Z axis slop?

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This topic contains 12 replies, has 4 voices, and was last updated by Profile photo of Ryan Ryan 2 weeks, 5 days ago.

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  • #35225
    Profile photo of Dalton Porter
    Dalton Porter
    Participant

    Greetings friends,
    Please check out this youtube video of the amount of slop in my z-axis.

    I’ve done some good looking cuts, but I want to know is this way too much play?
    If so, which nuts to tighten? I’m afraid to start tightening things without a game plan for fear of cracking some parts.
    I don’t have a 3D printer to make replacements.

    Thanks.

    #35248
    Profile photo of Ryan
    Ryan
    Keymaster

    That is not right at all, can you measure your rails? There is no way they are the right size. What sized printed parts do you have? Even if I put the smallest rails in the largest parts I don’t think that would happen.

    #35249
    Profile photo of Ryan
    Ryan
    Keymaster

    That is not right at all, can you measure your rails? There is no way they are the right size. What sized printed parts do you have? Even if I put the smallest rails in the largest parts I don’t think that would happen.

    Maybe measure those bearings as well, something is fishy here.

    #35251
    Profile photo of Dalton Porter
    Dalton Porter
    Participant

    I measured a US quarter at 26.16mm for calibration. My calipers might be off by .1mm.

    I ordered the 23.5mm printed parts kit.

    The z-rails measure 23.45mm

    The bearings measure right about 22mm.

    The bolts that appear to be for tensioning the z-axis spin when turned by hand. I mean, there is very little to no tension on them. (see video).

    #35255
    Profile photo of Ryan
    Ryan
    Keymaster

    Did you print the parts yourself?

    #35256
    Profile photo of Ryan
    Ryan
    Keymaster

    The rollers are snug, and the z axis clamps fit tight?

    #35257
    Profile photo of Ryan
    Ryan
    Keymaster

    The bolts you are spinning in the video are the ones that control the tension for the z axis, top and bottom so you can tighten those a bit. What is throwing me is normally it is a snug fit even without tightening them.

    #35261
    Profile photo of David Walling
    David Walling
    Participant

    I’ll second Ryan’s ‘snug fit’ comment.

    I remember my z-axis barely fitting inside the bearings with the bolts all the way loosened.

    1 user thanked author for this post.
    #35263
    Profile photo of Dalton Porter
    Dalton Porter
    Participant

    Ryan, I bought all the parts from you. the 23.5mm set.
    I suppose I can try to tighten those bolts. Maybe my EMT is slightly smaller than normal? Or is it possible the parts printed slightly too big?

    #35273
    Profile photo of Ryan
    Ryan
    Keymaster

    The parts should be good, same printers same gcode as always. the parts should all have a “c” in them to verify they are the right ones. If your corners, locks, feet rollers all fit correctly the parts are good, never actually had bad parts. Something is up with the middle. Is your z axis all good when laying it on a flat surface, no twist as shown in the instructions? Tighten up those bolts and see how it goes.

    If not, just take apart the center and put it back together, for whatever reason the second time around fixes most people’s issues.

    1 user thanked author for this post.
    #35347
    Profile photo of Dalton Porter
    Dalton Porter
    Participant

    I think I followed your “get it flat” instructions pretty well.
    I tightened up those bolts, upper and lower, and that removed the slop. It seems pretty rigid now. Bearings making good contact.
    I tightened the bolts until I could not turn with my fingers, then starting doing 1/8 turns just until the slop disappeared. I didn’t want to hear any cracking noises.

    Thanks for your help guys.

    #35354
    Profile photo of Bryan
    Bryan
    Participant

    Mine was the same way when I first put it together but I tightened those bolts until the bearings all made good contact with the conduit. Now its super rigid but has smooth vertical movement. Make sure and get the top ones and bottom ones. If you are using a modern PLA it shouldn’t crack. The stuff I’ve been using (Hatchbox, eSun PLA+) has a flex similar to ABS. In fact if you really torque it they turn white and stretch like ABS instead of cracking like old types of PLA (which just snaps). I cranked down the leg clamps and such pretty good without any cracking at all.

    #35361
    Profile photo of Ryan
    Ryan
    Keymaster

    Sweet Progress!

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