HP-18 Type Wing Spar Draw Bar
by Udo Rumpf
The fork has one time adjustable "contact" heads. The heads are 2 large socket head screws. A thread is cut into the 3/4" sq. tubing and the width is adjusted to allow the fork to slip over the spar. (between the round head rivets) The bolts are trimmed and welded permanently once the width dimension is set. The heads contact the vertical aluminum strip.
The shaped hook that hugs the link is aluminum. The drawing is to scale.