Min. thickness for turning brake rotor/chrome plating centre

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Hello all. I want to turn one of my original rotors and chrome plate the centre part. Anyone chrome these successfully? Should I think about powdercoating the centre instead?

The reasoning is that I have a nice shiney new Brembo rotor up front with a polished centre and I want that ratty looking rear disc to match somewhat.

I might as well get the rotor turned while I have the bike apart and i am wondering what the minimum thickness is just in case.

Thanks to all who reply.

Regards,

Colin.
 
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Hi,
I am not sure about a minimum thickness figuere for the disk. I recently cleaned up mine by putting the disk in a lathe and while it spun I used an air die-grinder with one of those two inch abrasive scotch-brite pads (I suppose you could use any type of sanding disc). I didn't have any deep grooves to remove and it cleaned up real nice, and probably removed very little material. Regarding the chrome, I don't know how you would go about chroming just the center, but, I suppose it could be done, same for powder coating, which for the size and application I think is a little overkill, a little silver paint is cheap and easy.
GB
 
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Re: Min. thickness for turning brake rotor/chrome plating ce

Coco said:
I might as well get the rotor turned while I have the bike apart.

You probably already have a source for turning your rotor, but if not, I can recommend the following: http://www.tritonmachining.com/new_page_3.htm

As an aside, and I've been meaning to tell you this, because I know you are rebuilding your forks currently, he also manufactures (no longer on his website, probably because he's wholesaling them out) top quality fork nuts (stainless) that allow you - via two holes drilled in each nut - to change the fork oil without removing the nuts. Very nifty units. If you e-mail and ask him the price of these units (sorry, I cannot say fork nuts too often without feeling like I'm a character in South Park), I suspect he'll get back to you with a quote. I think I paid around $50 U.S. dollars for the pair. If you want a picture of them to make sense out of the above, I'll try and remember to take the camera to the shop.

I understand your need for symmetry with the front and back brake. Geo46er is always sage in his advice, and thrifty. Goodly man. I always read his posts. I have a drum back brake (and thus nothing to match) and merely painting the center circle of the rotor worked fine for me. It took a few tries to get the right color of silver, though. And when I got the new tire put on they scuffed the hell out of it anyway. Alas. I figure it will catch a few rocks on the road either way.

Cheers--

w/
 
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Disk Brake Repair (DBR) out of Indiana takes them down to .200 from the stock .250 we have about a dozen of these running around Michigan for the last several years. Their AD is found in the Norton News.
 
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Nothing is overkill on this project as I'm building my "dream Commando" and if I pay extra for a chrome plated rotor centre, I have no qualms about it. It has to look right or I won't be happy with it.

I'm thinking a powdercoat might be the easiest route. If chrome plating firms can tape off areas of items that are to remain chrome free, I'm sure they can do a disc centre. Possibly :roll: .
 
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Remember one point. I had mine turned a number of years ago because it had gotten warped...something about difference in heat disipation between the original chome plating and the cast iron the chrome was plated onto... and since then, I have wished I had just bought a whole new one instead. Reason being that when the disk gets turned, there is naturally a certain amount of material lost, it ends up thinner. The brake caliper, and the thickness of the brake pads, is calculated with the thickness of the original disk in mind, not with the thickness of a turned disk. The pads now will stick further out of the caliper as they have further from the original specs to go to get to the rotor and make contact. The pads are then loose, and no longer have a tight fit in the caliper. They literally get "cocked" in the hole they sit in. They will make a clack, clack when the brakes are not being activated and you roll the bike forward. You will have to replace the pads much more often than normal, because the point where the steel pad backing starts to get close to looking out of the caliper will happen much faster, much less mileage will be gotten out of a pair of pads. and the looseness of the pads in the caliper will gradually enlarge the place they sit in the caliper...which makes them clack more. Visicious circle.

Bottom line. You make the caliper wear out quickly. You get noisy brakes that come on with a clack and a lurch and you buy pads twice as often as you would if you had just bought a new rotor and painted the center to your own taste. I have ridden with a turned rotor now for a while, and when I get a bit of cash, it will be one of things I replace. If you want your dreambike, invest in a new rotor, rather than turning down an old one. More bang for your buck.
 
