52100 bearing races,no good for forging?

B

blackboogers

Joined
Jan 16, 2002
Messages
219
I am in the process of making my forge. In my place of work I get many hundreds of pounds of basically like new SKF bearings. I had our SKF rep. in our shop not to long ago to do a bearing failure analysis. He said all SKF bearings are 52100 material. That said I have bearings races that measure from 12" od down to 4" od, the widths vary from 1.5" to 4.5" and thickness any where from 3/8 to 1/2. My primary queston is this, I've been told that the material cannot be used for knives as it has a memory and will warp (If I understood correctly) when heat treated back to the original curve of the bearing race. If I heat to forging temp (according to manf.) at around 2000 deg. and press flat in my 100 ton press, equalize and normalize,anneal etc. Is this material going to warp the original machined shape? It seems to me that the grain orientation will be struck new upon forging. Sorry about the long post, I have saved about 300# of bearings and I'm wondering if I have wasted my time. Anyhow, anybody with some knowledge by all means post away.
 
I've forged a few blades from 52100 bearing races that were approx. 6" diameter by 3/4" wide by 1/4" thick, and they straightened out fine and behaved themselves. I did a "Fowler" heat treat, and never did get them over 1700 degrees, so I would think yours would behave in a similar fashion, my best guess. Why not give one a whirl and see for yourself?
 
I have forged lots of bearing races into knives and never had one even think about taking on its original shape. As long as you know for sure that you have 52100 bearing races (not all bearing races are of 52100), you are all set. Tom Lewis
 
I have made a lot of knives from SKF bearing races and never had more warping problems than with other steels. If they warped during heat treating, i did something wrong before that. Over here in Europe, SKF uses only the best Uddeholm 1.3505 steel for their races. This is the same steel you call 52100 in the USA.

Achim
 
BB,

That rep. was right. The other day I forged a knife out of a ball bearing, taking the normal steps of triple normalize and triple anneal. I then carefully ground out the most beautiful blade that I have ever made. I mean to tell you this blade had the beauty of Lauren Bacalls' lips forged right into the blade. No ****. Any way on the first quench I carefully heated the edge to critcal being very careful to keep the heat even from side to side and not get the spine hot enough to harden. I slowly quenched the blade to the proper depth and when the color was gone from the back submersed the entire blade into the oil. PERFECTION. I went out yesterday morning to pull my beautiful lady from the quench and all there was, was a round ball of steel in the tank. Yeh the damn thing had a memory and reverted back into A DAMNED BALL BEARING.:D :D :D

So you had better box up all that Junk that you have saved and send them all to me. I won't charge you anything to dispose of them PROPERLY but you will have to pay the shipping.;)


Bill
 
Well here it boys, does anybody want to do some trading. If you have good stuff to trade, the cut and cleaned bearings is what you will get. You can see they are big and wide,about .375 or thicker in some spots. I get the box you see filled in about 2 months. All SKF,all 52100. I have our SKF rep. in here about 3 times a year and he says its all 52100. I prefer handle material or will give you a very large amount for a damascus billet. See pictures here at http://hvknives.homestead.com/knifeconstruction.html
 
p.s. I knew the material would be excellent for forging and knives. Somebody told me that the steel has a memory and will warp when treated. I didnt understand because I knew when you forged it you will realign the grain structure. I'm saving it for me until my forge is built but until then its just metal in a box and I can get many hundreds of pounds in the mean time.
 
I am the one guilty of saying this about the memory. I had a single bad experience with the races, asked a couple of mastersmiths that I trust, and simply was repeating what they told me. Metallurgically I know it doesn't make sense--in theory good thermal cycling should erase that memory. Oh well, I hope everyone has better luck than I did.

John Frankl
 
No reason to be guilty John, I just really felt this would be good material for knives. 52100 is really not available in bar stock (at least not yet) so I had hoped I would have a great resource. I just needed some other input. When I get my forge built I will send you a billet to play with. Best Regards,Hurl.
 
I admit to giving up after one try to forge bearing races. It crumbled on me, I don't know if I was forging too hot or, as is my usual problem, continuing after it cooled too much. I'll get past 5160 one day.
Still trying, Lynn
 
we have found that properly normalized and annealed 52100 will warp during hardening if care is not taken to heat both sides evenly. It dosen't seem to matter that the temp is even but the time at temp has to be even also or the blade will curve to the side that was at temp the longest. I would think that in a coal forge the heat would be the same on both sides of the blade but in a gas forge with the flame blowing in from the side one side of the blades is subjected to more heat than the other. This will cause a warp in the blade especially the thinner ones.
 
Bill,
Thanks for that info. How do you get around that particular problem? Also, despite your funny reply above, do you think races are a good source for 52100? And how would they compare to 2.75" ball bearings?

Thanks,

John
 
John,

The experiments that Ed and I have done have shown us that the more forging that takes place, in the form of cross sectional reduction the better the performance of the finished knife. So based on this I would have to say that it would not matter whether a blade was made out of a bearing or a race but how much forging, at the proper (low) temp was done to arrive at the finished blade. All coupled with proven heat treating methods. BUT I personaly feel that any knife made from 52100 has the potential to be a great knife.

I use a acetylene torch to heat my blade and take special care to alternate from one side to the other during heating.
 
Thanks Bill. So, to avoid warpage, it is not all of the forging, normalizing, annealing heats that have to be perfectly even, but the final three heats prior to the final three quenches? Because I use a Mankel's knifemaker gas forge and, sure enough, the burners all come in on one side. It would be tricky to keep things even all the way.

John
 
I called Fry, they do not carry 52100 in flat stock as the same with Admiral. They both have the 3/4 rounds. Fry is $4.59 a pound with a 18# min. I've done alot of searching for flat stock for 52100 in knife blade sizes, maybe somebody gave you bad info.
 
I have an old catalog. Although, most people I know, that forge, prefer the round stock. Go figure.:confused:
 
I usually don't have much of a problem with evenly heating single edged blades in my gas forge, I just point the spine at the burner. The edge still heats up faster because of the smaller cross section, but any time I've had warpage, it's been attributable to some other error. Double edged blades I kind of spin, but I haven't had such good luck with them lately.
 
You must log in or register to reply here.
Back
Top