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Annealing small bearing balls

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doubleboost:
Hi
Jim
I kept mine at a hot red for about 15 minutes then left them in the furnace overnite to cool.
Charcoal would be fine with a blower (hair dryer would do).
I was woried about it damaging the threads but they cleaned up ok with a good quality tap.
The material was still tough but at least a file marked it  :D :D :D :D
The slower you can cool things the better
If you are stuck post them up to me and i will happily soften them for you
John

JimM:
Guys, thanks for the extra info and the offer of help.

I've actually just picked up an old butane bottle which I'm hoping to convert into a wood burning patio heater so hopefully I'll be able to get some decent heat in that and that will sort me.

Cheers

Jim
 

airstream:

--- Quote from: cidrontmg on January 02, 2011, 01:38:41 PM ---Itīs the season to heat the house/shop (in the northern hemisphere, that is. On the other side, wait 6 months before trying this...), and for me, also the season to anneal bearing balls. I use (and have used) them for things such as machine ball handles, governor weights, Newtonīs cradles (where I usually harden them again after drilling and tapping a hole in them), and for "ornaments" in bar ends. Contrary to some beliefs, it is quite possible to anneal bearing balls so that they can be drilled (or otherwise machined on) with "usual" HSS tools. The important thing is to maintain the (red) heat for quite some time, and then let them cool very slowly. Slowly meaning at least some hours before you can pick a 20 mm ball up without burning your fingers.
You can put the balls in a metal box (so they wonīt roll all over the place. An empty sardine or corned beef tin, for example), and heat the box to red. Then you cover the box with hot sand, or ashes, or make an enclosure around it of firebricks so that it is all encased, and will not cool in a snap. I usually put the box in a (wood) fireplace, let the fire burn to embers, and after a few hours, try to drill one ball, or use a file on it. If it isnīt soft enough, it has cooled too quickly, and you have to renew the process, and make the cooling time longer. The balls are air hardening.
This works usually fine with largish balls, meaning some 10 mm and up. But small balls (~6 mm and smaller) have a tendency to cool a lot faster, because of their smaller heat capacity, and relatively larger surface area in comparison to their mass. And they are likely to remain hard (or rather, harden again). One way to prevent this from happening is, to get a biggish metal block (something like 25x25x25 mm at least, of steel, cast iron, brass, copper, but NOT aluminium, tin or lead, obviously...), then drill some deep holes on the block, over halfway down, slightly bigger than the balls, and put the balls in there. The metal block will not cool too readily, neither will the balls near the center inside it.
The balls emerge from this treatment quite black and covered with scale. They can be polished again to a high lustre, but not quite as bright as they were before annealing, so donīt even try.  :poke:
 :wave:

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why bother going to the trouble of softening ball bearings, when you can buy balls that are soft already, bought loads, also stainless ones are readily available that can be drilled and tapped.

ive softened ball bearings and spring steel in the past, by putting them in the woodburner getting them red hot and them letting them cool overnight really slow in the ashes, always seems to works for me anyway.

Bogstandard:

--- Quote ---why bother going to the trouble of softening ball bearings
--- End quote ---

Because we can.

There are times you won't be able to get exactly what you want in the softened variety, at times like that, you do it yourself.

It is like everything else we do on here, most probably a lot of it is available, but it is personal choice as to what we do.

BTW, I regularly soften my own balls, I find it is rather enjoyable.


Bogs

Blade:

--- Quote ---BTW, I regularly soften my own balls, I find it is rather enjoyable.


--- End quote ---
Be carefefull, I have heard of balls exploding if not softened properly  :lol:.

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