I modeled and created some mounts to use for my motorcycle pannie. I was able to find some scrap steel material for the project. I wanted the pannie to be removable and strong enough to support fully loaded pannie. The concept uses 10 M8 SHCS per side to connect the mounts to the racks on the bike.
I took the bike for an extended trip after completing the project and they worked perfectly. Making my own mounts was able to save me some money, but I would recommend making them out of aluminum in the future. A lot less machining time, lighter and they would not have to be coated to prevent corrosion. Steel was just the material I had laying around. These mounts are designed to work with 0.750" square tubing racks.