down on everything and check w/ a square and verify that things are equal corner-to-corner as you tighten things backup.

You should be able to pretty much rebuild a machine to like new using the Maintenance Kit:

Shapeoko Maintenance Kit

and you may want to level, and if need be, replace your MDF baseplate:

Support Files and Utilities

Let us know what you find out at support@carbide3d.com and if need be, we have more detailed leveling instructions.

[ScottsdaleSteve (Steve)]

My 3XL was out of square when I first assembled it, in exactly the same way as yours is now. The ends of the “X” extrusion were not perfectly square, requiring shims as described in the following old thread:

Yet another xxl squaring issue

I had the exact same issue on my XL, though only a 1/4" gap in the same places (back left/front right). I don’t think you’re shimming in the correct spots. You need to shim the X rail in the places indicated (back of the left end; front of the right end). I used a stack of 3 slivers of aluminum from a Coke can in each spot and it closed the gap exactly. If you look closely, you can see the shim in the second picture. Coke can wall thickness is ~ .004" thick, so with 3 layers my total shim wa…

Not sure why yours went from square to not square, but perhaps it needs shimming…

[DPME (David)]

Thanks - I’ll look in to it.

[LiamN (Liam Newcombe)]

These posts might help

Simple mod to keep your machine square

Getting my machine to cut square and keeping it square has been frustrating me for a while. Even when I spent ages squaring up the frame the cutting squareness seemed inconsistent. So I did what any CNC user would do, modded the machine to fix it Tools required A Shapeoko Calipers A Stick (not calibrated) Optional - 3D printer, or you can use the Shapeoko The Problem(s) The first problem is that it’s pretty hard to get the frame of the Shapeoko really squar…

Measuring belt tension, squaring and calibration

A post about belt tension, how to measure it, what effect it has and why you need to manage belt tension in order to usefully calibrate and square the machine. As usual, no criticism of the machine here, in fact some quite clever design choices seem to have been made. The question of drive belt tension has been bugging me. How much you should have, how to check it and how it affects machine performance. I failed to find any quantitative data to use, so I went and started measuring; and found t…

I’d start by checking the belt tensions.

HTH

[DPME (David)]

Thanks to all who replied. The Coke can shim has got it to sub 1mm which I’m OK with at this time. I’ll spend more time over the weekend checking the belt tensions as per the suggestions above. They have a very similar “twang” sound already, but let’s see how close I can get it

I wonder if this is at all affected by the cold. It’s pretty much freezing in my garage right now and I don’t usually use the CNC in these temperatures!

Can’t wait for the 5 to arrive…

[WillAdams (William Adams (Carbide 3D))]

Yes, temperature shifts will affect this, since aluminum, MDF, and steel all expand/contract differently as the temperature changes.

[dandangerous (Dan Dornback)]

I had a similar problem, both belts seemed tensioned correctly, but one belt had stretched more causing a difference in steps side to side. Belts are cheap and a consumable.

Also check the motor pulleys, those slipping can cause a similar problem.