ExtruTim Drybox Respin

Update 11 FEB 2026:I have added a version of the base that accepts 5mm metal axles.   The holes are snug enough that the axles will stay in place with just friction, but if you use 4mmID tubing you can also  tap the ends for either #8 or M4.5 screws.  Button head or pan head should be fine, and use the shortest length you can source.    I recommend this version if you want to utilize the dual 250g spool feature.  The metal axles don't sag like the printed ones, and thus the tops of the spools don't touch.   I have left the printed axle version, because this works fine with 1kg or single 250g spools, and avoids having to source the metal tubing and screws.

Update 05 FEB 2026: I have added a gromet with plug and a plug for a silicone gromet.    The gromet may trigger OCD since the tether has to twist to allow printing without supports.  These both need 1/4"/6mm holes.  The TPU gromet is snug in a 1/4" hole, but may be over-tight in a 6mm hole, so you may have to waller it out a little if you live in an enlightened country.  These are the silicone gromets I used: https://a.co/d/0d758lSZ

One of the comments on Extrutim's drybox indicated that the rollers were too narrow for some rolls of a particular brand of filament.  This remix makes the container walls the limiting factor for spool width.    A comment on another drybox design requested accommodation for 250g filament spools.   The increased roller width allows TWO 250g spools to fit in the drybox.  

There is currently an issue with 250g spools:  The printed axles sag slightly allowing the upper rim of the spools to touch.   They still turn OK.   I have ordered some 5mm aluminum tube to use for axles, and will update this model if that works out.  If it doesn't work, I have in mind a design going back to the 5mm screws, but the rollers will be narrower and possibly larger. 

^^^see 11 Feb 2026 update! ^^^^^

You can use the 1kg rollers with a single 250g spool if you like, just use the front and middle axle mounting positions.

If you have sharp eyes you may note that one of the ears is broken in the single-spool photo.   This was an earlier design iteration that used open slots for the axles.   These were replaced by keyhole slots which make the ears much more robust.

Printing notes: 

All files in this remix print with no supports.

Print the rollers with random seam position, otherwise you will have a speed bump on your rollers.

Print the base/axels with aligned seams, otherwise the roller support ears ted to crack if when a seam lands on one of the edges.  Also printing with inner/outer wall order makes the base a little stronger and the layer lines are less prominent.

Assembly notes:  The 3 piece rollers wedge together nicely and need no glue.   

Update 05 FEB 2026: The axels might need some help from pliers to force the notches into the keyhole slots. Depending on how precise the print is, the fit of the axles may be over-tight.   One stroke with a serrated knife blade through the axle notches using modest pressure will ease the fit.  It doesn't take much, just enough to knock down the layer lines.

There are washers to space the spools on the 250g rollers.  The small washer goes on the flat side of the large washer.

If you are using the metal tube axle version, and want to secure the axles with screws, the easiest way to tap the axles is to chuck the axle in a drill motor, and run it onto a tap held stationary with a tap wrench.  4mm ID is well over the minor diameter for either #8 (24 or 32tpi) or M4.5 threads, so the shallow threads cut pretty easily.