etherhuffer 

Found a spindle in size I needed, but you can see its forged but not polished. Old one adjacent for comparison.

Can I just chuck this my friends lathe and polish with 800-1500 grit paper? You can feel the difference in smoothness between the polished and non polished

ign1te

It will wear in. After some use the smoothness will be similar to the polished one. Roughness that can be felt by hand is usually not noticable while actually in use anyway.

Andrew R Stewart 

Back in the day the few anal of us would take apart their "cheap 10-speed" hubs and repack them with grinding compound (think grease w/ grit). Then we would spin the axle w/ a hand drill while we watched 1970s TV. After a bit the hubs would get cleaned and properly greased, with fresh balls now running on a polished track. Made your Normandy Sports roll as nice as Campy NR. Andy

70sSanO

I’d be inclined to get a dowel to match the radius of the spindle. I’m not sure you can pinpoint the exact location where the balls will be running on the cone surface. You’ll also want to apply even pressure.

I’m not sure if wet-n-dry or crocus cloth is better. Wrapping the dowel with whatever you use might give a more even result.

John

HillRider

Get a bearing retainer filled with the correct size balls and, using valve grinding or similar mild abrasives, hold it against the bearing track while rotating the spindle in the lathe. That way the bearings will polish the correct track locations.

dedhed

And I'll assume throw those bearings away and use new ones to install?

Iride01 

The bearings only contact a tiny part of that race on the spindle. Putting it in the lathe and using sandpaper no matter how fine might just make the low parts lower faster than it does the high parts. So then you'll be slightly ovalized.

If you want to do something, do as Andrew R Stewart said. I knew a guy that did that to the gears with valve lapping compound in a large deep sea fishing reel and it was the smoothest running fishing reel I ever felt.

Though personally, I wouldn't worry about it for the BB spindle. I think it'll take care of itself in a very short time.

KerryIrons

Yes, and trumpet players would put toothpaste in their valves and work them up and down for smoother action. The only issue was that the hardness of the old Normandy hub cones was such that even polished to perfection, they still wore out quickly.

Bill Kapaun

Forging & polishing are not mutually exclusive.
What you mean to say is the new one has an oxide coating or is "unpolished".

IF it's a cheap one, it's probably relatively soft and will wear quickly.

Home polishing will likely just remove the surface hardening, if any.

etherhuffer 

correct. Finding a good spindle is harder than it looks. Most are basic quality at best

Germany_chris

Are they the same taper?

HillRider

Sure. If you do a lot of this sort of thing you can save a few cents by using Grade 200 or 300 bearings for the polishing step.

jccaclimber

I’m also in the camp of using a polishing compound on the lathe if you insist on doing something to it. You could just put it in a bike frame and do it there too, spinning the spindle with a hand drill. That way you know it’s square.

Your buddy with the lathe should know this, but keep the polishing compound that will likely migrate off of the bed ways.

Yes, replace the bearings after, and make sure to get all of the compound cleaned off.

You could also just ride it, adjust the bearings as needed, and go on.

I would not try using sandpaper or re-cutting the bearing track in the lathe with a tool.

It should be noted that bearing races should be a slightly larger radius than the balls that ride on them, so it’s never going to be perfect with the correct ball size and abrasive compound. Don’t try to polish until the entire area is shiny or you’ll have changed the raceway curvature.

RGMN

ign1te

Just go ahead a buy a real bottom bracket instead. There are very few that still make cup and cone, but TANGE is one of them.

https://www.interlocracing.com/shop/...bottom+bracket

Regrease that one regularly and for gods sake use loose balls and not a retainer ring. That way you will have a rock solid component for a very long time.

etherhuffer 

I saw those. Really nice looking units. This bike won't be ridden that much, was trying to just keep the original look. I grabbed a sealed unit too. Was looking at various sealed bottom brackets, was surprised to see that these are just a case with a sealed bearing on each side. Easy to replace the bearings, but not really cheaper than getting a new one if you use a good Natchi or SKF bearing set.

etherhuffer 

Yes, I have some here. Good stuff. Really nice on chrome, brass bell, etc.

Numerozero

Why Polish? Is there a boycott on Ukranian bottom brackets?

hotbike

Yikes! Campy and JIS are different. Found out the hard way…

soyabean

Absolutely do not do this, or you'll be buying another axle.

The finish is nothing other than paint or gun metal, depending on how it was manufactured.

Bearings are much harder than the axle which in comparison is a softer metal.

When you service bottom brackets, you will always see a track grooved by the bearings.

That is expected as your bearings break-in and seat from normal use.

etherhuffer 

Another question, I found an old Shimano 5-Dll 70/119 spindle in my pile of junk. Can you put a 70mm spec spindle in 68mm cups? The races look to be a few mm more outboard than the 68mm spec spindles

alcjphil

I had a similar reaction when I saw the title of this thread. My didn't realize at first that the OP wasn't asking about a bottom bracket made in Poland. Sorry if I digress from the original purpose of the discussion.

JohnDThompson 

Yes, but the chainline may not be ideal. You'll have more thread exposed on the adjustable cup, and may need a spacer on the fixed cup to tweak the chainline.

Steelman54 

I would just install it and run it and let it wear in that is easy and you won't mess up a good spindle. you could spend a fair amount of time polishing to make it look better and not realize any gain. Of course, maybe buying a better spindle is the way to go depending on what you are building.

Road Fan

If possible, one of the safest things to do is to search for a NOS spindle and cup set which matches the original. Has that been ruled out or have you not even looked down that rabbit hole? Sometimes that is not as hard as one might think. Then it is not better than original, but it is what the OEM thought was sound. Assuming the original designers had their heads on straight, that should be a very good set of parts, long-lasting if serviced properly. An example of this kind of quality is the early 1950's Raleighs. No shop was perfect, but what I see in my 1952 Rudge frame, built at Nottingham is very good - not many flaws.

Sometimes you get a bike to work on which did not originally come from a smart designer who had a smart and competent factory. I'm just climbing out of what I hope is my last such rabbit hole!