Still unable to insert the gear mount bolts through the bulkhead and spar into the gear mount steel plates. Finally stripped out the entire mount and re-examined the spar/bulkhead for issues. After determining that the forward side of the bulkhead plate was either slightly misaligned or the holes in the bottom were too small, one hole was reamed to 1/4" to accomodate the AN4 bolt. Very slight crescent of space results on one side of bolt but the result is a good straight and clean hole aligned with the aft side of the bulkhead and the spar.
Pic #3 shows the end of the ream unable to pass through the forward side, and an AN4 bolt. After slight clean-up with a deburring tool, the reamer was able to be pulled through to true up the plate holes. Bolts still have a secure fit in the holes but can now be inserted.
Need to re-install the gear mount and also review alignment of those matching bottom holes. Other holes in the sides (vertical) and top of the mount were already able to fit, some with guide pins to assist alignment.
