H: Hubs, Wheels and Tyres Brake drum skimming

Monkeypants

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I can only say that the emery method worked for me. I wish Tony Cording still had his Prince with the feeble brakes. I know Dan had a go at it and Robert tried as well, using the proper lathe method of trueing things up. I was told that nothing worked, the brakes remained very weak. It would have been good to try the emery on it.
I think the emery method works because it matches things up as they actually are, rather than how they ought to be. And it takes off just the minimum amount.

Glen
 

Monkeypants

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If i read it well, some say stick some emery paper on the inside of the drum. Rotate the wheel, apply a bit lever and so to grind in the linings.

Very nice way to make lock-ups. As the diameter on the linings will be to SMAL, creating only the leading edge to touch the drum, leaving the trailing part of the shoe into thin air.

No Good.
Too small in radius by the thickness of the Emery, which is negligible. It works fine in practice.

Glen
 

Magnetoman

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I know Dan had a go at it and Robert tried as well, using the proper lathe method of trueing things up. I was told that nothing worked, the brakes remained very weak. It would have been good to try the emery on it.
I think the emery method works because it matches things up as they actually are, rather than how they ought to be.
In defense of the proper method, if they actually had done it properly it would have worked because it matches things as they actually are, as well as how they ought to be, since they're the same. However, it requires turning both the drum and the shoes, not one or the other, and turning the shoes with a shim in place..
 

Monkeypants

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Well those fellows know their stuff better than just about anyone and the D brakes remained pretty weak, from what I've heard. The D is missing a drum at back but the front should be capable.
Maybe there was something else amiss.
I mentioned this method to the A 10 forum and was told by several that it wouldn't work.
Then a couple of fellows actually tried it and had success.
The lathe method is tried and true, however this works at least as well, provided you aren't trying to remove a huge amount of steel.

Glen
 
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Magnetoman

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Well those fellows know their stuff better than just about anyone and the D brakes remained pretty weak,
Not to be argumentative, but assuming someone did properly turn the drum and shoes on a lathe the brake would work every bit as well as the intrinsic design of the brake allowed, but only if the shoes were of the right material.

My objection to what you wrote is the implication that somehow in principle a lathe might work, but in practice it might not. If brakes having the correct internal pieces are turned on a lathe and afterwards they are weaker than other brakes of the same design, it either means the work on the lathe wasn't done properly, or the material for the shoes is wrong.
 

Monkeypants

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There is some slack throughout the system, particularly on an old well worn motorcycle. When set up in the lathe we simulate how things are with the brake applied. This is not necessarily exactly the same as when the whole assembly is installed and working on the bike, particularly with the brake plate. Do the shoes move out exactly the same on the lathe with no drum fitted as they do on the bike, or does one shoe cant off a couple of degrees when it initially contacts the drum? Does the other shoe shift back a bit, taking up some slack in the pivot?
It's very hard to know for sure, but the emery/ assembled method will take that sort of movement into account. How things actually are, as opposed to how they ought to be!
A couple of thou here and there, a degree or two of cant
could add up to sub par performance.
That's my thought on it.

Glen
 
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Martyn Goodwin

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Not all of us, in fact very few I suspect, have access to, or skills to operate, a Lathe and or Mill.

So with only rudimentary tools it seems to me that the emery cloth/paper solution is at least one way for us to try improving our brakes, all be it that it will be a slow process.
 

Peter Holmes

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VOC Member
It would make you cry if you knew what Conways had in the 60s !!!!, Not a lot !.
It did, I had some significant work done on my crankcases in 1966, when I collected the crackcases with very little knowledge, only Paul Richardson’s book and a hand book, it quickly became apparent the work had been well and truly bodged, timing chest spindles at different heights and loose spindles only retained with a visible brown substance and still loose to the spanner, main bearings severely staked (OK I know the factory did this also) but I think Conway’s was at a very low ebb back then, hope that was not in your time there Bill.
 
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