Hey all, I have some Ford 40's drums I came across that will need turned. What is max ID for the drum, meaning when is it still usable V.S. when is there no life left? I've not been able to find and spec's anywhere on what a good/average ID should be for these. Thanks in advance!!! ~Ryan
Typically 12.060 is the max for safely turning '40 brake drums. However, lots of guys go to 12.090, like the aftermarket '39 Lincoln brake package sold by MT Brake product shown on the left below. I would stay with 12.060 in. The stock '40 drum is shown to the right.
The 12.090 on the drum shown means that specific drum was designed to be turned that much, not that it is safe to turn the standard drum that much. I have always heard 12.060 unless otherwise marked. Charlie Stephens