Technical Modding Bolling drums for use with original 1941 Lincoln brakes

I ordered a set of 4 repop Bolling Brothers Lincoln drums from Thompson's Garage. Can't say enough good about both the service I received from Steve at Thompson's as well as the quality of the drums. I am running these against actual 1941 Lincoln brakes that have the extra splash ring on the plate.
https://www.jalopyjournal.com/forum/threads/1950s-tube-frame-sports-car.993579/
Going into this I knew I might have to modify the drums slightly. Maybe others considering this combination will find this helpful. It will probably be the same thing you'd have to do with Speedway's drums but I can't say for sure.
Here are the original measurements of the drums. I would imagine the actual numbers are nominal but this is what I measured. A friend drew up the print so he could check measurements on some Speedway drums he was having trouble with. Sorry the numbers make kind of an eye chart. A side note is that with the original backing plates and the Wagner z340 shoes I found I needed to mill 1/16" off the sides of the show to make the step measure 5/16" and sit correctly on the Lincoln plate. This is probably unnecessary with the repop backing plates. The assembled plates Ok, that's the background.

Here are some pics of the drum and backing plates that show the before of the drum and the extra splash ring on the plate. The drums do actually clear but just barely and I figured paint, bearing play, or drum flex would set up a rubbing scenario.
To fix it I cut 0.100" off the OD of the drum lip. I chose to go further than necessary and creates a sort of third "rib". This was primarily an aesthetic decision. To hold them I made a mandrel that had a pilot. By cutting this in the lathe before mounting the drums it eliminated any run-out or dialing in.
The two shots above have clearance even though it's hard to show in a picture.

Finally this is the list of parts I have used to assemble the Lincoln brakes.

Hopefully this info is helpful to anyone in the same situation.

 

great info

 

and nice workmanship and skills

 

Do these drums mate up to 41 Lincoln hubs to work with 41 Lincoln backing plates or do you use 46 to 48 Ford hubs ?

 

Sorry I can't answer that. You'd have to reference the dimensions I gave in the first pic. I used 41 Lincoln backing plates and 1937 Ford hubs.