Shunt, There's a picture above. Do you need any more measurements? It's a piece of 3/4 angle iron trimmed and folded. Real simple to make. Trim half the angle off as shown and then fold the end at a 90. Mount the switch as close to the corner as possible. Mine looks a little rough but I only spent an hour on it. I made it simple for those who don't have a lot of time for fabrication. I made it cheap for those on a budget. I picked durable parts for those that want to get it done and not have to worry about tweaking it all the time. It should last a long time because it's not subject to engine heat or the elements.
