Great progress Ben!
Its funny to see little parts like this. In the power transmission industry we make a very similar coupling. However, its slightly larger and can handle a little more torque (11,000 ft/lbs / 15,000 nm) as well as up to a 7.25" shaft.
http://pt.rexnord.com/products/coupl...s/wrapflex.asp
Here is one of the smaller ones.
