The core is loose

Mostly Printed CNC - MPCNC Troubleshooting
1

As per the instructions, I’m posting here because the core is loose. These are the right size rods and it’s supposed to be snug at this point. there are no instructions for tightening the fit, so I’m here for some help. Suggestions?

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2

Tightening comes after you have both axis’ in. If you printed the new version it should be good once you did that. If not, a little bit of tightening helps (and it is in the build instructions also how to do it).

3

I’m reading from this page: https://docs.v1engineering.com/mpcnc/core/

From the section titled “setting the gantry rails”

In the photo and the text, it refers to a single rail, inserted while on the bench. Here are the bullets from the instructions:

  • Slide the rail in the assembly.
  • The rail should have slight tension and feel good with no nuts in place.
  • All the bearings should be making contact.
    • If your rail is loose or too tight there could be other issues.
  • At this point, put the nuts on. Carefully seat the nuts just to lock in the current tension.
    • A very light touch is needed here. You will be coming back to these so just seat the bolts and nuts.
  • The rails should have a slight drag and feel the same with and without the nuts in place.

The rail does not have a good feeling. It doesn’t touch all the bearings, and has quite a bit of play as in my video. Is all this okay? Should I proceed anyway and put the nuts on?

4

I would just try. You can’t break anything. Did you print the old version? If that is the case, you might have to reprint some modified clamps for it not to wobble.

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5

Hey Jeff,

Did you ever figure this problem out? Mine is doing the same thing and the instructions say to come here as you noted but I can’t really find anything consistent to fix the issue.

Thanks

6

I proceeded. It was sloppy on the bench, but it is all snugged, solid and rolling when fully assembled.

7

Good to know. Thank you very much.

8

Have same issue except nothing is snug when finished still loose.

9

@verveg, what kind of tubing did you use?

10

IMG_20210413_134513
IMG_20210413_1345134608×3456 2.28 MB

11

I had trouble with the 3/4" galvanized conduit from Home Depot. It was slightly too thick for the legs, and for the gantry. I used it for the rails around the perimeter, and it works well there. For the gantry, I upgraded to 3/4" DOM tubing. I got mine from Tractor Supply - Home Depot didn’t have it.