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hewhoistoolazytologin said:
Bottom line. You make the caliper wear out quickly. You get noisy brakes that come on with a clack and a lurch and you buy pads twice as often as you would if you had just bought a new rotor and painted the center to your own taste. I have ridden with a turned rotor now for a while, and when I get a bit of cash, it will be one of things I replace. If you want your dreambike, invest in a new rotor, rather than turning down an old one. More bang for your buck.

Good point. A nice drilles, 11" SS rotor is $300 CDN from Walridge. It will probably cost me $75-$100 CDN for a chrome job and about $15 or a box of beer for a powdercoat done locally.

My rotors are in quite decent shape but I figured a quick turn couldn't hurt.

Hewho, your points are food for thought. Thanks.
 

Ron L

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hewhoistoolazytologin said:
Bottom line. You make the caliper wear out quickly. You get noisy brakes that come on with a clack and a lurch and you buy pads twice as often as you would if you had just bought a new rotor and painted the center to your own taste. I have ridden with a turned rotor now for a while, and when I get a bit of cash, it will be one of things I replace. If you want your dreambike, invest in a new rotor, rather than turning down an old one. More bang for your buck.

Hmm... I had the chrome turned off a couple of mine a few years back and have no noise at all. Anyone else have Hewho's experience?
 
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The original rotors were chromed?

Should I just get my whole bloody rotor chromed after a turning is done?

I'm new at this brake rotor thing.
 
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I would be concerned that, by chroming the entire rotor, you might adversely affect the coefficient of friction between pad and disc. Most pads available to run in the original Norton Lockhheed calipers have compounds which are designed to mate up with cast iron rotors. Chromium plating this surface could give unpredictable braking performance.
Stainless rotors on many modern bikes have pads developed specially to grip stainless. But serious performance brake manufacturers, like Brembo for example, make floating discs with alloy hubs linked to cast iron rotors.
I would be inclined to leave the cast rotor alone. Powder coating still looks good. Even trying to chrome plate the disc centre could be beset with pitfalls. Chrome plating is porous and needs copper or nickel pre-plating to avoid peeling and rusting. Chrome plating carries the risk of hydrogen embrittlement.
It looks might pretty but chrome is not all it appears.
 
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scim77 said:
I would be concerned that, by chroming the entire rotor, you might adversely affect the coefficient of friction between pad and disc. Most pads available to run in the original Norton Lockhheed calipers have compounds which are designed to mate up with cast iron rotors. Chromium plating this surface could give unpredictable braking performance.
Stainless rotors on many modern bikes have pads developed specially to grip stainless. But serious performance brake manufacturers, like Brembo for example, make floating discs with alloy hubs linked to cast iron rotors.
I would be inclined to leave the cast rotor alone. Powder coating still looks good. Even trying to chrome plate the disc centre could be beset with pitfalls. Chrome plating is porous and needs copper or nickel pre-plating to avoid peeling and rusting. Chrome plating carries the risk of hydrogen embrittlement.
It looks might pretty but chrome is not all it appears.

Very good points.

I'm not totally sold on the Chrome plate but was considering it. It seems as a powdercoat will be better and far cheaper option anyway.

The rotor on my front Brembo system is stainless on an aluminum hub, not iron. http://www.coloradonortonworks.com/catalog/brakes.asp

Something like a Ferodo platinum pad should work fine on stainless, no? that is if I go the route of a stainless rear rotor from Walridge, but that would be my most expensive option.

I think for now I'll powdercoat the centre on the stock disc and before that happens, drill it out to somewhat match the Brembo on the front.
 

Ron L

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Coco said:
The original rotors were chromed?

Yes, originally the rotors were chromed. It wore through quite quickly, although generally not in a uniform manner. When the chrome was removed, the braking improved considerably, but you were left with the rusting problem if you get them wet or they stand for a while.

I prefer to have the chrome turned or ground off when the rotor begins to show bare steel.
 
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