Spur Gears for Printrbot (Printed Extruder)

by Drawcut, published

Spur Gears for Printrbot (Printed Extruder) by Drawcut Jul 4, 2012
13 Share
Download All Files

Thing Apps Enabled

Order This Printed View All Apps


Liked By

View All

Give a Shout Out

If you print this Thing and display it in public proudly give attribution by printing and displaying this tag.

Print Thing Tag

Thing Statistics

30735Views 11500Downloads Found in 3D Printer Parts


This is a set of spur gears for the Printrbot extruder. The original herringbone gears of the PB are not well suited for the application, IMO. The herringbones are sensitive to misalignment and give few benefits in return. The small spur gear is made wider then the large gear to allow for axial misalignment. The hubs are taken directly from the original Printrbot STLs. Gear ratio is the same as original. I have not yet printed or tested these yet but they seem to slice OK in Slic3r 0.8.4.

Technical Data:
Diametral Pitch: 18
Pressure Angle: 20 deg
Small Gear (pinion): 13 teeth
Large Gear: 43 teeth
Addendum Modification Factor: 0.35
Solidworks files are 2011 version.

Update: 05/07/12: -Deleted- See Update 3.

Update 2: A PB plus user has printed and installed these with good results.

Updated 3 (06/07/12): These gears should work for any of the Printrbot printed extruders. (PB original, LC and Plus) There may be some variation in some of the PB supplied parts out there but these are sized for the official released extruder.

Note: Brook has mentioned a new laser cut extruder he is working on. Unknown what the gears will be on that.

Update 4: 07/08/12: Added V2 of the large gear. Only change is the web section has been changed to full depth spokes. V1 parts will mesh fine with V2 - gear teeth are the same. My sample parts are printed at .4 layer height and my bot obviously needs some tuning ;)

Updated 10/7/12: Added fixed versions of the V1 parts. Fixed by using Netfab's cloud service to get rid of the non-manifold conditions.


Print and assemble the same as you would for the original parts.

More from 3D Printer Parts

view more

All Apps

Auto-magically prepare your 3D models for 3D printing. A cloud based 3D models Preparing and Healing solution for 3D Printing, MakePrintable provides features for model repairing, wall thickness...

App Info Launch App

Kiri:Moto is an integrated cloud-based slicer and tool-path generator for 3D Printing, CAM / CNC and Laser cutting. *** 3D printing mode provides model slicing and GCode output using built-in...

App Info Launch App
KiriMoto Thing App

With 3D Slash, you can edit 3d models like a stonecutter. A unique interface: as fun as a building game! The perfect tool for non-designers and children to create in 3D.

App Info Launch App

Print through a distributed network of 3D printing enthusiasts from across the US, at a fraction of the cost of the competitors. We want to change the world for the better through technology, an...

App Info Launch App

Quickly Scale, Mirror or Cut your 3D Models

App Info Launch App

Treatstock is an online platform that offers decentralized manufacturing services such as 3D printing and CNC machining for clients all over the world. We offer free and instant access to comparati...

App Info Launch App

3D print your favourite design with NinjaPrototype, a professional 3D manufacture with consistent quality and speed.

App Info Launch App

Out of curiousity, what tooth profile is this?

These are Involute profile teeth which is very typical for spur or helical gears.

Any particular reason for the V2 large gear with the full-depth spokes? Flex issues with V1?

I have not seen any flex issues in use, but I thought it could be a potential problem. That or possible warping / shrinkage during printing. Most traditional gears would have full width spokes like the V2 large gear and I also like the look better. YMMV.

great stuff, my original gears were grinding themselves and I got a qubd extruder, it's smaller and works great, and is at 0.35 nozzle.. but.. I used it to print new gears for the printrbot extruder, which seem to mesh perfectly.
it'll be the first part of a new printer which will make a great backup or present for someone.
thanks for making these, I love it when things get simpler. :-)

Had several people tell me they had trouble printing with non-manifold errors.  The fixed V1 parts should take care of that.  (Should have listened to PxT earlier.) 

Just finish printing the large spur gear at .2mm layer height. Bolt fits like a glove and gears mesh really smoothly, no bind at all. Good job!

Both of the V1 files use part of the original Printrbot STL files and Slic3r gives a non manifold warning, but they seem to slice and print fine. I'm not sure if fixing them with Netfabb really gains you anything, but I doubt it would hurt.

The error seems to come from the original files. Seems like a lot of files made from Sketchup have this issue. The V2 large gear was made entirely in Solidworks and doesn't have this problem.

The STL files are non-manifold, Slic3r complains about them. Netfabb fixes them up though.

Hi Drawcut,

Thanks for taking the time to make up these gears, I printed out both gears the L Gear is perfect but the S Gear center hole is a bit to large, mine printed with a 3mm radius and the motor shaft looks to be about half that size, could you post a V2 with a smaller radius for the motor shaft hole ab
out half the size it is now.....thanks....

Recalibrated my printr and reprinted the gears and the are working great. I find that my extruder motor is not running as hot any longer. Thanks again for putting these gears together for the community..

Glad you got it straitened out. I was starting to wonder if you had an oddball motor shaft size.

Drawcut....I have been running the Gears through the weekend printing quite a few parts for friends and they are working great. My extruder motor is now only getting warm instead of so hot I could not keep my finger on it. All in all it seems to be running quite a bit smoother than with the herringbone gear set...Thank again for putting these together.

agreed. PrintrBot should have spur gears. I will print a set for when my herringbone gears give out.

The PrintrBot uses an inappropriate, and possibly detrimental application of
double helical gear (Herringbone gears). When using double helical
gear the one cog must be free to float in the axial direction.
Otherwise they are over constrained and may lead to poor performance.
The extruder applica
tion as currently designed is better for spur

Also "Whereas spur gears are used for low speed applications and those
situations where noise control is not a problem, the use of helical
gears is indicated when the application involves high speeds, large
power transmission, or where noise aba
tement is important. The speed
is considered to be high when the pitch line velocity exceeds 25 m/s."
http://en.wikipedia.org/wiki/Helical_gear#Helicalhttp://en.wikipedia.org/wiki/H... "