So I printed my extruder before I had my hobbed bolt, and now that I have both, the nut cavity in the extruder gear is a bit too large for the bolt head. There's just a bit more wobble than I'd like, especially since I'm using retraction. Actually, in any event, it would seem to be to be best with no wobble whatsoever. So I had thought to put some epoxy (specifically JB Weld) into the cavity before assembly, and let it harden around the nut head, but I don't like the idea of using epoxy like this. To me it's too irreversible, and since the gear won't last forever, I wanted to make sure I could easily extract the bolt at some future date. I could always print another gear with a smaller cavity, but it would be a shame not to use this one, especially because it turned out to be of excellent quality. Could anybody offer an alternative to the epoxy? Thanks https://reprap.org/forum/read.php?151,229723,229723#msg-229723 Mon, 14 Sep 2026 02:30:13 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?151,229723,235090#msg-235090 https://reprap.org/forum/read.php?151,229723,235090#msg-235090
This has provided a reliable interface between the bolt and extruder gear on my RRP mini extruders after the bolt head initially worked its way loose in the recess in the big gear that it should have stayed in.]]> speedeep General Mendel Topics Mon, 12 Aug 2013 13:27:25 -0400 https://reprap.org/forum/read.php?151,229723,234601#msg-234601 https://reprap.org/forum/read.php?151,229723,234601#msg-234601 mjrice General Mendel Topics Sat, 10 Aug 2013 18:03:48 -0400 https://reprap.org/forum/read.php?151,229723,233347#msg-233347 https://reprap.org/forum/read.php?151,229723,233347#msg-233347 jbernardis General Mendel Topics Tue, 06 Aug 2013 15:14:11 -0400 https://reprap.org/forum/read.php?151,229723,231661#msg-231661 https://reprap.org/forum/read.php?151,229723,231661#msg-231661
good luck]]> bigfilsing General Mendel Topics Thu, 01 Aug 2013 03:24:36 -0400 https://reprap.org/forum/read.php?151,229723,231166#msg-231166 https://reprap.org/forum/read.php?151,229723,231166#msg-231166
I had exactly the same problem, and I temporarily solved it by making my hex head bigger with electrical tape. I say temporarily because the tape will eventually slip out, but it gives you plenty of time to print a new gear with exactly the head size you need. If you need an appropriate stl or scad file, I can help.

The other approach I've seen people use is for the nut to sit in the hex hole on the gear. In fact, I think this might be what was intended, though from an aesthetic perspective, I don't like it. :)]]> Karmavore General Mendel Topics Tue, 30 Jul 2013 11:35:06 -0400 https://reprap.org/forum/read.php?151,229723,229837#msg-229837 https://reprap.org/forum/read.php?151,229723,229837#msg-229837 jbernardis General Mendel Topics Thu, 25 Jul 2013 09:46:54 -0400 https://reprap.org/forum/read.php?151,229723,229738#msg-229738 https://reprap.org/forum/read.php?151,229723,229738#msg-229738
I should point out that generic clear 5 minute epoxy comes off easily with a bit of heat. It becomes soft like wax over 100° celsius or so. JB Weld withstands more heat(250°C?) than that, so it might be harder to take off.]]> Yvan General Mendel Topics Thu, 25 Jul 2013 02:25:42 -0400 https://reprap.org/forum/read.php?151,229723,229723#msg-229723 https://reprap.org/forum/read.php?151,229723,229723#msg-229723
So I had thought to put some epoxy (specifically JB Weld) into the cavity before assembly, and let it harden around the nut head, but I don't like the idea of using epoxy like this. To me it's too irreversible, and since the gear won't last forever, I wanted to make sure I could easily extract the bolt at some future date.

I could always print another gear with a smaller cavity, but it would be a shame not to use this one, especially because it turned out to be of excellent quality.

Could anybody offer an alternative to the epoxy?

Thanks]]> jbernardis General Mendel Topics Thu, 25 Jul 2013 00:29:09 -0400