With the outside clamp gusset roughed out its time to gusset the inside clamp. I'm going to use the flat on the inside of the frame rail to help lock the bracket in place when the clamps are tightened. This requires the gusset to transition from round at one end to flat at the other. I'll make the gusset from 3 piece's of aluminum, fitting and welding each piece as I go. First I cut out a small piece of aluminum 10mm wide, then I ground the edge of the welding table to match the inside radius of the clamp. I then clamped the 10 mm work piece to the table over hanging the ground edge, heated it up and bend it over the edge of the table. Next I milled a small piece of aluminum to match the width of the inside of the clamp and ground the edge's to the radius ( I made a tool or a die.) Then I clamped the tool to the welding table and clamped the 10 mm work piece to the tool heated it up and bent the other end over the tool. A little fitting and trimming and I have my first of three piece's done.