This is an adjustable print-in-place spool for filament samples. No assembly needed, just remove from build plate, snap off the built-in supports and you're good to go.
How to use:
Adjust the arms inwards until you can fit the sample roll onto the spool. If needed, press the thumb tab on the spring mechanism while moving the arms.
Fit the sample roll onto the spool and move the arms outward until the sample sits firmly in the spool. Secure the end in one of the holes.
IMPORTANT: Don't print the "without built-in supports"-version unless you know why. More info below.
EDIT: Added LARGE and HUGE versions upon request. The LARGE can take twice the filament of the standard, the HUGE 4 x standard. I have not printed nor tested these, so I don't know if they work. If you print these bigger versions, please report back and tell me how it turned out!
Note that even the HUGE version isn't designed to be compatible with the MasterSpool system, but for filament samples up to a few hundred grams.
Please post a Make if you make this!
I designed this with PLA in mind. PETG would probably work too, but the mechanism might be a bit looser due to the flexibility of PETG.
The tolerances should be no problem for a well calibrated printer. Just make sure to watch the first layer to insure all the perimeters around the moving parts are intact with no blobs or such. Abort the print and start over if you get problems with the first layer, as this may impact functionality.
If you're unsure if you printer can manage tolernaces of 0.25 mm, print the included TEST PIECE first to make sure the moving parts move.
EDIT: I've been getting reports of people having problems with the hinges fusing together. I'll try to upload a version with larger tolerances.
Remove the supports using a pair of pliers, they should come off easily.
I print this with 0.20 mm layers, 2 perimeters and 15 % gyroid infill. This keeps the weight around 50 grams. You can of course print it stronger if you like, but it seems to hold up just fine.
The built-in supports in the "forks" is a single layer with a standard 0.4 nozzle. If your nozzle or other settings prevents you from slicing it with the supports, feel free to experiment with the "without built-in supports" version. Just be sure no supports are generated in the gaps between moving parts.