I bent up the rudder ribs using the previously built bend brake. 3/8" wide at the trailing edge and 3/4" wide at the leading edge with 1/4" high. Gussets are made from the same 6061-T6 0.020" aluminium. To get the correct gusset shape I folded cardboard over the joint, drawing the rivet positions. Then unfolded the cardboard and traced to the sheet aluminium before using the tin snips to cut the gusset out. To get the radius right for the 180 degree bend I wrapped the aluminium around a slightly smaller radiused piece of steel. This works well when allowing for the 'spring back' For the 3/8" diameter in this photo I went to the smaller 1/4" steel and on the 3/4" leading edge went to 5/8" steel. I have rounded off the sharp edges on all the gussets before lining up and marking each rivet hole. A piece of timber the width of the rib is slid in behind to stop the #30 drill bit from crushing the channel when drilling through.
