I didn’t see anything really related to the issue I am having. On several of the parts that are supposed to hold the nut, i.e. the truck clamp to truck connection, I am finding that the side that is supposed to hold the nut in place without spinning is not stopping the spin. This usually occurs after the screw is in enough that it is impossible to grab the nut with pliers, so the only way I could get at it to redo it would be to tear the entire part apart. I am planning on moving forward so I can start learning and making a few things, but also trying to reprint all the 3d parts with better filament, better settings, etc. What have you guys found is the best way to ensure the 3d printed part holding the nut doesn’t strip out? Is it the filament? the size tolerance? Is there a way to do an embedded nut?
Usually when that happens the hole for the nut is too large, or the nut is not in the hole square so it cross threads as the screw goes in and locks up. I would also suggest running the nuts on screws first before you install. That cuts a thread sorta in the nylon and makes it a little easier.
I haven’t built an MPCNC, but when I had to reassemble my Lowrider I used a little superglue (cyanoacrylate) on each nut and it made a big difference for ease of assembly, plus they can’t fall out of place. The easiest approach I found was to thread a screw in a couple of turns from the wrong side, put a little glue on the sides of the nut, and hold it in place with the screw for a few seconds before then just unscrewing it and leaving the nut in place.
I had this happen to me a couple of times when I built my first MPCNC (Burly), and I attributed the problem to overtightening the bolts. To remove the bolts, I wedged a flat bladed screwdriver against the side of the nut to keep it from spinning. To fix the pocket to keep the nut from spinning, I placed a small amount of baking soda in the pocket and added some thin superglue.
For the nylock nuts, back when I was building my Primo, I found it very useful to thread the bolt/screw through the nylock nut firsf, before putting the nut in the assembly. This reduced the torque that the nut put on the plastic when doing the actual assembly. A bit of extra work, but after spinning a couple of nuts, this helped.
For the nuts already spun, a pair of long tweezers was generally enough to hold the nut and remove it. I then fixed the opening. I used various methods, a coolish soldering iron and filament (messy, hard to control, but solid where the surface wasn’t important.) Baking soda and superglue did a good repair.
Most of those nuts got pressed in with a drop or two of epoxy, though.
Thanks for your replies, I am going to try the methods described. Hopefully, I can repair the nuts in question without complete disassembly!