Brake drum dimensions and stub axles.

eatonaxle

eatonaxle

Junior Member
What is the max oversize for safe brake drums. I was lead to believe it is 3/32" over the std. 11".

To stop the bottom king pin bush rotating in the stub axle, what is the best repair.
  1. Make an oversize bush.
  2. Knurl the outside of the bush and install.
  3. Look for a better stub axle.
What is the correct dimensions and thread for floorboard screws?
 
The maximum oversize for safe Model A drums IMHO is 11.060", and that is for steel, or cast iron. Some may let them go further, but you said safe. The worn steel drums do not dissapate the heat fast enought and you will get brake fade after repeated use. By the way, 3/32 would be 11.1875, way to worn.
 
I'm guessing stub axle is Kiwi for what we call a spindle. Making an over sized bushing would work if the worn hole is still true, but you might find a better spindle for less money and effort.

Jim's right on the drums

floor board screws are 12/24x 1 1/4 in. They require a special cup washer. All available from any A supplier.
 
If he was meaning 11 3/32 dia, that is about 11.094.

So, 11 1/16ths is more exact = 11.063.
 
Jim Parker Toronto said:
The maximum oversize for safe Model A drums IMHO is 11.060", and that is for steel, or cast iron. Some may let them go further, but you said safe. The worn steel drums do not dissapate the heat fast enought and you will get brake fade after repeated use. By the way, 3/32 would be 11.1875, way to worn.
Click to expand...
Thanks Jim. What I meant by 3/32" o/size, is total measurement. ie 11 3/32". Or 3/64" wear each side of the drum, if you follow my drift. Many thanks for your answers.
 
Before going through a lot of trouble to save your spindle with the oversize bushing hole, make sure it has no other issues, like damage where the wheel bearings go, or worn threads. One of my spindles had spun a bearing once upon a time, and a couple of years ago at Hershey I got a couple of suitable replacements for $10 each.

Doug
 
About the floorboard screws: They are #12 by about 1-1/4". #12 is an oddball size, almost as big as 1/4", but here in the USA they can be found in better hardware stores.
I had some leftover conical washers meant for door hinge screws, and I found that they worked very well with the floorboard screws.

Doug

Doug
 
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