So I got an ampeg svt-810pro on craiglist. It's pretty beat up and someone had already replaced the wood under the casters, but there were still two problems: 1. The base of the casters stuck out from the back of the unit and would catch on any steps or door jams. This made moving the fridge near impossible. So my first project was just to install some aluminum strips down the back. That's done and they worked. but 2. the casters themselves were in really bad shape and a wheel broke on me after a gig last week. Since I was going to replace the casters (which were 3 inch) with 4 inch, I thought I'd also replace the wood underneath them, since the previous repair was such a sloppy job. I'm no pro, but this was just screws stuck in randomly, and I'm also not sure they got the fit of the wood base correct relative the sides, front and back. Here are some pics: https://www.dropbox.com/sh/9vrttc9ksoh3ygy/JegLNY57A1/ampeg 810 repair So, recommendations would be helpful. I have plywood, circular saw, drill, countersink and some 4 inch, non-turning casters from the hardware store. A. I'd like to know how the replacement piece should fit into the cavity -- does this replacement piece of wood "cover" over the bottom, back, and sides or does it sit flush with the existing edges? B. And what would be the recommended way to attach this to the existing would for it to be solid. Thanks!