It escapes me why this part needs to be threaded at all. It is hard to conceive of an application where a clearance hole drilled in the center and a roll pin cross drilled to fix the crank to the threaded shaft would not be good enough. It might also be more appropriate for the OP's skill level and equipment situation. If there is any slop in the clearance hole, then let's get the much vaunted JB Weld into this thread. (We should not pass up a chance to suggest JB Weld.) And I guess we, for completeness, should include McMaster-Carr which could undoubtedly supply the needed roll-pin as well as any drill bits, drill motors, and space-occupying epoxies should JB not be good enough.
Maybe eliminate the jb, drill a 19/32 hole and tap that with the tap in a cordless drill. No oil, no dr pepper, no wobble, no fuss. then cross holes and pin.