Another option (depending how much torque is involved): grind a slot in the end of one shaft and grind the end of the other shaft to form a lug which fits in the slot.
@More Coffee
The catalouge you showed there is really nice. But to be honest, not for a cheap toy.
However, I'm very glad to know where to find products like this for possible projects in the future
@alec_t
Thanks, I'll consider this. I do have a Black'n decker rt 650, so I should be able to make it.