i just baught the same jig a few weeks ago, i know just what yer talking about, at one side of the vane on front or back, or both, the edge of the vane isnt sitting on the shaft tight, u will have to straighten the clamp out a bit to get it to sit just right, or be honest i have mine at more of an offset than its supposed to be, so that blazers dont even sit on the shaft exact, but it still works fine, and where it doesnt sit all theway down i just put a little glue over it after they done drien then wide it off with a cue tip, so that extra glue gets under the tiny edge, i have yet to see a problem with them, if i dont do this i cant really get much offset at all ( only supposed to be able to get 2 degrees anyways but i bet im gettin twice that )