Turning a brake drum

bobv

bobv

Senior Member
I have a front brake hub/drum that I would like to have turned to clean it up. It doesn't have bearings or races in it. Can this be done without the races installed?
Is there an acceptable amount of out of round?
Thanks
 
You want to do it with the races installed to give it a true surface as the same as being installed on the car. If its an original steel drum they don't cut good for a nice finish. I like to only cut the cast iron's
 
Bob,

The races would have to be installed to turn it... They are what the drum would be centered on to turn and run on when in use. Races are cheap... it's just the cost of doing it.

The original drums were probably not meant to be turned... but we all turn drums to true up and ensure good braking. I don't like original drums with bands or otherwise on to be more than .075-.080 thousandths over the standard 11.0 inches. With the availability of the new cast irons they are a plus... I prefer the late '31 and service replacement 11 inch cast irons myself if can be found.

If you have a good sharp cutter, mount a wheel to the drum/hub, and use an anti-chatter belt the steel drums can be successfully turned with care. Sometimes it's just a matter of a few thousandths to clean them up. I once took about .003 to cure a slight pulsating pedal. It was great after that.

Yes... races have to be installed.
Larry Shepard
 
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I thought they should probably be installed, I was hoping to at least check if it is round then go from there. I will install races and spin it to check if it's out of round first.
Thanks
 
Actually it's all in the tool you use.
Since it's steel so most all brake lathes are set up for cast iron tool bits.
Cast iron crumbles and Steel is stringy when it cuts so you need a tool bit that cuts steel.
You'll also need the rubber band for the perimeter as it will ring like a bell"chatter".

Like the others have said above you need your races in place as that's how the drum is going to revolve. I would also check the thickness of the drum as it can't be any thinner than a 1/16" .
 
I talked with the guy who would turn it, he said he didn't think he could get what he considered a smooth cut on those drums, he did say that it would come off in strings. He was also concerned that it wouldn't be round, he said they can warp over time. I guess we need to spin it with races in to see if its warped.
 
I installed the bands from Snyder's and found that they tightened and distorted the drums so much I had to have them turned, I also at that time relined the shoes. Braking was much improved for about a 1000 miles. Than it seemed to fade so I removed both drums to inspect what was going on. I found both drums badly grooved, kind of looked like a corn field that had been plowed. Did this have anything to do with turning the drum to much, did they get them to hot?

Just to add the drums looked very good after they were turned, nice and smooth.

to damn cold in WV

dusty
 
Boby,
Your other option would be to switch to cast iron drums. Of course there is process and expense in it as well. Any drum can warp in time and get out of round. That's the reason for turning to true them, no matter if they are steel or cast iron, you still need true drums. You would be best served finding someone in your area who does Model A work who turns drums or an old time machine shop who will take care to do it. You must take light cuts and care in doing it. I have done hundreds and I guess I am just use to doing it
Tom Wesenburg is in MN... maybe he can refer to someone in your area...? I just mapped you and looks like your near Brainerd. I think there is a V8 Ford contingency up there. You might try someone on the V8 sight as well. I go up every year to Greenbush... pretty country up your way and enjoy the trip every year
Best of luck,
Larry
 
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Dusty said:
I installed the bands from Snyder's and found that they tightened and distorted the drums so much I had to have them turned, I also at that time relined the shoes. Braking was much improved for about a 1000 miles. Than it seemed to fade so I removed both drums to inspect what was going on. I found both drums badly grooved, kind of looked like a corn field that had been plowed. Did this have anything to do with turning the drum to much, did they get them to hot?

Just to add the drums looked very good after they were turned, nice and smooth.

to damn cold in WV

dusty
Click to expand...

Warnings were always posted with a new brake job to be sure to do easy braking for the first thousand miles to avoid grooving the new linings and drums. This was in books, and maybe also with the linings I bought years ago, but I haven't heard mention of it lately. I still think it's good practice and ALWAYS try to brake easy. :)
In an emergency, you do what you have to do however.:eek:
 
Be careful about turning steel drums, they are thin to start with. But if you do turn them, wrap the drum with a bungee cord. Use a sharp tool bit with fine feed and slow speed.
 
Tom Wesenberg said:
Warnings were always posted with a new brake job to be sure to do easy braking for the first thousand miles to avoid grooving the new linings and drums. This was in books, and maybe also with the linings I bought years ago, but I haven't heard mention of it lately. I still think it's good practice and ALWAYS try to brake easy. :)
In an emergency, you do what you have to do however.:eek:
Click to expand...

Thanks Tom, I never knew this, having said that I don't think as far as braking goes that I'm ever hard on them....except when I'm trying to stop:) I will order a set of cast iron drums for the front before spring, I have already acquired a nice set of hubs ready to be pressed in. I hope this will improve things.

dusty
 
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