Hey guys, I hobbed a steppers shaft and have been using it for a while now to direct drive 3mm. It works great and is excellent in simplicity. I thought I would write it up so that people can see that it can be done. The much smaller filament drive radius you can achieve gives the stepper way more torque so that driving 3mm is easy with a 43Ncm stepper. I also found it easier then making a hobbed bolt. Here it is: http://reprap.org/wiki/Hobbed_Stepper_Extruder Thanks, Wally https://reprap.org/forum/read.php?1,204938,204938#msg-204938 Tue, 17 Mar 2026 02:18:28 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?1,204938,205073#msg-205073 https://reprap.org/forum/read.php?1,204938,205073#msg-205073 Nah the springs are pushing, you just slot them in there when its apart. I don't have a 1.75mm hotend or filament so I haven't tried, I figure they use a smaller groove and tap for 1.75 but I don't know.

@jamesdanielv
Ha, never found that when I was looking for people who had done this, interesting. The plastic pin on the right hand side moves in a slot, so as the left hand bearing moves down (from say 11 to 9 o'clock) it pulls the right hand bearing in. I will post some pictures with the front arm removed soon but I found something which I need to fix.

@thejollygrimreaper
Its just a mendel-parts.com v9.]]> WallyCloud General Fri, 03 May 2013 09:08:05 -0400 https://reprap.org/forum/read.php?1,204938,204971#msg-204971 https://reprap.org/forum/read.php?1,204938,204971#msg-204971 thejollygrimreaper General Fri, 03 May 2013 00:01:02 -0400 https://reprap.org/forum/read.php?1,204938,204967#msg-204967 https://reprap.org/forum/read.php?1,204938,204967#msg-204967
it is posted here. [objects.reprap.org]

I'd be more intererested in your pinch setup.]]> jamesdanielv General Thu, 02 May 2013 23:28:40 -0400 https://reprap.org/forum/read.php?1,204938,204945#msg-204945 https://reprap.org/forum/read.php?1,204938,204945#msg-204945
Looks very clean. I understand this probably won't work with 1.75mm filament, did you consider trying it?]]> Ohmarinus General Thu, 02 May 2013 19:21:31 -0400 https://reprap.org/forum/read.php?1,204938,204938#msg-204938 https://reprap.org/forum/read.php?1,204938,204938#msg-204938
I hobbed a steppers shaft and have been using it for a while now to direct drive 3mm. It works great and is excellent in simplicity. I thought I would write it up so that people can see that it can be done. The much smaller filament drive radius you can achieve gives the stepper way more torque so that driving 3mm is easy with a 43Ncm stepper. I also found it easier then making a hobbed bolt.

Here it is:
http://reprap.org/wiki/Hobbed_Stepper_Extruder

Thanks,
Wally]]> WallyCloud General Thu, 02 May 2013 18:33:13 -0400