Where to find Herringbone gears for M90?

I printed I3 Herringbone gears but they are too big for M90 Wades. Where can I find suitable pair?

Or what I need to change in i3 config to make it?
I tried to change number of teeth but how to calculate corresponding distance?
It seems that big gear need to be 39-40 teeth

Edited 3 time(s). Last edit at 03/02/2014 05:21PM by karabas.

I tweaked these to make the gears I am currently using. The small gear has very little clearance between the gear and the motor so you might want to file off ~0.5mm unless you know how to fix the scad. The set is 39:11 - same as the standard mendel90 set.

Thank you!
I will try it.

Have you printed these yet?
I think I'd like to give them a go too....

(anyone willing to convert these to STL? - I don't have open scad installed)

---

--------------------------------------------------------
Custom all metal CoreXY
- Duet 2 Wifi w/ PanelDue 7i
- 330mm x 360mm x 500mm
- 750w Silicon heater

Custom Mendel90
(Backup printer - Old reliable!) - Sold

Hi,

Quote
Mogal
(anyone willing to convert these to STL? - I don't have open scad installed)

here you go:

Herringbone_gears_hi-res.zip

---

MfG / Regards

Stefan

---

Blog / Gallery / Wiki / Mendel90 kit since Sep 2013 from Nophead / Original Prusa I3 MK3 since Feb 2018 /
OpenScad Workshop: Kursdateien
Octoprint Patron since April 2016

Hi,

has anybody tried to mount these gears already?

I tried it yesterday - with no luck. It seems that the head of the hobbed bolt does not sit deep enough in the cavity. The "hobbes" aren't at the place where they should be to grab the filament. Would heating up the bold help here to press it deeper into? What else could be wrong?

---

MfG / Regards

Stefan

---

Blog / Gallery / Wiki / Mendel90 kit since Sep 2013 from Nophead / Original Prusa I3 MK3 since Feb 2018 /
OpenScad Workshop: Kursdateien
Octoprint Patron since April 2016

When I made my large gear I had some issues with the M8 head cavity. One was to get the corners sharp enough so the bolt head did not catch on them. The other was to get the perfect snug fit across the flats so the bolt head was firmly held.

(If your bolt aligns with the standard nophead issued extruder block - spacer - large gear, it should (if seated correctly) align with the above herringbone gear as well. I am assuming this is the case and that you're not running some other customizations that would change the offset of the hobbed portion.)

In my case a calibration of the extruded width solved both issues - I printed mine in PLA 0.2mm thick / 0.5mm wide profile. The corners of the bolt head did catch a little but not enough to be a problem after some minor cleanup with a sharp blade. Following noheads formulas in the build instructions I got the right distance across the bolt head flats right automatically - I'm using Skeinforge.

In case I had had more serious problems with the corner sharpness I would have looked closer at Skeinforge-Stretch (I hope I'm not mixing it up, anyway the module that compensates for hole diameter) to make the bends sharper. Failing that I'd look at adding a feature in the cad model to make small cutouts in the corners - which would imply modifying the scad model.

In case of issues with the distance between the flats - and your slicer makes too narrow internal openings - I'd simply tweak the scad parameter driving the bolt head width. It's towards the end of the "WadeL_double_helix" module:

union () {
			translate([0,0,10])rotate([180,0,0])cylinder(r=4,h=20,$fn=circle_facets*10);
			translate ([0,0,(hub_height/2) + hub_base + 6]) rotate ([0,0,30]) hexagon(height=12.8, depth=hub_height);
		}

...hope that helps...

Hi svanteg,

I'm using the kit version from nophead with no customizations. And I'm using skeinforge with the recent profiles provided from RyanMark here. I printed PLA with the 0.2 mm profile.

Do you think I should print the big gear again with your changes? Isn't there any way to use my already printed gear? My corners are sharp and I habe a very snug fit across the flats. It feels like too snug. Heating up the bolt should do the trick?

---

MfG / Regards

Stefan

---

Blog / Gallery / Wiki / Mendel90 kit since Sep 2013 from Nophead / Original Prusa I3 MK3 since Feb 2018 /
OpenScad Workshop: Kursdateien
Octoprint Patron since April 2016

If you're ok with printing a new one - should heat-fitting the bolt warp the gear you have - then just go for it. If it works it works. If it doesn't you print a new one. Depending on how much you heat it, you might want to be careful not to warp the bolt - that you cannot print a spare for...

Personally I wanted to learn how to get a precise print so I ended up printing about four large gears before I settled on the one I have now...so I would tweak either the calibration, slicer params or the scad model to get a gear I like. But that's just me.

Since it's PLA I'd be a bit conscious about too tight a fit - as it can generate stress fractures. So I agree with what your trying to do.

Edited 1 time(s). Last edit at 04/01/2014 05:52PM by svanteg.