Looks kinda nice, doesn’t it?
I really like the simplicity of this extruder.
But @Brook_Drumm , what the heck is the third bearing for?
Ugh, there’s my missing bearing!?
J/K, got my kit other day and need to fire up the 'bot to print mine as well.
What is this actually a picture of? Some context would help.
@Len_Trigg It’s a printrbot geared extruder.
http://printrbot.com/shop/gear-head-extruder-v0-01/
@Len_Trigg it the new double gear extruder from printrbot. Filament is fed between two gears with no compression spring. http://printrbot.com/shop/gear-head-extruder-v0-01/
@Rien_Stouten
I don’t have the kit, but looking at it, I’d say the 3rd bearing goes at the end of the stepper motor’s shaft. i.e.: Idler gear is supported by 2 bearings, driven gear is supported on one end by the stepper’s bearing, and on the other end by that additional bearing.
@Carlton_Dodd nope, no room there. The only place where it might fit is close to the stepper housing, but that seems just silly.
Pic shows first version. After some testing we sacrificed the knob in version two for a bearing on the front of the motor shaft. Print the new one and try that. There is even an optional pocket for a 4th bearing on the back on the shaft if you like.
I think there’s a space in the newer (0.02 version) of the mount. https://plus.google.com/115597903227680837543/posts/TAwHFejrfQt
@Brook_Drumm Hm, I think I’m sticking to the first design for now, because I like the knob very much. We will see how that goes.
I have the second version up and running. A real pain to thread filament. Guess I’m not used to running the extruder to start the filament into the extruder. I really like the support of the third bearing, but that knob would be easier. Any way to combine them?
Just bought one. Will report back.
I really don’t like this kind of closed extruders. You have to take it all apart to even see if the filament has stripped?
Two screws and the cover comes off. I hear what you are saying though. It’s a shift away from extruders you can fiddle with… Hopefully, you don’t ever need to.
If the injection molded parts are transparent, that will help you see what’s happening inside.
A+ @walter and could it be scaled to accept welding rod (polymers / alloys)?
Get some thumb screws for the cover??
I’ve been using the v0.02 for almost a week and its doing pretty well. I’ve had a few skips here and there and the closed nature of it makes it hard to see what’s causing the problem, i.e Is the left gear or right gear stuck, is filament stripping, etc. I miss the ability to look in and see why.
I understand. That bugged me at first. Once we get the injection mold done, I will like this extruder better. The needed tolerances are SO tight and demanding for this design, it’s a wonder that they are being printed by a 100 different printers and still work. Your printer needs to be dialed in on all dimensions for this design to work flawlessly.
It’s a little risky for us to release this design as a printed version when a milled version might be safer and perform better but it would be way more money 
Just to be clear to everyone reading along, I bet I’ve had 3 skips total in the time I’ve been testing and I think I’ve printed about 12 different things. I think you are right about the tight tolerances, mine assembled easily but I found that it took a little bit of trial and error to find the right amount of torque on the bolts holding the over over the gears. Cant be too tight or they skip, too loose and it makes a rattle sound. (Probably not a deal breaker but I didn’t want my printer to sound like some jalopy.