Maybe a cure for Mike Miller  ? Some transmission gear from an RC car...

Maybe a cure for @Mike_Miller ?
Some transmission gear from an RC car… I’ll try first and give you my source if it works.


Looking good…
Google Photos

I used the same one, but make sure that you use some sort of loctite or something on the set screw. Before I did, I had a few prints get ruined because of the set screw loosening in the soft brass. I’ve since moved to a mk8 hobbed pulley.

I’ll follow your tips. Thanks.

Please share the source for this gear. :slight_smile:

Michael nice found I soon try presta valve to shredder really cheap hope diameter are right but I want undestand why Mike break coil…I just take lot of coil for test

As a cyclist I should have remember that!!! Good idea… and nice thing you’re going for more research!

@Neil_MacDonald Look for “rc metal pinion shaft” at your local rc shop or in the internet. Internal diameter may have to be drilled for 5 mm diam. :slight_smile:

You could also try this one (already reported in another thread):

You’ll probably need a modification to adapt to this diameter. let me know on Thingiverse and I’ll upload the modified version.

Why do you guys work so hard to avoid using normal hobbed bolts?
I thought everyone moved away from gears and knurled bolts a while ago as they were found to be worse?
The best I’ve seen yet is the dual interlocked gear bolt that bondtech produces, if those were available at a price that everyone could afford it would be amazing.

@Oystein_Krog … mainly because it’s made to work with the #Saintflint. We need to have something that’s directly onto the stepper shaft. Another solution would be to grind the stepper shaft. Bold but feasible.
And I think the reason why the bolt are a good approach is what makes the #saintflint such an interesting solution: the small diameter.
If you combine this with a very hard material (but brittle), you’ve got yourself a very small and capable piece or extruder (especially on NEMA 14).

Hmm ok, but I still don’t understand why you can’t just use the the MK8 gear?
Edit: you can get an MK8 drive gear for less than a dollar w/free shipping…
I think the “loop” approach is very interesting and worth exploring, but it seems to me that the obsession with using flint etc. is not worth it.
Having a NEMA14 direct extruder is certainly something to strive for.

@Neil_MacDonald My bad for the erroneous source previously cited. From the benchmark I’ve just referenced, it’s a piece from RC boats:
“This gear was originally supplied with the MDF Sumpod; my first 3d printer. It’s usually called a Plain Insert Coupling, used for connecting universal joints to motor shafts in model boats. A quick google search “plain insert joint” found a number of suppliers with prices around GBP 2.00 (USD 2.64). Similar to the Plain Insert Couplings, a range are also sold under the brand Raboesch Couplings. The prices for the range are slightly more, GBP 2.26 (USD 2.97), and sold by Boots Industries as a drive gear for CAD 14.99; so shop around. Plain Insert Couplings and Raboesch Couplings look very similar but can’t tell how closely matched the teeth are without having both types in hand.”

@Oystein_Krog If you have an MK8, you may just use it with a special version I’ve did in the past:

Simple re use or find more common item for no wait shipping.

Thanks for the info! Much appreciated! :slight_smile:

@Oystein_Krog My experiences with extruders:
Wades - Worked great-ish, then fell down as the hobbed bolt wore out…bad luck in fabbing my own

BondTech - excellent experience in every way but price. Currently $90-$120 which is incompatible with people that would even consider cast-off flint-wheels. :smiley:

Printrbot Beta Gears - Factor provided printable housing not compatible with Bowden, the two ‘aftermarket’ solutions were unsustainable for more than a day at a time due to deformation.

Saintflint - poor experiences with flint destruction, excellent experiences with 17 tooth, hardened steel gear from RC store. In use for 1 week with zero extrusion failures.

I think that sets Saintflint apart is that the geared options need absolute precision to perform, and or extreme forces to cram the filament against bearing and textured device…the loads on Saint Flint are all relatively low, and the model prints successfully on printers that may not be 100% dialed in. On IGenUS, I have to scale to 106% any part that has inner diameters that are critical. I didn’t scale up the extruder, and the only mode needed to get the flint version working with my gear was a little dremel-work.