0.2mm off square

Hi All,

I’m switching to a thread hole bed and am checking how square my Shapeoko XL is. When making the threaded bed you have to drill the holes from the underside so I want to make sure when I flip the board it will be square.

I am using a 120mm saddle square against the front of the frame, lining up a bit to the end of the square and then trimming left to right. I have run through the usual things and got down from a visible gap to 0.2mm. So the left is 0.2mm further forward than the left. That’s determined by having to jog the bit 0.2mm before it touches the square, when compared to the other side.

In general this amount doesn’t both me but to create the threaded bed I think I will end up doubling this amount on every object I work on…

Any thoughts would be appreciated.


Welcome to the rabbit hole Ben :wink:

The first thing is, are you really going to be using threaded bolts as the X, Y alignment? A thread isnt the cleanest thing to butt up against. You could consider drilling a series of locator peg holes in the board once flipped the right way up for location and keep the threaded inserts for clamping. Also, when you drive those inserts in, I won’t be surprised if they’re off centre by more than 0.2mm.

As for square-ness of the machine, have you watched Winston’s YT videos?

I’d first check whether your front frame is actually square with your Y axis on the machine as there’s nothing that really forces that to be the case. If not then you’re chasing your tail in these measurements

You could do the corner to corner measuring thing and then pull the frame squarer, I used a very large sash clamp but ratchet straps and others work too.

What may be happening is the ends of your X rail might not be completely square and you could shim them (that’s what I had to do).

Also, if you’re going to be concerned with precision, you may need to calibrate the travel distance X and Y as well, I found that my XXL was about 1mm longer in the X than the Y over 800mm so things weren’t actually “square”.



Thank you, thank you, thank you!

I am actually trying to dig myself out of the rabbit hole after deciding to upgrade to the HDZ, steel belts and a new cabinet (because of the added height of the HDZ). Which resulted in 9 months of pontificating and no use of my Shapeoko! The only positive is I got pretty confident with my 3D printer and there’s a lot of shared knowledge.

Back to the thank you. I completely missed the fact that the holes do not need to be square! It might be obvious but someone needed to point that out to me!

That said I do plan to use Carbide’s new corner square, but after a quick inspection, I see it has a good amount of play. So setting it square should be no problem!

Anyway, thank you, I can confidentially route all the holes now and get my machine back into action!

Yes I probably should re-watch the videos and go through the full squaring process but, as I said, I am going to focus on a machine that functions, not a perfect machine that is never ready to be used :slight_smile:


So precision and repeatability are vapor ware. One time you see it and the next time you dont. A more important question to ask is what are you going to machine. If you are making signs and v carving on wood then you are already precise enough. If you are going to machine rocket engine parts you are machining on the wrong machine.

There is nothing wrong with trying to get precision and accuracy but you need to define your tolerances and more important why those tolerances were chosen. Dont drive yourself crazy with measurements. Makes some projects and see if they are acceptable. A few thousands (.2MM=.007") is pretty close for horse shoes, Shapeoko and hand grenades. So what are you trying to achieve and why are you trying to achieve it.

If you are going to make a threaded spoil board .2mm is not much off considering the hole and clamp have more than much slop. If you make wooden clamps or L brackets the holes drilled for the bolts have to be slightly oversized. This introduces a lot of slop into the positioning of your work piece.

You know, after watching Elon yesterday, I’m working on a rocket :slight_smile:

1 Like

Well that’s brightened up my day :wink:

Yep, this :wink:

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.