After about 3 years of trying, I’ve finally managed to make a design for sets of all 3 calipers… which is (surprise surprise), a combination of existing designs
Which works quite well. I’d have preferred not to have moving parts, but I think this solution is better than having elastic, or something held in place with magnets (which could then get lost). Simpler is better… and the whole thing looks quite cool I think.
I’ve worked out the price to be $49 – which is doable… but I suspect the way I make postage free, wipes out any profit.
Sending a set of 3 costs an extra $20 in stamps… and these won’t be that different. As things stand, I’m basically making the cases a free giveaway with each set of calipers… and they’re already a “buy 2, get one free” deal.
I think I might need to make surface-post (which is pretty slow) free, but charge a % for airmail.