As Sleepy said there is a 3/4" piece of pine in the corner but I can't recall if this will be of much use on the 835 Lance. I added the 3/4"piece to give me the support in the area that I wanted to mount the arm. The side panel is only 3/16" at best. Get the arm that you like first then you will better see where to mount it. I got mine at OSH of all places.