Once the three holes in the bracket spar interface are complete, the next step is plate nuts. The six most outboard brackets have plate nuts installed to receive mounting bolts inserted from the aft (inside) face of the spar. The most inboard bracket is the opposite – three plate nuts are installed on the aft face of the spare and the bolts are inserted from the bracket side. I only got two brackets done tonight, but I have the process down. For each #12 hole, doing them one at a time, I mount a old plate nut (same one I used for the wing spars I think) for drilling the rivet holes. I used a small scale to make sure it was straight on the flange and then I took it over to the drill press to drill each hole. Next up was using the caged countersink for the spar side so the bracket will sit flush. I clamped up two brackets end to end for countersinking the end holes – the countersink needs support on both sides or the hole to get a good symmetric countersink.
