Hub Cones: Resurfacing Vintage Bicycle Hub Cones

 

 If you have been restoring old bikes for a long enough time, you've undoubtedly run into at least one or two cases of pitted cones. [The basics of cup and cone hubs can be found HERE.]

Often, the cone and bearing balls will become worn or pitted first, followed eventually by the cup inside the hub shell. This presents an opportunity - if you can clean, repair, and re-pack the hub before the cup inside the hub shell goes bad, you usually can save the hub the scrap heap. 

So you need good bearing balls and good cones. Good bearing balls for the common Schwinn, Raleigh, Sturmey, etc. hubs are available on eBay, Amazon, etc. I buy mine in bags of 500. 

That leaves us with the cone - what to do with a pitted cone. If the pits are very minimal, you may be able to ignore them for now, or you may get by with a simple, gentle hand polishing with some Simichrome polish and a soft cloth.

But what if the cone needs more resurfacing? Sometimes this is easily done because the replacement parts are common, but sometimes you want to try to save the old part.

Over the past couple of days, I've set up my desktop drill press so that I can resurface old cones. The results have been very good - cones with minor and moderate pitting can be smoothed out using the drill press.

Here is the set up:

I have an scrap Sturmey Archer front axle in the chuck of the drill press, and the cone needing work threaded onto the axle. (Note - use an axle that is scrap, don't use a good one in the chuck). 

On the work platform are my supplies - a bottle of light oil, a pencil stone (as one can get for a Dremel tool), coarse sand emery, fine emery, a felt polishing tip, and Simichrome polish.

So let's begin...

With the axle in the chuck, and the cone threaded tightly onto the axle, we can now turn on the drill press and it will turn the axle and cone. This particular cone has moderate pitting, as show below. Let's give this a try because, frankly, the alternative is to throw it away anyway, so why not try to save it?

With the drill press turning our set up, we can put some oil on the stone and gently begin smoothing the bearing surface. I work in gentle, up and down strokes to cover the surface evenly and to preserve the general shape of the cone while removing material. You want to remove material gradually and evenly. Don't press too hard, and refresh the oil every so often. Stop to check your work frequently.

Once the worst of the pitting is gone (it's a judgment call), you can move to the coarse emery. Again, oil the emery a bit and gently smooth, using up and down strokes to evenly cover the surface. Don't push too hard. Let the emery and oil do the work of smoothing.

After awhile, you should have a relatively smooth surface. You've removed enough material to get rid of all but the smallest pits (they're tiny specs now). You may need several cycles of stone and coarse emery to get where you want to be for final smoothing. When you reach that point, it's time for the fine emery with a little oil on it. Your end of the work is the same: gentle pressure, and up and down strokes to evenly work the surface.

Below is the surface after the coarse emery and before the fine. You can see it's already much smoother, but there is still a little more to go...

 

And below is the surface after the fine emery. Getting there...

Having gone through the stone, coarse emery, and fine emery, we're now ready for a final polishing. This will give us the smooth, mirror-like finish we want for running the hub with the bearing balls. I take a little felt polishing tip (again, the kind you might buy for a Dremel tool), and load up the tip with some Simichrome polish. This is a high-quality metal polish that I like for cleaning up plated or smooth metal surfaces.

No to sound like a broken record, but your process is the same: gentle pressure and up-and-down strokes with the polishing tip to work the surface evenly. Below is the result.

Not bad at all... it's looking much better.

At this point you have a couple of choices. You can leave the surface "in the white", which is fine if you are going to immediately build this cone into a hub and start riding. The grease and use of the hub will prevent corrosion.

But if the cone is going into the parts drawer for later use, why not add a little rust prevention? At this point, I take a rag with some acetone on it, and de-grease the surface of the cone. With the surface clean, I apply a little cold bluing solution (Birchwood Casey brand, in this case). The bluing will bring the surface to match the rest of the cone, and we end up with a part that looks an awful lot like a new old stock cone. It might not be perfect... but it's a lot better and we've saved this cone from the scrap heap.

And the cone can then be rebuilt into a hub using the normal re-packing method.

One question you may have is whether we can do this with a Sturmey Archer AW cone. We often come across AW hubs that have pitted cones, but are otherwise in good shape. The answer is, "yes", you can absolutely resurface a Sturmey Archer AW cone with mild or moderate pitting. You'll need a donor Sturmey Axle half to put in the chuck, and then your work is basically the same as I have outlined above.

The result is pretty good:

So the bottom line is, yes, you can absolutely save your old front and rear hub cones if you have a home drill press, a few basic materials, and the patience to check your work as you go. Let's save as many of these old parts as we can.