This is my first build, and I’m really excited to get it working. I also 3D printed all the parts myself.
I’ve been running into an issue where the nut is stripping out the 3D printed part, making it impossible to tighten properly. For example, the nut that secures the temp strut to the brace, strips the print and causes the nut to just spin freely where it’s supposed to sit. This means I can’t tighten the temp strut enough so that it doesn’t move back and forth and sit flush against the brace. It’s also made it harder to remove the bolt and nut afterward.
This also happens where the the brace is supposed to clamp on the pipe. It strips the print before I can tighten snug enough, much less get a chance to overtighten.
Here are a few things I’ve tried:
Reprinted the brace with stronger walls and 100% infill around the nut capture area.
Added material (like tape or filament) around the nut to try to hold it in place.
Verified that the bolt is threading into the nut correctly and not cross-threading or stripping.
I’m considering using CA glue to secure the nut in place, but I’m not feeling very confident that will work either.
Are the print tolerances OK? Is the nut free slipping inside the hole or you have to fight with it to get it seated? For braces I had to apply a bit of force to seat the nut, but it had no change to move somewhere, my prints are on the tighter side.
Also note that threading itself can generate enough heat to melt the pla and cause the nut to slip. It didn’t happen with any of the stock parts of the cnc, but when seating a nut for one of my off prints, I applied too generous force and the heat generated by screwing literally melted the pla and made the nut slip.
I agree with this. The problems you are having seem like the hole where the nut goes is way too loose. You might need to do some printer calibrations to get them to print the correct size.
Also make sure your slicer isn’t applying hole compensation or anything like that making them larger.
I’d say the print tolerances are pretty good for the most part. I did have to push the nuts in for other parts, like the YZ plates but I didn’t have to push it in for the braces, so that makes sense.
I can maybe try to add some modifiers in the slicer to increase the size of that hole. I’m using an X1C with BambuStudio by the way.
Make sure you have enough walls when slicing, I think I used 3 walls. For sanity sake, and I know it sounds ridiculous, but recheck that you have M5 nuts and bolts. An M4 will fit in the hole, if the print is on the tight side it might seem ok, but will strip instantly.
Pre thread, even multiple times the nylon lock nut, to lower the resistance. Try to thread the M5 screw without the nut in the brace, do you have any resistance that might cause issues?
I don’t have any trust in CA glue either, but I think there have been instances where you mix the CA with baking soda and it cures stronger. I would consider it a last resort.
Also, check how the tubing fits, you might be able to deduce tolerances from both the tubing hole and the nut hole.
Hopefully you’re not using an electric driver or drill at any point on the fasteners- the friction can melt the plastic in the nylock and you’ll never get the bolt out again without a socket on the nut - I learned that the hard way on my mpcnc build.
