In my main work shop I have a 4ft guillotine. It gets used but very infrequently and is/was being used as a shelf for other to hand bits. As space is tight I thought of adapting it as a workbench by using the sheet metal support extensions bolted to it as the base for the top. I turned them over(they are bolted to the main unit) and made a top support structure using 30x50mm box lengths(3 off). The outer box had to have end rectangles welded to it to ensure it did not drop off the end( the extensions when turned over area U channel) and further cut box sections joined the three together so they ended up a snug fit in all directions. The sheet was cut and shaped (1mm galvanised) and Araldited to the support carriage. Works well and it is removed easily.