Assemble the Bell/Hiller mixer with 2 ea 3X7X3 bearings, a “special” 3X12mm
bolt w 6mm shank, brass washer as a spacer, and the blade grip pitch arm.
Install the assembled bell/hiller mixer by threading the bolt into the middle hole
on the pitch arm (recommended). This hole gives a 0 Delta offset, the other two
holes give a positive or negative delta offset for those so inclined to experiment.
Set the tension on the bearings, tightening the bolt to give a free spinning yet
slop free movement, then tighten the nut on the back. Check the movement and
readjust as necessary. Repeat for the second pitch arm.