by MtnDon » Tue Aug 16, 2016 9:50 pm
Two different things being talked about here. .....
Clutch head screws used to be used in automotive work and travel trailers. Those do use a special screwdriver and can be removed. Vintage Trailer sells the bits.
Today many cargo trailers used a special fastener for their interior plywood. They are not easily removed. They are used because the interior plywood is a part of the structure and if removed the trailer will self destruct as it is towed over the road. Removal of those fasteners, which do have a phillips head often involves some destruction. They will not unscrew. They spin if you try. Some folks rip the plywood off pulling the heads through, more or less. Others have used small hole saw cutters to cut a circular plug out of the plywood at each screw. Then reposition the plywood if reattaching the same plywood.
I removed most of ours by prying the screwout of the metal wall rib forcibly using vice grips and/or a prybay and a wood block. It tore a hole in the rib with each removal. Itgot the job done. The plywood was repositioned and resecured after insulation using self drilling metal screws.