1/2 hex shaft coupling

[thefro526]

Last year, we bought one of these: http://www.mcmaster.com/#2424k14/=qfauwg and ran a broach through it. I'm not entirely sure how well it will perform as a power transferring connection, but it connects two shafts just fine. Initially, we planned on running power through that coupling and then onto our climbing mechanism, but that never panned out, so instead, it just connected the two 'stub' shafts that our arm pivoted on.

In a pitch, I've also seen teams take a hex hub from AndyMark, drill two holes in it for set screws and use that to connect two shafts. Works just fine, but isn't 'pretty' fix unless you take the bolting surface off.