Drilling Holes In Ball Bearings

[RKW]

I need to drill some 1/4" holes in some 1/2" high carbon steel balls. They are stated to be 60-67c hardness but I cannot find anything softer. I do not have any carbide drills only HSS and wondered if I needed to anneal them first. For that matter I also wonder if they are hardened throughout or just case hardened.

I plan on using a pot chuck to hold these in the three-jaw on the lathe ...

What have others done?

[RKW]

Geesh, I hate to answer my own post but after searching a second time with new criteria this older link showed up ...

http://bbs.homeshopmachinist.net/sho...a+ball+bearing

[tattoomike68]

Turning a ball by hand and eyeball is not hard, get it close and then grab a file. we dont need any stinking ball turning attachment.

[HSS]

I needed to drill a 5/32 hole thru a 3/4" bb. I got a 1-1/2" X 2" nipple and 2 caps. screwed 1 cap on one end dropped the bb into the nipple along with a strip of paper, screwed cap onto other end and hung the thing from my vice with a piece of wire. I then heated the whole thing cherry red with OA torch. I left it hanging on the wire until the next day, then drilled the hole. It was still tough to drill but not impossible.

Patrick

[Axlemoron]

I think you can get unharden balls from a place like Salem Ball Co. Do you want them to be hard after you are done?

EDM was my first thought.

[wierdscience]

All sorts of soft steel balls,cheap even-

http://www.greenbaymfgco.com/catalog.php?cat=6

[darryl]

Visit a dollar store. There are some toys that have a number of steel balls as part of it. Usually it's a magnetic sticks type of thing. Those balls are soft- I've drilled and tapped several without problems.

I've also drilled ball bearing balls, after heating and slow cooling. It's still a tough steel, but doable as others have said.

[Evan]

The key to annealing bearing balls is very, very slow cooling. That steel is air hardening so the cooling rate must be less than 100 degrees per hour or even slower. The best bet is in a well stoked wood burning stove or a big pile of BBQ charcoal. Put the bearings in a small steel box or can with some water and wire it shut with some tie wire. Make sure the steam can escape. It will displace all the air and the fumes that are drawn back in won't have much if any oxygen so the bearings won't build much of an oxide layer.

[RKW]

In a previous post you mentioned borax rather than water. Is one better than the other?

The key to annealing bearing balls is very, very slow cooling. That steel is air hardening so the cooling rate must be less than 100 degrees per hour or even slower. The best bet is in a well stoked wood burning stove or a big pile of BBQ charcoal. Put the bearings in a small steel box or can with some water and wire it shut with some tie wire. Make sure the steam can escape. It will displace all the air and the fumes that are drawn back in won't have much if any oxygen so the bearings won't build much of an oxide layer.

[tattoomike68]

A good old cheap steel bucket full of wood ashes works real well. get the parts hot and drop them in the ash and cover. big parts will still be hot the next day but not too bad.

Its cheap and works like a champ.