Z axis problem - threaded rod fouling bolt heads.

Hi Folks, I hope someone can point me to the cause of my woes! A friend has kindly printed all of the parts from my machine, I beleive he used the IE parts from thingieverse. The problem that I have is that the threaded rod is fouling on the bolt heads for the Z axis bearings and causing me to lose steps due to the excess drag on the rod.

My gut instinct is that something isn’t printed correctly , perhaps the Z nut lock causing the rod to lie to close to the gantry?

The lower 2 bolt heads are the worst offenders and I have ground down the heads on those quite a bit but it hasn’t fully cured the problem, the top most one doesn’t quite foul the rod but its close, can just about slide a business card inbetween the bolt head and the rod but that’s all.

Any help with this would be gratefully received



There are 2 znut holders 11mm and 13mm flat to flat, since you are at an angle makes me think you have the wrong one on there.

I’m seeing the exact same issue. Doh, posted to the Assembly section earlier and my Google-Fu sucked so I didn’t find this until stumbling across it… anyway. Yeah, same thing. The 11 vs 13 mm Z Nut Lock doesn’t SEEM like it would be the answer, at least for MY problem, but I will certainly try printing the Z Nut Lock 11mm first thing in the AM (if I fire up the printer at this hour the wife will brain me) and see if that resolves my problem… but MAN is that thing gonna be a BITCH to change without having to disassemble the entire middle assembly. It’s fscking BURIED in there!!! {sigh}

Well i performed surgery on it in-situ which was a bitch but doable, and inserted a couple of washers between the lock and the gantry to pack it out a mm or so, much better. Time will tell if this is an effective cure though or if it will lead to Z inaccuracy and need a better fix.

Slightly related, I have found that the znut holder seems like a weak point in the design. It seriously difficult to swap out and is easy to snap the screws out the side. I have modified it to beef up the margins between the screw hole and the outer edge. A future redesign would be nice. Maybe have the bolts flipped around and held captive within the z-middle. Then to mount the znut, you push it down on to the bolts and thread the nuts. This would allow servicing the znut without tearing the whole machine apart.

Attached are my modification to the znut. Though, I should have slanted the outter edges to not collide with anything.

I had the same problem. I lifted out the Z and used my hobby drill with cutting disc.
I just shaved off the edge of the bolt heads. take your time(start stop) though as heat can build up and you don’t want to deform any of the printed parts.