drawing a spine on 01

swede2207

swede2207

Joined
Mar 10, 2002
Messages
323
Hey fellas, me again..thought i had a good question to ask..so here goes..I have a large camp style spear point blade that i just took off the milling machine and stamped. I want to differentially heat treat it. Usually i full quench in oil, then oven temper..but can i draw the spine on an 01 blade. I have heard from some this is tough to do.And to be honest if the guy who told me it was tough to do(Harvey Dean) then it must be close to impossible for a guy like me..but im going to give it a go anyway..mainly because its the only steel i have at the moment. Any suggestions??
Thanks
Luke
 
I've done it several times on large knives I've made in the past and I treated'em just like I do my 5160 and 1084; edge in a shallow pan of water and a cutting torch up and down the blade spine and body. It turned a dull blue gray just like everything else but I never "tested" one. Had I done so I might have found out what Harvey was talking about. Perhaps someone else could comment. I was down to Greg Nelley's place yesterday afternoon, had I seen this post I'd have asked him. Maybe I'll email him about this anyway. I've got a small note book on questions for him I'm keeping. I passed my Journeyman's cut and bend for him yesterday.

regards, mitch

ps, Where do you live?? I'm in Montgomery.....
 
I don't see why it won't work,either.Keeping the edge in water is a good idea.I would like to hear Greg's and Mete's opinion on this.

Just looked it up.Timkin Latrobe Steel has a great tech page on O-1. www.timkin.com ( do a google search on "O1 heat treat", and click DATA SHEET). It comments on the need to temper immediately after quench,and not to let the steel cool below 125F.My suggestion would be to quench and put straight into a preheated temper at 500,remove and draw the spine,then re-temper at 500 again.Allow the blade to cool in the oven after shut off.It recommends cryo for O-1.Probably more useful on machine parts than blades,but if available it can't hurt.
SA
 
I imagine what Harvey is alluding to is the fact that O1 has a tendency to air harden on you to a degree. It's relatively easy to unintentionally create hard spots, which of course is the exact opposite of what you're trying to do.

######

Mitch,
Congratulations on passing the performance test. You tested under Greg Neely? Good deal. I really like Greg. Helluva bladesmith. I'll bet you were nervous. Greg's a no nonsense kind of guy. He's a good one to have critique your work too. If anythings not right you WILL hear about it. :D
 
Primos and Bladsmth you have things confused. Swede, harden and double temper at 400F [ the toughness drops at 500-600] Polish the blade to get a clean surface so you can see colors , then proceed as anvilring explains. Work slowly [tempering takes time] keeping the torch always moving to get up to 800-900F.
 
mete said:
Primos and Bladsmth you have things confused. Swede, harden and double temper at 400F [ the toughness drops at 500-600] Polish the blade to get a clean surface so you can see colors , then proceed as anvilring explains. Work slowly [tempering takes time] keeping the torch always moving to get up to 800-900F.
Click to expand...

Mete, if this is so, why does Crucible show the highest toughness (Charpy) at Rc 55 - 57 and a temper of 600 degrees F? I know that Randall uses 571 F for their O1 blades.
 
I worked with Ketos (crucible O1) for years, until I switched to carpenter O1 about 2 years ago. Although you will have to temper a lot higher than other steels (184, 5160, etc...) the specs for tempering on the data sheet are a bit on the high side. I was always able to get the desired rockwell at slightly lower temps. So adjustments do need to be made, this could be due to the size and cross section. There is a slight dip in the impact strength curves in the 500+ range with Ketos but it is not bad at all when compared to other steels, since O1 really isn't designed with heavy impact purposes in mind I don't think I would sweat the issue.

