I use a 3/4 fine thread bolt that has a solid disc/washer welded along the shank. Slide the brake plate on, then a couple of stiff spacers then the nut done up firm. Once mounted in the chuck, you then need to shift things around to get the plate spinning with as little run out as possible. Make sure the two fixed anchor pins are straight and parallel to one another first or else the shoes will be hanging out too much. Mount the shoes with two split pins and put a 0.010" shim between each cam face and the pad on the shoe, this lifts each shoe just enough for clearance once you assemble it up. Then machine the linings down so the assembly just slide into it's mating drum not too loose or too tight. When you remove the shims and refit the brake arms plus the H 13 serrated washers, the arm should move about 8 to 10 mm at the end of the arm with the brake plate assembly put into its mating drum. make sure the shoes have a chamfer on each end to stop the brake from being too grabby. Use some grease on the cam and boss in the brake plate, perhaps a little on the fixed pivots not too much, as it is easy for grease to end up on the linings rendering that brake near useless. I usually scuff up the drum surface with emery tape for improved friction whenever I have them apart too. To straighten bent anchor pins use two steel rulers to see how far out they are, hold the pate in the vice, pins above the jaws, and I use two lengths of steel pipe with a bore of 1/2 inch, slip these over each pin and bend the pins apart with hand pressure. Works very well and very quick, keep using the rulers to check on your progress, most old plates have bent pins. Cheers..............Greg.
