I mentioned before about needing to make a couple of cup washers for a Blake water pump. Well we ordered some 4mm leather so I got cracking: The body is 2" x 4" x 4" steel, bored out to 1 15/32", 7/16" deep. The brass plug is 1 5/32", approximately 8 mm less than the hole, to compensate for the thickness of the leather. There is a 10mm threaded hole in the bottom for the bolt to screw into. To use it, you cut out an over sized leather circle with a hole in the middle, soften it in water and tighten it between the plug and the hole. With it in the press, trim the excess leather and leave it a few days to harden. Then take it out and hopefully it will be a nice tight fit in the cylinder of the pump. That's the theory anyway, I'm yet to test it, fingers crossed. There's no reason to make it from thick steel, MDF would work just as well. I'll take some disassembled pictures tomorrow.