Unlocked Z Nut Lock

I was just about to make some foam dust, when the entire Z axis fell. Is the nut just held up there with friction? I have mine completely tightened, and it’s still loose enough to pop out when I’m raising or lowering it. I did install the smaller hole up, with the gap on the left side when looking from where the tool is.

I see now that there are two versions… I wonder which one I printed… The gcode doesn’t have 11mm or coupler in the name, so I’m guessing that’s the not-11mm one. And I bought the kit. I’m not sure which size nuts you put in there.

So how many mistakes is that? 1 or 2?

Images, because I took them:

I guess I’m pretty lucky that it didn’t happen right after cutting the foam. Better to find these when the tool is off.


I have the same problem. One of these days I will remove it to see what is going on, and I will print another. To remove it I will need to take apart most of the Z assembly. My quick fix was I wrapped a few layers of masking tape on the long coupler nut and I could get the top screw to hold it snugly. As my favorite handyman philosopher Red Green once said “This is only temporary… unless it works”.


Thanks. I am printing one of the 11mm ones. I looked at the STLs and the one without 11mm in the name has a bigger hole, so that would explain it.

Considering everything else I’ve printed holds the parts without the set screws doing anything, I think I must have misconfigured it.

I think I can get to it without taking everything in the Z apart. Specifically, the pipes going into the Z motor mount and the tool holder are the hardest parts, and I think I can turn the threaded rod enough to get to the two Phillips screws, and then I can lift the whole thing out of the bearings. I’ll let you know how that goes. I should have some time tonight or tomorrow night to try it.

Let’s just hope your solution doesn’t end up becoming temporary after doing one of these :slight_smile: :

I’ve done that a couple times now. I found that I can stick a flat bladed screw driver under the lock nuts to hold them in place while backing the screws out. Putting it back together is a pain though.

I took it apart, and sure enough, I have the wrong sized nut lock on there. I’m printing one of the 11mm parts (And I went with 100% infill, why not)?

It is going to be a pain to keep those nuts tight on the back, since it’s so hard to get a driver back there once the pipes are installed. You might be right, Dave, this might end up needing a lot of dis-assembly :slight_smile: At least I didn’t have to get the Z Axis pieces away from the Z motor holder, that was really difficult piece to get in there. Also the Z shaft coupler…

One of those goofy looking bent needle nosed pliers seems to work to hold the nut and get it started. Still had to jam it with a screwdriver to tighten though. The bottom one is all OMGWTF I’M GOING TO KILL SOMETHING! lol

OK, I have the 11mm version, printed at 100% infill (and 0.1mm layer height, oops). It fits snug, but not tight :slight_smile: . It only took me about a half hour to replace it, because I only had to remove the spindle, and then unscrew the whole thing straight up. Thanks for the help, I’m onto my next issue.

I know, I have had to replace a few of them myself. Sorry about the crappy design of that. I get so pissed at it I don’t use the lower nut at all, Just the screw. does that make me lazy?

Instead of trying to make a better nut trap I just started from scratch. I am working on the nut lock part now, but better believe I will make it easier to get at this time around. And maybe get rid of the anti backlash I think a coupler nut is plenty.

Here’s a sneak peek.

That looks great. I like that you have the left and right sides touching the Z pipes symmetrical. That should add a lot of strength, plus, it looks cooler. Seeing it without the nut trap, I can see why that’s difficult to get attached. So are you making it attach to the 4 (or 2 of the 4) nearest bolts, instead of using the small screws?

I was sort of surprised when it fell down, because I thought it would have had a physical trap, not just gripping it with friction. But once I printed the correct size, it seems to be very sturdy.

If you end up with a silly nut like that again, maybe you could design a wrench that I could print to help me out :).

N/M. I just solved all your problems. Check out my sweet CAD skills.

That’s awesome, I need that CAD program. You are right though kinda. I think I am actually going on the other side of that black piece. I will make a large hole though it and bolt a nut trap underneath it. I think. Considering a piece that actually spans the gap and connects the black pieces to increase rigidity a bit, maybe. If I go on the other side of the black piece it opens up the tool holder area for a closer more rigid tool connection.

The other one doesn’t have a physical trap because world wide all these dam coupler nuts are different lengths, and widths. I also need to make sure there is room for the people that will use a leadscrew as well. Really though in the beginning when I originally designed it I/we were using the flex shaft tools with almost no weight at all so that connection was overkill.

Thanks. I made it in Autodesk Painter. It’s pretty good. Only works on Tesla dashboards though, and it’s like $15k.

That whole redesigned middle section looks SAAAWEEET. Have you considered incorporating a version of the camaro mod to add a 3rd set of bearings the x and y right out of the box?

Thanks. I do like his over the pipe design but I don’t think more bearings is the answer. I tried putting the other bearings over the pipe but it adds a lot of plastic and I’m not sold on that direction. If you want to go that direction just add another one of the large red pieces on the other side and some longer bolts or allthread, easy.

This gets rid of the weakest middle joiner parts and really sets things at a good 90 degrees. 2 birds…

When do you anticipate this middle design to be available?

One other idea… Could you include the z nut trap as a part of that middle section since it is one piece in that model?

That’s a tough one. Depends on how much free time and printer time I can squeeze in.

I’m happy with the X and Y part of it, I hope to work on the Z nut lock tomorrow. Then there is the Z motor mount, and the tool mount to do, then a few tool holders. It could be a while. I am picking up momentum so don’t hold me to it but maybe 2 weeks? I need to print and run it to make sure it is actually better.

I will put it up in the forums first, hopefully a few of you brave souls will give it a go, then release it to thingiverse, then update the assembly directions.

I have new corner blocks done as well. Just need to make some better feet to go with the new corner assembly.

Haven’t started the rollers yet but I will release them before that.

All in all, hopefully a little more rigid, print a little better/faster, 3 sizes (or more 23.5mm, 25mm, 25.4mm).

Well I may be one of those brave souls (concerning the middle z stuff)… I am still waiting for my bearings, boards, drivers, and various other parts to arrive from china. I think that design looks like it might be better then the current.

Not sure how the Z motor mount could be changed… It does what it needs to. Or is the spacing different between the vertical conduits?

Yeah the spacing is different. Each size is different as well, in my solidworks it is kind of parametric now ( I have a few issues so I can’t just make 10 different sizes that easily) but everything is at minimum spacing so I just update the tube size and fix the bad stuff and boom done.

I shall patiently await the new design

Not me, I hate waiting.

You motivated me, so I am finishing up the new z nut lock now, that will pretty much finish up that assembly. Print parts tomorrow. Pretty happy with it if it works! Difference hardware wise is no more 1.75" or 3" bolts and 5 3.5" bolts instead, 1 screw and nut for the z nut lock and it is trapped on the bottom instead of the top, easily tightened or swapped out!

Then work on the z motor mount.

You are welcome for the motivation LOL!!! Don’t forget to get some sleep in there.