How are brake drums made ?

[Bills65Dart]

Hello good folks.

I have a question, how are brake drums made. Some places I see that the drums are cast. And, I have seen cast drums. But, on my 1965 Dart i am a bit puzzled. It goes for some ther cars too.
It looks to me like the outer part is cast, while the disc on the drum is of a pressed steel plate, and then welded to the cast part. But, that is sort of a little hard to accept, would they really weld a regular steel plate to a cast iron outer ring ?
Or is the drum forged ? I mean the entire thing.

The reason for asking is that the disc on the drum where the 5 wheel bolt holes are is very thin, I would assume too thin to successfully cast it. And it also feels like a little flexible, and that is not a typical "cast iron" thing to be.

I am just curious.

Bill

 

[67Dart273]

I've turned LOTS of drums. Not uncommon to see steel center, cast drum. Some had little "fingers" that became exposed when turning. Almost as if the steel center was laid into a form when the rest of the drum was cast. I have no idea. I don't recall ever seeing an all steel drum

 

[RAT ROD AL]

Differences between Cast Iron and Cast Steel

 

[jazak5]

 

[RustyRatRod]

On the flip side of this subject, there are completely aluminum drums.

 

[Bills65Dart]

I've turned LOTS of drums. Not uncommon to see steel center, cast drum. Some had little "fingers" that became exposed when turning. Almost as if the steel center was laid into a form when the rest of the drum was cast. I have no idea. I don't recall ever seeing an all steel drum

Thanks. I have looked at several movies on youtube, but non are for brake drums for a 1965 Dodge Dart with 9 inch brakes. They are mostly for how large truck brake drums are made, I mean like commercial large size trucks and buses. In addition to my car hobby I have had Ferguson farm tractors as a hobby, and those have 14 x 2 inch drum brakes, and those are completely cast, both the outer ring and the center of it. Cast in one piece, but the center is rather thick. Not like on my "baby Dodge" as my wife call my car.

Putting the steel plate center in the sand form sounds like a way that might work. I never thought of that.

Bill

 

[jazak5]

how about the buick aluminum/cast iron hybrid of the 60"s ? worked very well just to costly to produce.

 

[Bills65Dart]

how about the buick aluminum/cast iron hybrid of the 60"s ? worked very well just to costly to produce.

Are you talking about the, was it 215 V8 engine ? If that is what you think about, the Rover in England bought it, and changed it into casting only the aluminum part, and then machined the cylinders, and pressed in the liners.

Bill

 

[MoparMike1974]

On the flip side of this subject, there are completely aluminum drums.

I had a 65 Buick Wildcat with aluminum drums. They were VERY light.

 

[Phreakish]

Methods have changed over the decades.
US2476151A - Method of making brake drums - Google Patents

Centrifugal casting into, onto, or around a sheet metal flange or housing is pretty common. There's even patents which disclose centrifugal casting apparatus which spin fast enough to separate two alloys from one another to form an integral duplex metal part. Pretty neat stuff!

 

[67Dart273]

The only aluminum drums I've seen had cast iron inner liners.

 

[Bills65Dart]

The only aluminum drums I've seen had cast iron inner liners.

So, cast iron for the wear, and aluminum for the heat ?

I wonder how efficient that was. To be honest, I like drum brakes much more than disk brakes. Especially after owning a 2004 Mercury Grand Marquis since 2013. What a brake disaster that has been.

 

[jazak5]

Are you talking about the, was it 215 V8 engine ? If that is what you think about, the Rover in England bought it, and changed it into casting only the aluminum part, and then machined the cylinders, and pressed in the liners.

Bill

was referring to post #9 , yeah buick got the best of that deal !!! my buddy's got a rover and they are still expensive junk always in the shop !!!!!!!!!!!!