Originally Posted by
Grand Bois
You don't know it's impractical because you haven't tried it. Kelly Takeoffs or Retroshifts are not a better choice for a cheaper alternative to Kelly Takeoffs or Retroshifts. Some of us enjoy tinkering rather than just buying expensive parts and bolting them on. I'm sure lot of those expensive parts are the result of tinkering. Don't discourage tinkerers!
I'm not discouraging tinkerers but in this case the cure will probably be more expensive than using a commercially available product. BTW, remember Sun Tour's "Command Shift"? They mounted pretty much like the OP is describing but on suitably designed bosses.