Pulley for Geeetech Prusa i3 B+C Idler Belt Tensioner

by TimeWaster, published

Pulley for Geeetech Prusa i3 B+C Idler Belt Tensioner by TimeWaster Nov 6, 2015


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I bought a cheap China Geeetech Prusa i3 printer, and the idlers just came with two 624ZZ ball bearings, so the belt didn't have any guidance and rubbed against the sharp metal all the time.

This pulley solves that, it is made to fit over two 624 ball bearings and guide the 6mm wide belt without destroying it.

Apparently this is compatible with the Geeetech Delta Rostock G2 and G2S.

Please note, a standard tolerance of 0.2mm is set to compensate for the overprint of the Geeetech printers. if you want to print it on another printer or it still doesn't fit you can change the tolerance in the SCAD code (In the Customizer App or in OpenSCAD directly).

Please DO NOT scale the .stl file, this would create wrong outer dimensions, please use the customizer.

Let me know if you have problems or successfully printed it!

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I just used this to replace a seized Y axis pulley on my printer, works a treat! My i3 Pro B shipped with aluminium pulleys, but it looks like the bearings in them were just pounded in with a hammer, so no surprise that it failed. I replaced the seized pulley with two 624ZZ's I had around and was able to print your replacement part. I can confirm that this pulley works perfectly on the Pro B that ships with aluminium pulleys. Thanks for the part!

A very much needed upgrade on my printer.
I had to reduce the width of the track in the pulley by 1 mm. If I printed and used it with it's original fit, the pulley would occasionally get rub on the U-bracket and in worst case the printed would loose some steps on the Y-axis.
Thanks for your design!

If someone needs a smaller Version, i remixed it for MR74ZZ ball bearings: https://www.thingiverse.com/thing:1818674
And small without ballbearings: https://www.thingiverse.com/thing:1775944

Thank you very much for the .scad-file!

Idler/Pulley Replacement with MR74ZZ ball bearings for Geeetech Prusa i3 X
by datdiy
Idler/Pulley Replacement for Geeetech Prusa i3 X
by datdiy

Wow I was about to draw this up myself. Last time I checked Thingiverse was before you made this. Good thing I checked, you saved me some work. Thanks dude.

Great addition that works also on the Geeetech Delta Rostock G2 and G2S.

Thanks for this thing, wanted to make it myself but then i found this :)

Printed it, maybe my printer isn't calibrated that well, but it was little bit off, just measured and rescaled it in slicer!

Gonna print 2 of them, mostly for the x-axis not so much in for y-axis, but it will look nice and little less destruction of the belt :D

BTW, You can click on "Open in Customizer" to set a tolerance for the inner diameter to adapt to your printer.

Maybe i should set the .stl to a standard tolerance of 0.2...

Can you tell what printer you have and how much your print was too big?

It wasn't to big, but to small :) Bearings are 130mm and i only had 125mm so offset of 3,84615%, so schaling it by that percentage worked great.

I have a Geeetech Prusa i3 with some modifications, dont know the exact settings i used, but these are in the gcode:
; perimeters extrusion width = 0.35mm
; infill extrusion width = 0.52mm
; solid infill extrusion width = 0.52mm
; top infill extrusion width = 0.52mm

yes, so setting 0.25 in the "Tolerance Xy Axis" setting in "Customizer" would have been a perfect print.

i think i will use that as a standard since this is for one specific printer and all people should then get the same results.

thanx for your infos!

i just did, if you download the .stl file again and print it it should fit perfectly.

Hi creator,

thanks for your design sharing !
I got also same issue with my geeetech so you're part will help me...

Before printing, I would like to understand the meaning of tolerances to change in Customizer : your explanation isn't so clear ^^

thx for your help !

Hi Antoine,

depending on your printer setting and how much plastic the extruder is pressing out it can happen that a wall is printed thicker than specified by the .stl or .scad file.

If this is the case the ball bearings will not fit into the print, so i added a tolerance parameter to the .scad file where you can specify how much more space (bigger diameter on the inside of the pulley) the design should leave to compensate for the effect.

If you are unsure just print it as is, and when the ball bearings don't fit set a value of 0.2 for the xy axis and try again.