Turning Brake Drums

The wheels are all the same just go to your local auto shop....

If they mount them for you just be sure they don't get over anxious with the wheel grease... Too much gets into the electric brakes and makes them non working pretty easy...

Roy Ken

RoyB wrote:
The wheels are all the same just go to your local auto shop....

If they mount them for you just be sure they don't get over anxious with the wheel grease... Too much gets into the electric brakes and makes them non working pretty easy...

Roy Ken

Trailer drums are not quite the "same" as automotive drums.

Trailer drums have a machined surface on the inside FACE of the drum.

If I understand the OPs post they are asking if the MAGNET face of the drum can be turned.

The answer is maybe.

This will highly depend on the lathe that the shop has, most automotive lathes are not designed to be able to machine the magnet surface.

You will have to ask the machine shop if their lathe can reach that surface..

No if the OP is talking the BRAKE SURFACE then yes, any machine shop which has a brake lathe can resurface the BRAKE surface..

Please note, though, most auto parts places no longer turn down brake drums or rotors so you may have an extremely difficult time finding a place that will be able to do this at all..

You might be able to find a NAPA store that may still have a brake lathe but most big box stores don't.

You can buy new drums for $40-$50 each c/w new bearings. I bet that it would cost about the same amount to turn them, if you could find a place that would do it.

I was speaking of the inside face of the drum where the actuating magnets make contact with the drum. Mine are currently not very smooth. I am replacing everything else (complete backing plate assembly) so I figured I should give the magnets the best chance of working by smoothing out the surface they ride on.

Boon Docker wrote:
You can buy new drums for $40-$50 each c/w new bearings. I bet that it would cost about the same amount to turn them, if you could find a place that would do it.

No, it doesn't cost as much as new drums..

Last time I had a auto drum turned it cost about $10 per drum, that was at least 20 yrs ago.. Might expect $15-$20 per drum now days..

If the drums have enough meat in them and you are turning 4 drums at $20 per drum you will spend $80 vs $200 at $50 for new drums..

There is nothing wrong with having a drum turned provided it is not worn past the max inside diameter.

The only reason to replace is if it will require to much removal of material past the max diameter or the drum is too far out of round.

People now days have gotten rather lazy and are willing to pop for new drums..

Memphisdoug wrote:
I was speaking of the inside face of the drum where the actuating magnets make contact with the drum. Mine are currently not very smooth. I am replacing everything else (complete backing plate assembly) so I figured I should give the magnets the best chance of working by smoothing out the surface they ride on.

You will need to ask the machine shop this question.

Not all brake lathes have the capability to reach the magnet surface (if you ever saw a brake lathe you would understand).

On top of that there is only a small amount of material that can be removed from that surface before the studs are exposed.

Personally, the magnets do not need a real smooth surface, they are capable of moving around a wavy surface.

If you have rust on the magnet surface you can simply use sandpaper to remove the rust and call it good.

I would only consider turning that surface if it had a deeply pitted surface and if it deeply pitted you run the risk of not enough material to remove.

Only a machine shop will be able to give you an answer and only after they inspect the drums (which is why folks here insist that new drums are the way to go).

Yes price a new drum shipped before you go to the shop and spend money.
ALL shops that turn a drum and know their salt can turn the magnet surface.

Face of drum when magnet rides need only be flat/clean enough to 'attract' magnet and hold it enough to rotate so brakes shoes can engage.

Magnet only move 3-4" and then 'slides' on face of drum as it rotates.

Few places have the set up on their brake lathes to machine that inner surface for magnets.

I usually just use crocus cloth or emery cloth and hand sand that inner surface to clean it up

Gdetrailer wrote:

Boon Docker wrote:
You can buy new drums for $40-$50 each c/w new bearings. I bet that it would cost about the same amount to turn them, if you could find a place that would do it.

No, it doesn't cost as much as new drums..

Last time I had a auto drum turned it cost about $10 per drum, that was at least 20 yrs ago.. Might expect $15-$20 per drum now days..

If the drums have enough meat in them and you are turning 4 drums at $20 per drum you will spend $80 vs $200 at $50 for new drums..

There is nothing wrong with having a drum turned provided it is not worn past the max inside diameter.

The only reason to replace is if it will require to much removal of material past the max diameter or the drum is too far out of round.

People now days have gotten rather lazy and are willing to pop for new drums..

He is not wanting to have to brake surface turned, he wants to turn magnet surface. Whole different ball game.

Wow, you need to migrate to the modern world. What cost $10 20 years ago would cost $30-$40 today, if it were only the brake surface that was being done.

Boon docker wrote:
He is not wanting to have to brake surface turned, he wants to turn magnet surface.

OP wrote:
I want to get the surface that the magnets ride on turned on my brake drums

and some say that with my 3rd language English I have hard time to understand it.
Coming to original question, I ditto the suggestion than new drums made in China cost less, than turning Chinese drums in USA.
Get new ones and forget it.