I believe I could make a lead platter with a bit of work, especially if I had one to build up from. IOW, take an existing 50# platter and add a layer of lead by creating a casting form that extends its perimeter and then truing it up on a milling machine. It may even be preferable to simply build up the edge inch or so and leave the inner dimensions. This would only work on the later models that used a higher speed motor and perimeter belt rather than riding the belt on the bearing subplatter which this version would obscure from access.
Re: the motor mount, I'm thinking the easy way would be to use 3" diameter PVC pipe, glue a hard plastic cap into the top with holes for the spindle and mounting bolts, screw another into the bottom with a hole for the wire, and fIll it with lead shot.
Re: the motor mount, I'm thinking the easy way would be to use 3" diameter PVC pipe, glue a hard plastic cap into the top with holes for the spindle and mounting bolts, screw another into the bottom with a hole for the wire, and fIll it with lead shot.