Another Cast Iron Brake Question

[Bill T]

I am replaceing all 4 brake drums with new plasmeter cast iron drums with correct new lugs to attach them to original hubs.

The instructions that came with the drums say to put the new hubs on the original hubs and swedge the lugs tight. Then take the drums to a brake shop and have them true up the brake surfaces on a brake lathe. the new cast iron drums will require turning after pressing in the hub lug bolts.

I can see how the fronts will chuck into the brake lath, but, how do I chuck the rear drums with hubs mounted into the lath and turn them straight. Brake lathes I have seen have chucked the hubs betwee two cones that keep them straight and centered. The model A rear hub is too narrow to accept and fixture that I have seen. What am I missing?

Thank you, Bill T