Topic: Brake Disc Question of the Day

[oldhatt45]

About to finish up putting my front wheel.
But before I do it, I was wondering about whether I should try to do a little surface finishing of the Front Rotor.  I did a forum search and looked at the How-To section but all that was there was a short video of one of the guys here putting their rotor on a lazy susan and using what looks like a dremel or rotozip with a sanding disc maybe. 

Was hoping to find some info on resurfacing the Rotor.  Would appreciate any tips, or info on how to do it.

Thanks,

Charlie

[754]

Blocksanding with sandpaper on a lathe works very well,  if there is no deep grooves..minor stuff seems to come out.
 Hard part is getting a lathe to use, I abhor the use of sandpaper or emery on my best lathe for a few reasons.. First a thorough clean up and see due afterward, and second its a lathe killer.
 But covering the ways and carriage with paper or cardboard...wrapping chuck with saran or shrink wrap helps  a lot.

[oldhatt45]

754,

Thanks. 

What grit sandpaper to use???
Don't have access to a lathe, but I have some long block sanders that I used when working on fiberglass boats.

Rotor is not bad and has no "scratches", but I would like to clean it up a bit.
I think I've got plenty of Rotor left.  It measures 7mm, so not worried about taking material off.

Charlie

[edwardmorris]

Get it Blanchard ground, takes off next to nothing and comes out pretty. Member Godffrey now offers this service too

[754]

Might be able to spin it in a drill press if you make an adaptor.. ..not too fast ..support other end..
Probably 220 or 320 grit..

[oldhatt45]

754,

Thanks, that's a good idea.
Also appreciate the info on the grit of sandpaper.

What about using a DA sander?  All I basically want to do is to give the rotor a fresh surface.  Almost like just breaking the "glaze".

Edward,
I'll have to check and see if I can get a Blanchard grind done.  Thanks.

Charlie

[edwardmorris]

The machinist that did mine cautioned against DIY, unless you have a really good set up to keep the rotor "true" by the time you're done with it. Blanchards have micro something accuracy, where as any manual sander/ing will be far from it. I'd send it to Godffrey, or at least have a chat with him before a DIY attempt. My $0.02 of course.

[754]

You would be hard pressed to remove 2 thou a side with the sanding, as long as it keeps turning while sanding.. The big plus is it generates a stock looking finish, which some other methods do not.
 DA might help just be sure to lift off slowly..

[Airbusboy]

I've also got the rotor on my '74 CB550 that I'd like polished while I have it off this winter getting the wheel trued. How do I/we reach the infamous 'Goddfrey' to have him do his magic on the rotor?  Thanks, guys!

[Paul Lowe]

I went the lathe method with flap sander on a cordless drill. Came out perfect and it had some nasty scratches.

[jmelche2]

I've also got the rotor on my '74 CB550 that I'd like polished while I have it off this winter getting the wheel trued. How do I/we reach the infamous 'Goddfrey' to have him do his magic on the rotor?  Thanks, guys!

Yes, I'd like to find out more about this member.  How do we contact him and where is he located? 

[Oldtech]

Here in Ottawa we have a company called General Grinding that does that sort of work at a reasonable price. Check around in your area. There has to be someone doing it.

[flybox1]

I've also got the rotor on my '74 CB550 that I'd like polished while I have it off this winter getting the wheel trued. How do I/we reach the infamous 'Goddfrey' to have him do his magic on the rotor?  Thanks, guys!

just visit his garage    I'm running two of his drilled 4mm rotors.  good stuff!

http://www.vinmoto.org/gallery/v/VinMoto-Garage/album03/Godfferys-Garage-123/Parts+and+service/

[754]

I would caution about putting it on a bench grinder.. For a few reasons..
 First being. The rotor is not designed to turn at those RPMs, if the carrier fails, the next two or three seconds will get very ugly..

 If you try putting on a drill press, make sure the speed is low enough.. Some small ones are too fast, plus the machine is too light should there be some imbalance.
 And it's easy to not have it running true without a purpose machined adaptor

[edwardmorris]

I've also got the rotor on my '74 CB550 that I'd like polished while I have it off this winter getting the wheel trued. How do I/we reach the infamous 'Goddfrey' to have him do his magic on the rotor?  Thanks, guys!

just visit his garage    I'm running two of his drilled 4mm rotors.  good stuff!

http://www.vinmoto.org/gallery/v/VinMoto-Garage/album03/Godfferys-Garage-123/Parts+and+service/

Or PM him, http://forums.sohc4.net/index.php?action=profile;u=7132

[Dunk]

I just did quick and dirty with a line sander. Forget what grit, probably 80 then 120 or 150. Not perfect but much better than it was. Just kept it spinning on my bench and going around it with the sander.

[dave500]

ive deglazed them with a big flat sharpening stone and soapy water over a couple of beers worked fine,ive also laid a trolley on its side with the disc sat on a wheel and spun it while I shot it with the sand blaster worked well,its hard material.

[oldhatt45]

OK, so with all that was said,I took my rotor down to the local machinist and ask him if he could just reface the rotor.  Dropped it off just before lunch.  He said if he could mount it up on his machine then no problem.  Got home, just finished lunch and the phone rings.  It's the machinist.  He said "come get your rotor".  Wasn't sure whether he was able to do anything, so went and picked it up.  Perfect.  He only took off 0.14mm.  Went from 6.99mm to 6.55mm.  All for $13.00.

Oh, and I did things a little bass akwards.  I just have to wire wheel some light rust spots off and maybe touch up the paint.  Next Rotor will do in correct sequence. 

Did I do OK with this Rotor?

Thanks,

Charlie

[dave500]

yep that's cheap.

[Retro Rocket]

yep that's cheap.

+1 

[754]

That wood be cheap at double the price..is it both sides..

[oldhatt45]

754,

Yep, both sides.  Other side looks the same as the one in the picture.

Thanks Guys,

Charlie

[edwardmorris]

Good deal! Looks pretty close to a Blanchard finish.

For the surface rust on the center, steel wool and diet coke work great. I did my initial cleaning of all chrome parts that way, was shocked how well it worked. Diet won't leave it sticky, and works just as well as regular. Its the phosphoric acid that helps..

[dave500]

they would want 15 bucks to set it up here let alone actually machine it!

[Stev-o]

Very good deal.  I suggest painting the entire middle section rather than touch up. Use caliper paint.