Finishing a Seal Surface

[Clatter]

So,
i got my spindlwes back from the powdercoater.
And they blasted the surface where the seal rides....

Was planning on polishing it back up,
So the seal doesn't get eaten by the rough surface.

How fine does this have to be?
Is it a case of more is better,
Or is there a certain finish that works best, like with honing piston rings?

Was going to polish them with some 400 wet/dry, then maybe some 600.
Maybe go all the way and Polish polish?

Same with flywheels at the seal.
Was planning on sanding the old marks from the seal,
And polishing it until smooth.

What's the skinny?
Anybody know for reals how this goes?

[SCOTTRODS]

So,
i got my spindlwes back from the powdercoater.
And they blasted the surface where the seal rides....

Was planning on polishing it back up,
So the seal doesn't get eaten by the rough surface.

How fine does this have to be?
Is it a case of more is better,
Or is there a certain finish that works best, like with honing piston rings?

Was going to polish them with some 400 wet/dry, then maybe some 600.
Maybe go all the way and Polish polish?

Same with flywheels at the seal.
Was planning on sanding the old marks from the seal,
And polishing it until smooth.

What's the skinny?
Anybody know for reals how this goes?

Get a new powder coater.... they should know better than to Blast a Seal/bearing surface.... cheap to mask too... wrapped with Gorilla Tape and no problems. I do stuff like this all the time and never blast those types of surfaces.

[Piledriver]

I think the blaster needs to pay to have them resurfaced or even resleeved if it's very bad.

You want that as smooth as possible, it used with a rubber lip seal.

[Ol'fogasaurus]

"... Was going to polish them with some 400 wet/dry, then maybe some 600..."

Pile is correct that they have to be very smooth, I think they (the races the seals ride on) are a ground surface from the factory. I think finishing with a 600 grit is still too rough; think of running your hand along the sandpaper at a high speed for hours on end. Without knowing for sure, you maybe need to exceed 1000 grit and maybe as high as 4000 grit, not sure about that but suspect that it could be getting closer to the smoothness needed. Also the surfaces that the seals ride on have to be square along their face too, no grooves even like finger pressure induced groove you could get during sanding would be wanted.

One would think that the person's doing the blasting would know have known better than to not protect those surfaces. You also need to put a protection of light oil of some kind on the bare surfaces as their is something about the beading that allows metal to rust faster after being done.

My two-bits on this

Lee

[SCOTTRODS]

I think the blaster needs to pay to have them resurfaced or even resleeved if it's very bad.

You want that as smooth as possible, it used with a rubber lip seal.

The coater is the one you left them with last.... He is actually the one responsible.... Pretty much ruined unless redone properly. A new different size seal may be necessary as well, if ground down to a polished finish. Seems to me, if it's something as obvious as that, the coater should be beaten with a shrubbery, or cut in two with a herring (or some other such Monty Python type Punishment).

[Clatter]

i live in California, what can I say.

Here, you have to do everything yourself, if you want it done right.

See, everybody in America who couldn't make it,
or everybody hated, or was crazy, or a loser, was chased off to the West.

Eventually, they ran into the Pacific ocean, and couldn't go any farther, and accumulated there for over a hundred years.

if i take it to someone else here, the chances are very slim that the result will be any better.
My plan is to cut strips of different grits of emory cloth and git 'er done.
Will use flat strips, and maybe wrap with cord for that flossing-like action,
similar to what some used to do to polish crank throws.
Should keep the finger-grooving to a minimum.
it's some kind of glass bead, not sand or anythng too bad.

there is a polisher nearby i could go and talk to.
And, he came from England, so there's hope...

[Bruce2]

Should keep the finger-grooving to a minimum....

After many thousands of miles, the spindle's seal surface doesn't look so great after dirt gets in it.
I usually sand it with 320 to smooth it out. Don't worry about your fingers making a groove, you're not going to be able to remove very much. Steel is much harder than paint (where your fingers will leave impressions).
Finish with 400 or 600. There's no need for a chrome like finish. The factory never did anything like that.
This is not a big deal. I have always refinished my spindle's seal surface this way. The seal always ends up working fine afterwards.

[Piledriver]

Bruce, you bead blast your sealing surfaces first?
(I kid, but that IS what we are talking about)

[Ol'fogasaurus]

Bruce, you can put finger groves in sanded surfaces besides paint and wall mud. It depends on how hard you (have to) work at it and how you do it. I usually recommend using a hard surface to attach the sanding material to to eliminate the possibility. Remember, sanding, polishing and grinding is just wearing away the surface using different abrasive media to get a finer/smoother surface.

Lee

[Bruce2]

Bruce, you bead blast your sealing surfaces first?
(I kid, but that IS what we are talking about)

A bead blasted finish is not very rough. I could have that cleaned up in less than 10 min.

[Bruce2]

Bruce, you can put finger groves in sanded surfaces besides paint and wall mud. It depends on how hard you (have to) work at it and how you do it. I usually recommend using a hard surface to attach the sanding material to to eliminate the possibility.

In the case of the seal surface, your finger covers the entire width at once, so you're not going to make a groove.

To the OP, this is not a big deal. Spend 10 min with some 320-400-600 with your fingertips then move on to assembly.

[Bruce2]

Due to Lee's prompting, I did some research on seals.
I can't remember if the front brake rotor seal uses a spring to tension the lip or not, so here's info on both.
With a spring, the maximum rpm limit is around 5000 rpm. Don't worry, this is just under 400 mph.
Without a spring, the rpm limit is about half that.
What this tells me is that the real world operating conditions are quite far from the design limits.

They don't give any tolerances directly for any potential "finger grooving", but they do for eccentricity between the shaft and the seal.
With a spring: .008"
Without: .005"
It would take a LOT of sanding in one spot to create that much eccentricity.

What is interesting is the surface finish. Obviously if it's too rough, the seal will wear out, so 60 grit sandpaper is out. But on the other hand, having a surface finish that is too smooth stops lubrication from getting to the sealing surface. Since measuring the surface finish is not feasable, one way to get it right is to have another part on hand to visually compare with.

[fusername]

i would use a polishing belt and do the ole towel-on-a-bum technique to get it nice and shiny quick. I just happen to have strips of old polishing belts that i pilfer from the trash at work when an edge gets caught and a belt becomes a strip. use something "coarser" to get started (think the belt is like 1200 or some such) then zip zip till im bored.

[Chris V]

It's a shame they messed up powdercoated spindles sure, but like the others say - I've cleaned up plenty of junkyard spindles and stub axles with emory cloth and haven't had an issue. The issue is having to do extra work on a 'finished' product because of a bonehead move.