Reply To: Can't get Center Assembly Square XY direction

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Morten Nielsen


The “adjustment” bolts don’t slide around inside the hole for adjustment, they actually flex the parts and squeeze the bearings against the pipe, if need be. I think you’ll be okay after a few runs, once everything has worn in. just remember not to tighten down any of the bolts yet. your bolts should be tight enough to snug up the bearing but still be loose enough that they turn freely… if that makes any sense.

Tight, snug loose:
I’ve tried different ways.. both very loose and very tight.. my bearings always turned fine regardless of how much I’ve tightened it.
In no way can the bearings be move away from touching the Conduits – After I enlarged some holes a lot I could do this… I know some of them are not straight, which makes the issue worse, so had to enlarge them even more to make some wiggling room.

I hear what you say. And it might work. I’m just not sure what you say regarding adjustment is spot on… Or at least the instruction is VERY unclear to me.. Viscious1 is in this thread, which is nice, but we seem to have different views on what is clear or not; I personally find the entire instruction very unclear with no clear correspondence between text and images :
I lack some visual references on the photos, as to the bolts we talk about, and better description of function of said bolts.

I started out with all bolts (A, B, C) very loose, but it really made almost no difference between being loose and tightened up. All my parts fits snugly together without bolts.. Not so tight as they stay put without bolts, but enough to not leave any wiggling room.

In the assembly instructions it says:

First check that the X and Y rails are equally tensioned in the XY blocks, all the bearings should make contact. If you need to add any tension start with “Tension Bolt A”, at this point it is best to leave “Tension bolt B” loose (it locks the assembly in place as well as rail tension).

Second step is to make sure the Z rails have equal tension and all the bearing are making contact. If you need to add any tension use the “Tension bolts C”

How I understand it, and please correct me If I misunderstood it, the bolts do 3 things:

  1. Tighten the parts together (obvisouly)
  2. Adjust bearings if they do not touch the rails – So there must be some movements in the mountholes? – Mine has none, and in fact had to drill up the bolt holes to even get bolts through it. (holes are 8~8.2mm when measured in STL file, which means they has to be drilled in most cases)
  3. Make adjustments by tightening the parts in special sequence – what sequence?

    Worn in after a few runs
    How do you mean it should be worn in? Problem really is that the top and bottom F-XYZ parts are pushing the F-ZY parts a bit too far apart (outer edges), meaning the XY cross-conduits are not square.

    When I turn on my controller it locks the drivers, which means I could turn it off, make the Assembly square and then turn controller on.. it would be square now… I could run it like this, but I do not see how it should wear F-XYZ in any way to fix the problem? (problem: open up F-XYZ)

    Pre-checking before each run:
    Yea, I can see how it is needed, but as it is now there is a 1-2mm gap from inner to outer end of my rather small Square.. that is a lot in the big picture.
    My primary 3D printers are UM2 clones, so I do know the how the mechanics works.

    Squaring tool:+
    What is the distance between center to center of XY rods (the 4 outer rods)
    Asking as I’ve wanted to make some squaring tools as I use for my Ultimaker machines, but correct distance would be nice 🙂