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Why use a custom wrench? If you used a regular old nut you could tighten and loosen it with just standard bike tools that (nearly) everyone brings on (nearly) every ride. Also would it need some sort of tab on the far nut to stop it from rotating when you turn the Allen bolt?
Pretty cool though, I'd buy it if you could figure out a way to make a set for a tenner
Edit: further question, what's the reasoning behind the different thread pitches? To allow tightening/loosening through the differential screw mechanism using only the Allen key?
frankenbike-
Why use a custom wrench?
Because why not? It's a #tartmode product, so a custom tool that keeps the flank pressure low (compared with just making it a hexagon) is the least I can do :) Low flank pressure means the tool can be made from aluminium, saving weight in your tool roll.
In practice, the bolt would be Torx for similar reasons, but I couldn't be arsed to draw it
would it need some sort of tab on the far nut to stop it from rotating when you turn the Allen bolt?
No, you're only doing the M5 thread up finger tight. Normal Allen key skewer nuts aren't tabbed or held with a tool, friction alone allows them to stay put when you're tightening them.
Edit: further question, what's the reasoning behind the different thread pitches?
Only that M8×0.75 is a thread you already have on your bike. It doesn't have to be different from the 0.8mm pitch on the 5mm end for the skewer to work
I'd buy it if you could figure out a way to make a set for a tenner
If you could find your way to ordering 10000 sets, I can probably do them for a tenner each :)
gbj_tester
Snug it up using the M5 thread as per a normal Allen key skewer, then hold the bolt head stationary with the Allen key and tighten the splined nut on the same end with a custom wrench to drive the nut towards the dropout face on the M8×0.75 threads cut on the outside of the bolt head and the inside of the splined nut. It looks like a differential screw, and would work as one if you turned the bolt while holding both nuts stationary, but by cheating you can use the big 8mm thread to pull on the 5mm shank without simultaneously applying any torsional load to the bolt shank.