Hey! This thing is still a Work in Progress. Files, instructions, and other stuff might change!

MasterSpool Micro for small print beds V2

by Hormonfisch Mar 2, 2018
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I like your approach to the Masterspool. I can imagine two possible optimizations for this design.

1) It would be nice to clamp the starting end in the middle of the spool.
2) It would also be nice, to have the sticker attached to the spool. Label size is 29x90mm.

This is not a request to get it done, just to share the idea. ;-)

I'm glad you like the design and thanks for the critizism.

1) You can clamp down the end of the spool while screwing together the fork. I added a cutout, which works well for me so far. Did you have another idea?
2) I thought about this as well, but there's just so little room, and I wanted to keep the size of each part below 100x100mm. Perhaps I'll add an additionary part. Right now i solved this problem for me in a different way. On the photos you can barely see that I added two disks of clear foil to each side of the spool onto which i later attached the sticker. They also reduce the risk of entangling the filament.

Thanks for your response. I didn't notice the cutout. I will have a closer look ;-)

Hi! I was thinking about designing something like this, so I'm glad you already did :-)

I'm gonna give this a print tomorrow, then order some new PLA. One of the things I was thinking about was the ability to add some 608 bearings so that one can mount them cleanly on a 8mm rod. Any chance of sharing the CAD files/adding such an option? :D

Hi! I don't really like incorporating the bearing into the spools itself. It would spin too easily, and so the risk of entangling the filament will be way higher, especially for a spool with separated forks like this one. Instead I use the spool with this spool holder:
By tightening some nuts in the M8 rod you can increase the friction.
If you want to add the bearings anyways, here are the files:

Quick Change Universal Spool Holder

Nice! I'll give that spool holder a go, thanks for the feedback!

I like the basic concept but I don't get the choice of how it comes together, problem with this design is that you have to completely take it apart to swap filament on the spool, while the regular master spool (which my 200^3 original i3 bed) can't print splits into 2 halves for easy filament swapping.

Pondering ways to replicate that functionality on a smaller bed and hopefully less filament.

Edit: nvm, I get it, unscrew the 6 screws and the filament comes free, I guess you could add 3 zipties or velcro straps or paracord to bind the spool before taking it of the roll.

Taken a look at the models and the 3.4mm hole for m3 bolts is a bit... big, I mean it will probably work fine but the threaded section of an m3 bolt is 2.8mm so 3mm is all you need really, can do 3.2 for s&g. 25um between the fork and the slot in the center seems a bit.. tight, though dooable I guess, at worst can just give it some licks of sandpaper. The diameter of the inside of the 3 forks seems to match 102mm exactly, which is what the master spool uses, adjusted the holes down to 3mm and printing atm, I already have a coil of refill from dasfilament to try with it.

Thanks for the critizism. I don't reaaaaally like the use of 6 screws either, but it was a compromise i was willing to take.
I wanted to have:
-a sturdy spool
-the parts to be as small as possible and
-I didn't want to print any vertical pillars, to avoid having problems with layer adhesion.
If you've got ideas for improvement, i would really like to hear them

I just got my refill spool and it fits pretty well.
(btw. 3.4mm is the standard diameter of a clearance hole for a M3 bolt)

Just finished printing one: https://i.imgur.com/9PwK13L.jpg (I'm all out of 20mm bolts, just 30+ and 15- grr) and yeah it works, the assembly is a tad fiddly, my idea was buy a lot of masterspool refills and keep using one-two spools for all of them but unscrewing 6 screws would make that properly tedious. I reduced the m3 holes and nut holes 95% to 3.2mm and 6.x for the nuts, I have to melt in the nuts with a soldering iron after doing that but I prefer that because then they're kept in place on their own so to speak, m3 goes through 3.2mm nicely for me. Only part I can't say works for me is the 2mm~ hole for the filament end in middle, it's obstructed by the spool of filament for me and not accessible, I drilled a 2.5mm hole in one of the forks just past the hub clamp instead: https://i.imgur.com/bv4eqbq.png

Only idea so far I have for something easier to swap spools on that can fit on a smaller bed is something like this: https://i.imgur.com/oFLQqX2.png a 102x102x70~mm hub with dove-tailed spokes that you can also screw in for extra confidence (but the idea would be to make the screws optional) still working on that design though, think I have to make the dovetails wider because the sunk m3 head doesn't really fit. The hub is mostly hollow and meant to be printed in low infill btw.