Bag Hook for Aluminum Crutches (Canada - Guardian brand)

Hi all!

With a fresh leg injury, I grew tired of scooting around in an office chair any time I wanted to carry something around. So here is my version of a strong bag hook for crutches. These are for  my “under armpit” style of crutch – most designs I came across are for the forearm support style of crutches.

NON-PRINTED MATERIALS REQUIRED:
- 2x M4x30mm bolts (longer than 30mm fine, 25mm might work but untested)
- 2x M4 washers
- 2x M4 nut (nylon locknut ideal if you have on-hand)

I printed this in Sunlu Black PETG; PETG recommended. It is a little more flexible for fitting the hook to the pegs, but still very rigid in testing. If you only have PLA, that's probably fine, just keep an eye out for the hooks sagging if loaded hard for a long time.

The system requires to you print 2x pegs and 1x hook. The pegs have a curved end that mates with the aluminum frame snugly. Use a long M4 bolt (I only had 40mm long ones, but 30mm should work and look nicer) with a nut to fasten it – there is a 7mm deep recess for the M4 nut. I used nylon locknuts because I had them on hand and though it would be nice to not have these loosen, so you may want to use Loctite if you're using regular nuts.

The hook should be printed on its side for stength, and the pegs should be printed hex hole down (in that orientation, layers will be reinforced with the M4 bolt). This orientation is given in the master print file (OrcaSlicer):

Use tree supports for all parts – it is not visible, but the hex holes in the pegs are supported. Printed on a Bambu A1 mini, 0.4mm nozzle. Printed with 0.2mm layer, strength profile (~5-6 walls, 30% infill). Print took ~4.5hrs total.

My particular crutches use ~19.0mm aluminum tubes that are about 100.0mm apart. I reckon this is probably pretty standard. If you have a smaller or larger separation, you should be able to stretch the hook model in the slicer accordingly to fit the pegs. If the tubes of the crutch are a significantly larger or smaller diameter, the pegs might not fit as well, and this may be hard to fix directly in the slicer. If you have an issue in either case that you can't fix yourself, just contact me and I'll happily fix the model for your use case.

The hook model is a remix of a bag hook that I thought was pretty well designed (Mejlholm; https://makerworld.com/en/models/1147927-crutch-hook#profileId-1151610). However, the original version was designed to go over the rubber/silicone handle. Not only did it not fit my model, hard plastic on the hands would not be comfy. The part on this one that braces against the frame is also very long, and it makes the hook unusable with my peg idea unless the crutch handle close to the top, so I shortened the brace a little.

Pegs are entirely original. Hook modified to have a shorter arm (length of original is cumbersome, and was more than sufficiently strong), and a round clearance for the nut head that fastens the pegs.