Can brake drums be resurfaced on 1918 DB Touring?

[Willy]

My drums are pitted - can they be resurfaced, or do I have to get others? Are there new ones?

[Mattml430]

27 minutes ago, Willy said:

My drums are pitted - can they be resurfaced, or do I have to get others? Are there new ones?

They are generally pretty thin and worn to a not so perfectly flat surface. If there’s enough meat there you can but every chance they’ll be pretty thin by now. I have seen people weld on rolled steel to the drum face. 

[Minibago]

Good ones are hard to find now, machining the rust pits out is not a safe option.

I have changed several drums for DB owners which have been machined to remove the braking surface and a steel ring welded in. The steel does not provide a good braking surface nor a long lived one.

No weld procedure was used and having braking on the rear only safety has to be the most important consideration.

I have several sets of spare drums here in Australia but the freight would be very expensive. Perhaps other DB owners could offer a replacement pair.

Have you contacted either Romar or Myers?

[Willy]

Not yet - right now I’m looking at options.

[gossp]

Generally speaking a call to Romar or myers is the first step towards finding out what your options are. As often as they will offer to sell you something they will steer you towards a private individual that they know will have what you are after. 

[Mark Gregush]

To surface them you would have to make an arbor to hold the drum, would also need to be made to fit the tool it was used on. The arbor would have to center the drum to turn it to match the wheel center when it was remounted. Except for a very few people, not and off the shelf job. Not a job that could be done on the average drum lathe without the proper bits to get it setup. 

Edited March 19, 2023 by Mark Gregush (see edit history)

[Machinist_Bill]

On 3/17/2023 at 11:16 PM, Willy said:

My drums are pitted - can they be resurfaced, or do I have to get others? Are there new ones?

Many years ago as a young man as an apprentice I sleeved a bunch of old drums because of lack of $$$. 0.0005" fit per inch diameter and my Mother's oven (When she wasn't home) 500 degrees and drop in the sleeves. Slow cool.... Large diameter cast iron pipe was everywhere for scrap price! PVC pipe came along and there went my supply.....

You can try: https://www.jgrelining.com/

Just an option in case a replacement is unavailable.

 

Bill 

[Mark Gregush]

Adding a sleeve to either the inside or outside, you might run into issues installing the parking or service brake shoe(s). The drum has to be X thickness to be usable and if you turn it to work, the sleeve would be really thin, so would be worthless. 

Wonder if they could be spray welded then turned back to proper size? 

[JACK M]

20 hours ago, Mark Gregush said:

Wonder if they could be spray welded then turned back to proper size? 

I have heard of that .

[Willy]

I’m looking for someone local to do that. I never intended to put it on a lathe and machine it, I was going more for ADDING to the surface, then putting it on a lathe. This drum is using both the inner and outer surface, but I think only the outer surface needs fattening. The inside shoes would be adjustable to accommodate….. I think….

[Willy]

I always think outside the box, because nobody will let me back in the box, and I’m thinking, “what if the brake shoe (outside portion) were attached to the DRUM, and an iron rim was on the outside? It would still have the same properties either way, to my foggy way of thinking - at least until I could find a reasonable replacement. Why couldn’t drums be resurfaced by spray welding or molds? This is a problem with many rare antiques, so it might be a solution…..

[Minibago]

38 minutes ago, Willy said:

I’m looking for someone local to do that. I never intended to put it on a lathe and machine it, I was going more for ADDING to the surface, then putting it on a lathe. This drum is using both the inner and outer surface, but I think only the outer surface needs fattening. The inside shoes would be adjustable to accommodate….. I think….

The inner shoe (handbrake) is one piece and not adjustable, the shoe does not move out to the drum as one piece, it expands by flexing, it is liable to crack / break in half if required to move too far in it’s application.

[Minibago]

1 hour ago, Willy said:

I always think outside the box, because nobody will let me back in the box, and I’m thinking, “what if the brake shoe (outside portion) were attached to the DRUM, and an iron rim was on the outside? It would still have the same properties either way, to my foggy way of thinking - at least until I could find a reasonable replacement. Why couldn’t drums be resurfaced by spray welding or molds? This is a problem with many rare antiques, so it might be a solution…..

Perhaps thinking outside the box makes the process un-necessarily complicated.

The brake shoe cannot be connected to the drum.

You could have the brake lining material attached to the drum.

You would then require the steel band (you refer to it as “the brake shoe) to accept all the wear / heat transfer while providing sufficient, “ SAFE “braking when mechanically applied.

Not the same properties by any stretch of the imagination.

Not realistic or feasible.

Time, money and re- engineering. 
Compliance with local Road Traffic Authority regarding engineering design approval.

 

Cutting the drum and welding in a ring of suitable material.

Weld procedure / test / welder qualification to weld procedure.

RTA compliance as above.

 

Metal spraying will provide extra material thickness and has been around in several different forms since about 1910.

Mostly used for corrosion protection or for wear protection.

However the friction coefficient is what is required here, most materials used for spray welding are designed to minimise friction.

A metal that will continue to provide friction (braking) under great heat situations without fading is required.

 

Or you could call Myer or Romar to see if they have a pair of second hand drums.