X axis “twist” when setting up

Just installed my HDZ and upgraded the belts and wheels. Doing some fine tuning and squaring and noticed this and am not sure of it’s an issue or not.

When the x axis Is all the way forwards and against the frame I can hold one side and push the other side away from the frame 4-5mm. I can reduce this by tightening the v Wheels on the Y carriages but to eliminate it they need to be really quite tight.

What is the correct approach here? Thanks

Hi @scottybeefs,

How close to square are you when you bring the X rail forward, before doing your push-one-side-only test ?

Out of curiosity I just tested on mine, when I move the X axis to the front manually it contacts the front plate on both sides at the same time, and then if I hold one side and push the other (gently), it will move by about 1mm max. BUT, I have the SO3, so on an XL or XXL with X axis twice as long, this might translate to 2mm or so, someone else could confirm.

The Y vwheels should be tight against the Y plates, but indeed you should not have to adjust their tightness (via the eccentric nuts I mean) against the Vrail to compensate for what you are seeing, the bottom v-wheels should be tightened just enough that they don’t slip on the rail when turned manually, as you know.

Maybe have a go at re-checking the squaring of the machine? (but then again you said you just did…)


Thanks Julien - it’s pretty square, I just redid it the other day, photos below.

I can still get it to defect by 2mm when pushing on it, the v wheels are what I consider to be too tight though.

I just backed off the eccentric nuts so the v wheels are adjusted as per what you suggest above and I can get the x axis to deflect by 7mm without excessive force…? Be interested to know what others with an XXL see?

Right side

Left side


Is it really an issue if you can push the sides manually when power is off?
As soon as the motors have power it should be really hard to twist the X axis.


Yeah fair call on when the motors are on. And yeah I suppose that’s my question, do I need to address it or not?

Hey Scottybeefs. I have an XL and when I manually bring the gantry forward both of my plates aren’t in contact - my right side is off by a few millimeters, maybe five? (I’m away from my machine for the weekend).

When I measure between Y-axis rails, they are parallel; and when I measure diagonally, the distances between corners are virtually the same. The aforementioned measurements were measuring tape accurate. I suspect my X-axis extrusion ends weren’t cut square since I can loosen the bolts and get the gantry plates to touch at the same time. Having said all that, I don’t have any perceptible issues. My holes are round and my lines are straight, parallel, and perpendicular when I design them that way.

In my opinion, if you’re only 2mm off but your rails are parallel and diagonal measurements check out, I’d get back to making. If you have issues with your projects then I’d revisit.


Thanks for the Brian - it only deflects 2mm when the v wheels are over tight, it’s 7mm when they are the correct tightness.

I think Nils is correct in that it shouldn’t matter once the motors are engaged though so I’m going to roll with the more “correct” v wheel tension option I think

Do that for sure. Having the vwheels “just tight enough”, a square machine (which yours is, perfectly, judged by those pics), and the motors doing their thing should make for very precise cuts.


In my long winded response, I meant to say that I agree with having the wheels tensioned “correctly” too.


I checked my XXL, holding one side of the X extrusion pinned against the bed frame and applying a counter force to move the X extrusion, I get less than 2mm of movement.

V-wheels are adjusted by equal friction slippage.

Thought I share my comparison.


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