Rehabbing bicycle bearing cone?

Argonavis

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Hello,

I have the bearing cone for a bicycle wheel hub with a shallow imperfection directly in the bearing ball path. I'm guessing the surface could be restored by removing perhaps .01" worth of material, however I've never tried this and am curious to know if it's likely to be successful. I could make a HSS form tool to match the curvature of the cone, but I suspect that may not be a viable approach since the cone is hardened. Would it be better to try a carbide insert, or possibly jig up a die grinder of some sort?

The other issue is that I'm completely in the dark about whether the cone is through-hardened, or whether there's any risk of skimming off the hardened surface and thereby ruining its utility in the bearing?

Or... am I just tilting at windmills? :)

Thanks for any insights,

Hannes.
 
Bearings are hardened, then ground. HSS most likely prove to be a lesson in futility.

"Billy G"
 
Pretty sure it's through hardened. From your description, I wouldn't worry too much about destroying it. I think a die grinder is the only option.
 
are the cones not removable? someone put them in the hub ? are the ends of the hub rolled over the end of the cone to keep it secured ? then again a new hub assembly may be a necessity and a test of re-spokeing a wheel :) just sayin'
 
are the cones not removable? someone put them in the hub ? are the ends of the hub rolled over the end of the cone to keep it secured ? then again a new hub assembly may be a necessity and a test of re-spokeing a wheel

I take your point. And yes, they are very much removable.

However, I generally try to reuse and rehab components when reasonable, particularly when the flaws in a part are relatively minor and can be remediated with no loss in function. The alternative strikes me as being rather wasteful -- and I freely grant that this perspective is rather at odds with the current paradigms in our society. There is also the issue of cost, in that a new cone may cost around $10 with shipping, and it doesn't take too long before such replacements exceed the cost of the hub (read this sentence to the Johnny Cash tune "One Piece at a Time" :).

:) just sayin'

I know. :) But I like my windmills.

Hannes.
 
#! The cup and cone must match.

#2 the surface the ball or roller moves on has to be smooth as a babys' bottom.

You will need to cut both the cup and cone to match the oversized ball. As said, most bearings are thru hardened. You will not be able to use the same balls or rollers due to the race size change.

If it were me doing this, I would opt to replace the parts. It is the easiest way out.

"Billy G"
 
Your question is about how to machine bearing races and if you find a way to recondition the cones then please let us know. Bike dealers (Specialized) have told me that the whole hub has to be replaced since they can't get just the cones. Even if they could get the parts it might require special tools (that they don't have) to press the races out and back in properly. Anyways like you say maybe just the axle and bearings seperately are worth more than a hub assembly.

I miss the good old days when we could buy parts and fix stuff although I can't say that I miss points and condensors.
 
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If I read this correctly (and I sometimes don't), the current bearing and cone (and possibly hub) are at "junque" status unless repaired. I would tend to lean toward the die grinder (Dremel?) approach and carefully/lightly regrinding the surface. A .001" surface correction isn't very much, and if you use a very fine grindstone and profile it to match the curvature of the bearing, it could work. If it doesn't work, it doesn't seem like you're out anything since it needed to be replaced anyway. If it works, it's a small victory in one of those "they said it couldn't be done" stories. Best of luck!

GG
 
Just a thought but what if you leave the cones as is and just replace the ball bearings for the next largest or smallest size? The balls would ride in a different spot in the cone (hopefully off the 'imperfection'). It doesn't seem like any DIY machining of the cones, no matter how well it is done, will make the bearings serviceable. So new balls with waterproof grease might be enough to get you by.
 
Years ago,I re machined the built in races where the ball bearings ran,in an English bike,in the front wheel hub. They were so bad,there were "blurry",and deep indentations all around that looked like the balls had been pressed into the steel.

I was able to machine the steel quite reluctantly,on the cutter's part (!) with a HSS forming tool,but was not getting the results that were really needed. Plus,a considerable amount of steel had to be removed. No doubt led to big problems in not fitting any more. My English friend(who owned the English bike) finally managed to find NOS parts. He rides the bike to work several miles every day.

Bad as the bearings had gotten,I was surprised that the bike could be ridden at all.
 
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