This is a spool holder I designed out of necessity back in March, not long after I got my printer. I consider it to be the first 'real' part I made. Print two sets of parts for one complete spool holder. You will need FOUR common 608 bearings, a.k.a. 'skate bearings'.It uses standard bearings that most Makers probably already have a drawer full of and that makes the spool rotate super-smooth. It's also relatively fast-printing, and you can get away with printing it at as low a resolution as you'd like to make it go faster. (I'd recommend not skimping on infill though.) It should fit any spool, so long as the rim of the spool isn't thicker than the width of the bearing... And out of 8 different spool types I have, I haven't found one that didn't fit. (Even a mini spool wasn't small enough to bottom-out between the bearings.)Rafts: NoSupports: NoResolution: 0.25mm or largerInfill: Whatever, though the more solid the better.How it came about:I was putting my printer on 14-inch deep wire shelving, but it would only fit without the filament spools mounted on the back. I decided the thing to do would be to mount the spools on the shelf above, and run the filament down to the printer...so I'd need to make spool holders!NOTE: I replaced the version 3 files with version 4, which has a feature I thought was unnecessary-- an additional 1mm lip --and removed from my original design. (Without it, spools with very thin rims might be able to come off the bearing.) This version is now identical to the ones I've been using with my printer for almost six months now, and as it turns out the difference in print times was entirely negligible anyway.For one complete spool holder you need to print two sets of parts, and you will need four common 608 bearings.Print two each of PartA and PartB. Press-fit 608 bearings onto bosses on PartA. (Should be a tight fit.) Press-fit PartA and bearings to PartB. (Should also be a tight fit, might not get them apart again.) ???