Brief Description: Prepare Battery Box for Installation
Cut two 0.080" x 1" x 6" backing plates, laying out three 1/4" mounting holes with nutplates to spread the weight of the battery across the two plates to the firewall. Drilled six matching through holes in the firewall, a bit oversize to allow space for bolt alignment. Holes in the SST firewall were most easily drilled with a step drill. Step drill was also used on the cockpit side to deburr the holes. Test fit mounting plates to firewall to mark and drill locating holes for a pair of flush pulled rivets in each backing plate to secure the backing plate to the firewall. Firewall rivet holes drilled and dimpled. Backing plates rivited to firewall. Test fit battery box. AN4-5A bolts a little longer than required.
