On our DE I used red oak blocks made from left-over flooring job. And, I inserted alum sleeves as bearings for the steel tubing of the rudder pedal assy. to rotate in. May not be necessary, but, at the time, I thought the sleeves would prevent any sticking from the oak swelling and provide longer lasting bearing surface. These blocks mount to a 1/4" thick plywood floorboard. This, to me, is the weak link of the assy. And, trying to keep the bearings blocks lined up to reduce binding was an effort, too.