Spool Hole Reduction for original PRUSA i3 Printer

by Karlosek Jul 23, 2015
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Yes, you did post the SCAD, but, I have been using another CAD program so SCAD is yet another "mountain" I have to climb.

Another thing I like about your design is that changing spools is pretty easy. You see other designs where reducer hubs are used on threaded rods with nuts and it would take more time to change out spools. Time may not be a big factor, but, I understand that recent s/w changes now allow for multiple filament colors during a run. I haven't yet had a need for multiple colors. If you were to use multiple colors, it would seem more efficient to simply "bank" the colors before you start. Then, all you would have to do is load and unload filaments when required.

I think I would just make your reducing hubs for each reel and run the reels together on a dowel. Of course, we'd need a new design for the end mounts that attach to the frame.


Thanks for designing this and sharing it! I had just finished putting my Prusa MK2 together and was ready to print when I saw the "flaky" way they held the spool. I guess it probably worked but I was afraid the spool might fall and damage the bed.

I also have a Lulzbot TAZ5 printer so I printed this out. I printed at 20% fill since this was just a "test". I found the diameter too small for the Gizmo Dorks filament reels I mostly use. So, I scaled your design up to 110%. It could probably be scaled up more, but, I was afraid I'd then have trouble getting it out of the reel. Also, I found that at 20% infill, the "fingers" broke off quite easily. So, for the final prints I just set the infill to 100%.

I think I may still look for, or design, a spool holder that uses some kind of "through" rod to make changing spools even easily. But, for now, your design enabled me to safely get started with the Prusa!


Hi Garry. Thank you for your comment. What you write about is exactly what happened to me. Spool fell down and crushed the glas on hetated bed.
I visited Prusa shop in Prague and saw them using no reductions for their printers at all. But still.. I think this is much safer way to hold the spool.
I thought I uploaded the open scad file to allow easy adjustments.
Thanks for your kind words.

Fantastic. Glad to see someone sharing parts for the awesome Original Prusa i3.

I've remixed a double sided spool holder to allow for more than one spool to be mounted on the frame. Just checking that it's okay to share before I upload.

Thanks for this thing.

Thank you for kind words!

You sure can upload your remix. No Problem.