Thanks for all the help guys. Hanks idea of the plywood mount and GBHRPS idea of the stud finder
made it all come together. The stud finder is one that I've had for 43 years, my DW. She found me and today she pointed out two on a interior wall that I had not looked at. Hanks idea on the plywood will easly cover two studs and make mounting the swivel arm a breeze. Thanks again!
You guys Rock!
jim B