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I found these forks online for a very good price, however, they have a small scratch in the tube. It looks like something I could probably sand and make smooth, but would like a second opinion. Thanks

You do not want to sand a seal surface. A nick can cause complete seal failure or just a leak or nothing at all.... just kinda depends.

Just about any forks you find will have some kind of defect on the tubes. If it is not too bad.... don't worry about it.

You can sand it, that's no problem.
I think 320 grit is probably the coarsest I would use. The fork tube is hard chromed, a little emery cloth won't hurt it at all. It's ground, and polished that way when new.

They sure are.. to a very specific grind to ensure seal. I don't think anybody can accomplish this with sand paper....

They are polished with emery cloth, post grinding. Trust me, it's not that critical, and there's no black magic.
I am a machinist, and have done 100's of them.

I agree, if it does not leak, gently sand them with the finest grain sandpaper you can find. Lay the paper or emery cloth around the fork leg and buff them like you were polishing someone shoes on a shoe stand. Don't sand against the grain. Good luck.

I'd be sticking with emery cloth 320 or 400 - Zomby woof is correct.

Hockeyboysomers - what is "...against the grain" comment relate to on forks?

Buffing the fork tube e.g. " like polishing shoes on a shoe stand" or - working the emery cloth perpendicular to the scratch I think was what you meant and would be correct IMO. .

I guess all I learned in Caterpillar engineering classes was all a hoak. Good luck....

You need to remove any burr/pile up on the edges of the scratch. I work on aircraft and when we get a nick in a turbine blade we use polishing stones. They look like something you could use to sharpen your pocket knife with. I'm sure you could find something like that at a place that sharpens tools, like a hardware store. You don't want to make the damage any bigger, just polish the scratch by moving along the length of the scratch. You could even use some fine emery cloth wrapped around something like a coat hangar, anything that's small diameter and a little stiff. I've done that on any small dings I find in my fork tubes on any of my bikes, even if they don't leak yet. Been doin that for years and it seems to work ok.

Yes... you can level the nick but that's as far as you want to go....

Well, these forks are on eBay, so I cannot inspect them in person. I think I will just leave them alone and look for better forks.

Bah! Knock the edges (if there are any) off that nick, they'd work fine.

Look at all the other pits and sparkly-dings up and down the tube in the pic. I'd be more worried about all those pits...kind of an indication the forks weren't protected in the first place.

Even at that they would probably seal up just fine.

Ha! Like USChrome told me 'bout my sandblasted/pitted/messed up cylinder, 'The pits are actually a good thing...give oil a place to 'live'.'

Happy Hunting!

Indawoods wrote:I guess all I learned in Caterpillar engineering classes was all a hoak. Good luck....

IW - I believe that the hydraulic cylinders in Cats likely run somewhere in the 2800-3500 psig range. Bike forks don't see that kind of pressure and that is one reason that you can polish the forks without compromizing the seal.