Seems like nearly everything I ordered from Mcmaster-Carr is slightly off. The 8mm rod (88625K67) was 3' instead of 1m, which meant I had to buy about twice as many. Local hardware store had something that was close enough, so that wasn't too bad. The springs (9657K108) don't fit over the studding. I'll have to find a replacement. The toothed belts (1679K683) and pulleys (1375K39, 1375K57) don't match the pitch of the RP'd pulleys. Not sure if they're close enough or if they're scrap. I can probably get away with using one pulley and belt for the X axis but I'm not sure about the Y and Z. Has anyone used the McMaster belts with the RP'd pulleys yet? https://reprap.org/forum/read.php?4,10054,10054#msg-10054 Sat, 18 Apr 2026 03:29:44 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?4,10054,10140#msg-10140 https://reprap.org/forum/read.php?4,10054,10140#msg-10140 -------------------------------------------------------
>
> For the motor couplings, I ended up using a
> threaded rod coupling, bored out to the
> appropriate diameters and held in place with a
> couple grub screws.

Here's a picture of one of these couplings in place.

[attachment 582 coupling3.jpg]]]> degroof Reprappers Fri, 07 Mar 2008 08:51:02 -0500 https://reprap.org/forum/read.php?4,10054,10105#msg-10105 https://reprap.org/forum/read.php?4,10054,10105#msg-10105 degroof Reprappers Tue, 04 Mar 2008 14:00:39 -0500 https://reprap.org/forum/read.php?4,10054,10102#msg-10102 https://reprap.org/forum/read.php?4,10054,10102#msg-10102
I saw those (or maybe it was an Oldham coupling) and wasn't sure if that would work, given the shearing force from the belt. I'd probably go with something like that if there were a support and bearing on the non-motor side of the coupling. I'm tempted to rig up some sort of support on either side of the coupling to take the load off it and the stepper motor.


Yesterday, I went wandering around Home Depot with various bits from the Darwin kit, to see what I could use.

For the motor couplings, I ended up using a threaded rod coupling, bored out to the appropriate diameters and held in place with a couple grub screws.

I also found some compression springs that seem like they'll work for the anti-backlash assembly. They were over with the screen door accessories.]]> degroof Reprappers Tue, 04 Mar 2008 12:00:43 -0500 https://reprap.org/forum/read.php?4,10054,10097#msg-10097 https://reprap.org/forum/read.php?4,10054,10097#msg-10097 Forrest Higgs Reprappers Tue, 04 Mar 2008 10:36:25 -0500 https://reprap.org/forum/read.php?4,10054,10095#msg-10095 https://reprap.org/forum/read.php?4,10054,10095#msg-10095
Kyle]]> kylecronan Reprappers Tue, 04 Mar 2008 10:14:32 -0500 https://reprap.org/forum/read.php?4,10054,10063#msg-10063 https://reprap.org/forum/read.php?4,10054,10063#msg-10063
1. Drill out the hubs to 5/16" (or 8mm).
2. Work out a way to couple the Y and Z motors.

I'm leaning toward buying/making aluminum couplings. Both look like they'll be taking a lot of shear and torque stress. Closest I could find off-the-shelf was Mcmaster's part 2424K11. It's a 1/4" set screw coupling but it's only 1/2" OD, which doesn't leave much room for boring out to 5/16". Still, at $6 a piece, it might be worth picking up a couple to try out. I'm planning on ruining at least one pulley by boring them out, so I might as well order the couplings while I'm at it. :-)



//Also the Diagonal ties do not have a grub screw as we found if you tighten the 2 nuts quite tight they will stop the diagonal tie rod from coming off//

I see what you mean. Thanks, I was wondering how that was supposed to work. I just tried it with a couple pieces of scrap and was able to tighten it to where it doesn't slip. Works better with the 8mm rod. The 5/16" will probably need a shim.]]> degroof Reprappers Mon, 03 Mar 2008 09:44:36 -0500 https://reprap.org/forum/read.php?4,10054,10058#msg-10058 https://reprap.org/forum/read.php?4,10054,10058#msg-10058
Also the Diagonal ties do not have a grub screw as we found if you tighten the 2 nuts quite tight they will stop the diagonal tie rod from coming off.]]> Ian Adkins Reprappers Mon, 03 Mar 2008 02:41:55 -0500 https://reprap.org/forum/read.php?4,10054,10054#msg-10054 https://reprap.org/forum/read.php?4,10054,10054#msg-10054
The 8mm rod (88625K67) was 3' instead of 1m, which meant I had to buy about twice as many. Local hardware store had something that was close enough, so that wasn't too bad.

The springs (9657K108) don't fit over the studding. I'll have to find a replacement.

The toothed belts (1679K683) and pulleys (1375K39, 1375K57) don't match the pitch of the RP'd pulleys. Not sure if they're close enough or if they're scrap. I can probably get away with using one pulley and belt for the X axis but I'm not sure about the Y and Z.

Has anyone used the McMaster belts with the RP'd pulleys yet?]]> degroof Reprappers Sun, 02 Mar 2008 23:09:02 -0500