Using a Hobbed stepper shaft for an extruder

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

Edited 1 time(s). Last edit at 05/02/2013 06:34PM by WallyCloud.

So, you actually have the springs pulling instead of pushing?

Looks very clean. I understand this probably won't work with 1.75mm filament, did you consider trying it?

there actually is an old reprap article on how to hobble a stepper shaft. in fact this was a design used for the first mendel.

it is posted here. [objects.reprap.org]

I'd be more intererested in your pinch setup.

Edited 1 time(s). Last edit at 05/03/2013 01:01AM by jamesdanielv.

what hotend are you using?

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@Ohmarinus
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.