Quote:
Originally Posted by Richard Lorenz
I mad some measurements that confirm what has been said above. The new cast iron drums measure 10.97 inches inside. This means that the inside diameter must be reduced 0.03 inches to reach the original Model A size of 11.000 inches.
I also measured parking brake diameters. The new cast iron diameter measurement is 9.65 inches. I measured an old steel drum that looked like there was essentially no wear on the parking brake drum surface. It was microscopically smaller. This means that one should not turn down the cast iron brake drum part any more than necessary to clean up all the way around. I would not go any deeper than this bare minimum because it would weaken the drum.
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Took my drums to a local Machinist! He used is electronic caliper and came up with the same you did, 10.97! One suggestion he made, since I had the hubs swaged into new drums, was to take them to the auto shop and have them put on the drum turning tool and assure the drum was centered on the hub properly, by doing a turn to assure true hub drum centering. I will do that today.