Herringbone Gears for Robo3D R1

by SpectreGadget Apr 7, 2015
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this doesn't affect steps in EEPROM? having different gears

Not in this case, because the diameters and length of teeth are the same as the original. Of course, it never hurts to do a extruder calibration. :)

How do you calibrate extruder on the robo r1+?

At first, I tried to print them at the same time with supports and the both came out great looking, but the small one wouldn't fit.

When I tried to print the small one again, I realized on the v3, it had an extra line on the bottom making Cura print it a little above the build plate. I used the v2 small gear upside down with supports touching the build plate and it came out perfect and fit on the extruder without sanding, but I did use the handle of a screwdriver to get on snug.

The test part that I printed looks identical to the one printed with stock gears without calibration.

Excellent, thanks for sharing!

Comments deleted.

Here's some feedback and I'm still working on it. I'm installing these on the Robo R1 Plus which I got in Feb '16. LD Products ABS, Extruder 240C, Bed 100C, Disable fan for first 8 layers then 100% (it seems to need it on the small gear to keep the teeth clean but no fan for the large gear).

Small gear v3 was a tight fit and required a lot of filing to go on and is still a pretty tight fit.

Gears seem to mesh a little too tight and has more drag than the stock spur gears. It got better when I took a wire brush on the Dremel and brushed the ends up some. Drag is moderate now compared to the spur gears.

It's easy to overtighten the nut on the large gear as I think the new Robos come with less thread on the hobbed bolt and it's easy to try to get more locknut onto the threads. Based on the photo you posted, there isn't anywhere near that much thread and the cut for the hex nut on my spur gear is much deeper. Thru hole depth (the diameter of the hobbed bolt portion) on the spur gear measures 4mm so the nut sits much deeper than what you have here.

Thanks for the comments. Interesting about the tight meshing. I've printed two sets and not had that problem, but I have an R1. The print looks good!

After playing with it, it was a matter more of alignment than tight mesh...the stepper is not perfectly aligned with the extruder and I shimmed the motor to make it parallel and moved the small gear out a fuzz to line up the center of the teeth closer. Also took a small file to the teeth to smooth them out a bit and it fits pretty stinkin good and moves with little friction.

The hex nut needs to be deeper to engage more of the nylon threads...it appears your printer has a longer hobbed bolt by the photo. I tried downloading the SCAD files and the OpenCAD software in hopes to make that cut for the hex nut deeper...is it possible you could model the change in a different REV? On my R1 PLA +ABS the gear hub measures 14mm thick and the depth of the cut for the nut is 8mm. I can send a photo if you'd like.


Spectre, nice design! There are a few STL files listed here. Which ones should we be using for the Robo? I think there are two small gears listed here...although I think I'll wait to see how the newest rev with the .1mm smaller hole comes out for you.


Newest revision fits onto the Robo3D R1+ no problem

I just printed this out for my R1+, while it fit no problem, it wasn't a tight fit, I can easily remove it with my fingers. If it were maybe 0.1-0.2 mm smaller, it would squeeze right on!

Can't please anyone! Just kidding. I've tweaked it by about 0.15 smaller to make it a tight fight, which is good. I'm printing one now to see how it does.

I whipped up a test in solidworks, using a diameter 5.3mm and a distance of 4.65mm from flat to diameter, or 2mm from flat to center of hole. This print fit nice and snug. Are you able to save a .step file out of your program?

I'm glad it fit well. I adjusted it, but wasn't near the printer so took a shot at it based on when I had to file mine. Thanks for sharing!

The gears look great except the hole isn't large enough on the small gear. I am going to try to file it a bit.

I am on the Robo3D Plus. Will this makes any difference on my printouts?

I haven't seen a R1+ yet, so I'm not sure, but I don't think they changed the gearing.

Thanks for the reply. I think this will be my next mod. So am wondering, do I need to change my firmware settings if I were to fit this?

You shouldn't need to. I designed these to be the same diameter for both small and large gear, so extrusion rates should be the same.

I finally did print this out but yes the small gear do need a lot of filing. Took me lots of tries but finally I managed to made it slide onto the Stepper Motor shaft.

BUT now the large gear can't fit it. I guess my filing is off center causing the small gear to shift position for a tiny bit. I'll upload pictures to show the prints.

Did you put them on at the same time? Due to the angled teeth, I put the small one on the stepper, hold the large one against it, and then slide the bolt through. Then turn the large gear to get the nut screwed on and snug.

Yes that is what I did. Slide the small one first then try to aligned the large one. By doing that the hole of the large gear is way off to the right side of its shaft. I try to push the large gear in & slowly tightening it but I can see both of them are actually too close to each other.

I don't want to continue as I am scared I might damaged something in the process.

Printed out just fine, but the small gear is giving trouble on the fit (even with some filing).
Same double flat blade on the NEMA, but some kind of fraction of a fraction an inch too big.. lol

Since the big gear traps the smaller (via the lip) i can probably go ahead and open the small gear opening a bit. It's a bit tricky to get it right given the crude way that I did it in SCAD. :)

I know more about the surface of Jupiter than how to use Sketchup, but I'm printing one out now that I "opened up" a tiny bit.. Lol
It'll probably fly right off..