I took a 9" grinder/sander with a wire cup on it and found a 3/4" tall "S" inside a 1" circle. This is on every crossmember I have brushed, any idea what it means?
Amazing what a course wire cup will clean at 5000 rpm smile
There are some areas that will be impossable to get inside the frame rails, Suggestions?


Thanks Brad

http://s320.photobucket.com/albums/nn343/brsdb3381/Tuesday_MY_56_Chevy/

56 3100 6 cyl