Universal Spool Hub 51-55mm

This ball bearing spool hub sit on a 5/16 inch metal hex bolts, at least 4 inches long. This one is universally sized and the sides are slightly slanted so it can fit hubs from 51-55 mmi n diameter, which matches many widths of popular hubs such as Polymaker, Bambu, Inland, Sunlu, etc.

Fits the original Prusa MMU3 spool bearings (22mm outer diameter, 7mm thick and an 8mm center hole.

Print instructions:

• .25mm structural settings

• Use PETG

• 3 perimeter walls

• 25% infill

• Organic supports (easier to remove) 

4 inch long 5/16 inch metal bolt goes through a half inch thick wooden board (drill a 5/16 hole). On the other side of the board in this order use:

1. 5/16 inch metal washer

2. 5/16 metal nut

3. printed spoolhub with bearing pushed in with bearing side facing the nut above

4. spool

5. printed spoolhub with bearing pushed in with bearing side facing the end of the bolt

6. 5/16 metal nut

I use these in my buffer and spool system for the MMU3 where you can get the PTFE PC4-M10 Bracket you see above the spools, both left and right oriented. 

Changes:

• Using Prusa bearings, created a spool center hub around them that is free rolling and adjustable width along a rod, and fits sizes 51-55mm of hub diameters.