Vertical stacking bracket for Prusa USS Drybox

This bracket clicks onto the top of a Prusa USS Drybox and allows dryboxes to be stacked upright vertically.

The dryboxes can be laid down and stack horizontally, but sometimes depending on space you can fit more in a cupboard if they are stacked vertically.

This bracket adds only a few millimetres to the overall height (as opposed to balancing them on top of each other without the bracket).

There is also a space on the front of the bracket to fit one of @Seemomster's 80x35mm sample cards so you can more clearly see what filament is inside the drybox.  The cards just slide in and out, and hopefully are held securely enough that they won't fall out unexpectedly!

To attach it to the drybox, place it on top of the drybox at an angle, with one side coming into contact first, then the other, and it should click into place.  When correctly fitted, the drybox can be lifted up by the bracket and it will not come loose (although this may not be a great idea to do regularly, as then the two tabs on the top of the drybox are taking the full weight of the drybox and spool so they may eventually break from strain).

To remove it, pull one side up from the edge.  If it does not come away easily, try the other side.  Typically the side without the card holder is the easiest to pull up to remove.

During testing I found it works fine with only 5% fill, however it is subject to damage if dropped while attached to a drybox, due to the thin walls having little support.  Printing at the default 15% fill is probably overkill but it does produce a much more robust object that can take more punishment.  I used the gyroid fill pattern at both 5% and 15% with good results.

When printed on its side (should be the default orientation when importing the STL) there is only one overhang (the hole in the middle) and this is not structural so it should print without issue.  If the hole doesn't print neatly you can tidy it up after.  I found it printed perfectly with PLA and needed a little clean up after printing with white PETG but it was fine with black PETG.  It can only be printed in this one orientation without overhangs so don't try it in another orientation or you'll get poor results.

The hole in the middle is to keep the added vertical height to a minimum.  Sealing the hole will result in an extra millimetre or so added to the overall height of two stacked dryboxes, and since the purpose of this bracket is to fit them into tight spaces, the bracket should take up as little space as possible.

Stacking three, maybe four tall is about the practical limit as the drybox feet are uneven and so they wobble when placed on a flat surface, making the vertical stack unsteady.  They should be stacked in such a way that it is difficult for them to topple over (e.g. inside a cupboard).