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RKW
10-27-2009, 02:23 PM
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
10-27-2009, 02:26 PM
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/showthread.php?t=7391&highlight=drilling+a+ball+bearing

tattoomike68
10-27-2009, 05:42 PM
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. :D

HSS
10-27-2009, 06:04 PM
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
10-27-2009, 08:15 PM
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
10-27-2009, 08:24 PM
All sorts of soft steel balls,cheap even-

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

darryl
10-27-2009, 08:43 PM
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
10-27-2009, 09:36 PM
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
10-27-2009, 11:06 PM
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
10-27-2009, 11:16 PM
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.

Evan
10-28-2009, 01:15 AM
Use borax slurry in water. That's what white flux is. If you don't have it then just use water.

Jim Shaper
10-28-2009, 02:29 AM
A center cutting carbide endmill will plunge hard balls with a little resistance.

I'd just knurl or peen the mating sleeve and fore go the threading. Loctite would be another option.

Evan
10-28-2009, 08:07 AM
Here are some examples. I threw these in the wood stove in a can with water so I didn't have to clean off flux. They drill nicely and thread ok too. The ease of threading these and for that matter, anything else depends on the quality of the taps, but that is another thread.

They come out with a very nice even and thin black oxide finish which looks good enough to leave after a touch on the buffer. Buff a little longer and they are back to shiny.

One use for them is the ball joint shown here. I have some thick wall SS tube so I opened the inside just enough to fit the bearing and turned down the outside to about .020 wall thickness. The bearing is drilled and tapped to 1/4-20 and a stub of a bolt wound in until it bottoms good and hard. The fitting is a connector nut turned down at the bearing end to give clearance to the socket. The lip of the socket is spun down in the lathe with a blunt carbide tool. I tested one to destruction and it took several hundreds of pounds force to pull it out. Even levering it past maximum freedom angle it was nearly impossible to remove because the SS work hardened as it was spun down.

It has a little rattle space because of the springback of the SS. If that were an issue a neoprene or PTFE washer on the seat would take care of that.

http://ixian.ca/pics6/ballb.jpg

S_J_H
10-28-2009, 08:26 AM
perhaps the balls I have used were not that hard, but I have only needed to torch them to a redhot for a minute or so and let them air cool on a brick. Then I have had no problem drilling them and have done this many times.

Steve

Black_Moons
10-28-2009, 05:43 PM
Awsome evan, spining thinwalls down with blunt carbide tooling? Ingenious. I allways wanted to try a little metal spining on my lathe but was worryed about stresses to do large projects like bowls and such (be fun to maybe adapt a cheap wood lathe or make your own metal spining lathe..) but this is perfict.

Any details on the spining tool? like did you put a small radius on the top to blunt it?

Evan
10-28-2009, 07:27 PM
I have a supply of large sticks of solid micrograin carbide. I use it in my shaper for burnishing and for that I put a gentle radius on the end of the stick. The sticks are about .5 x .25 x 2". I just used one of the burnishing tools to spin down the SS. It works slick and would probably work just fine with good HSS tooling too as long as it is lubricated with a little hypoid extreme pressure lube. That is something I found when burnishing steel is that extreme pressure lube isn't just an advertising gimmick. It really does hold up under extreme pressure compared to other type of oils and greases.