Edge quenching could be an absolute disaster with O1 but drawing the spine should work (although not as effectively as other steel), I would just strongly recommend that you heat very evenly on both sides with the torch, while the edge is in the water, or it could get a little wiggley on you ;)
 
Fox, I suppose I should keep this response on file so I don't have to keep typing it out...All steels are melted to a range for each element even though the chemistry is often given as nominal.The mill may ,for a number of reasons ,melt to the high side or low side for any element. In addition for some of the tool steels like O-1 there are also optional alloying elements .So if we compare O-1 from different mills we can find sustantial differences in l the chemistry and substantial differences in heat treating and properties.
 
Thanks for all the great info, congratulations Mitch on your journeyman test! One day i hope to be where you are..Ive been using 01 exclusively for over a year now. My normal ht is heating to critical,then a touch more ..quench in oil, then place in oven at 400 for two hours..then repeat..ive never tried to do a spine draw before..do you suppose i should go ahead with it or just full quench and temper? Or should i abandon the 01 for this particular knife and try something else?I wish i had a ht oven but the knife gods havent seen fit to send one my way yet.
 
mete said:
Primos and Bladsmth you have things confused...
Click to expand...
What have I got confused?

From what I've been told many times in the last 11 years or so from numerous bladesmiths, in thin cross sections such as a knife blade, if you get sidetracked while drawing back the spine with an O/A torch and get even a little red on the spine you can actually create a hard spot. This was in reference to both O1 and 5160.

So they're all wrong?
 
Primos , so that's what you mean . My comments to go slowly and keep the torch moving [ and pay close attention] should prevent the possibility of getting it hot enough to reharden a spot.
 
I agree that you should keep the flame moving,and not heat the steel beyond 800-900.I disagree that the toughness drops at 500-600.Hardness continues to drop at that point.Toughness increases up to about 900-1000 .The intersection of the tougnness curve and the hardness curve is at 500-600 degrees.This is the optimal temper for this steel.
SA
Mete,I totaly respect your knowledge on metalurgy.You are the guru for most of us.I think you looked at the chart backwards this time,though.If I ever had a metal problem I couldn't figure out,I would ask you. - Stacy
 
I start to draw back the spine with my o/a torch making the "frying bacon" sound; it's hot! Now, pardon the caps: I HEAT EXACTLY THE SAME ON BOTH SIDES! About 4 passes on each side of the ricasso then I start up the blade toward the tip then back UP the other side; ricasso to tip, NOT tip to ricasso... I'm going slowly! with the hot blue 1/4 inch of extra hot right on the blade and moving it in small dime size circles and dipping the edge in my water pan (a 1/2 inch deep in H2O) as needed.
If there's one thing I"ve learned this past year, it's what a piss poor conductor of heat steel actually is!! From welding damascus billets to drawing, it's amazing to me how damn stingey steel is with heat conductivity! Even the guys who do a full quench to harden sometimes forget that they have to flip-flop the blade often to get it heated evenly for quenching even in the forge! The "burner side" is ALWAYS hotter... and folks wonder why things warp.

Even heat, even heat, edge'n tip in a pan'a water....

regards, mitch
 
I believe what mete and others were getting at here was this:

o1temper.jpg


There is a notable area between 400F and 500F where you will lose rockwell hardness with no real gain in impact toughness. This is what I was referring to in my earlier post when I said that it is not that bad, because with O1 it is a level area, whereas with other alloys there will be a noticeable dip in tht same range where it is actually possible to lose both hardenss and toughness. We don't see the problem much in our applications but it is known at martensite tempering embrittlement and has caused more than couple wrinkled brows among heat treaters.
 
Bladsmth, I wish you all would read my response to Fox a few times ,it's very significant.I looked at one graph, an old source, it's significantly different and there will be differences in the O-1 of each mill.Again there will be differences in the various tests for toughness, the torsion impact really shows a dip. I'm also sure there are differences in melting procedures today which again might minimize the problem of temper embrittlement. A graph of similar O-2 shows torsion impact strength of 150 ft-lbs at 400F ,70 at 500F, and 50 at 600F !!!! That's temper embrittlement .
 
What are some steels most effected and least effected by this? Are there any known alloy elements that have a noticable effect on either reducing or agrivating the embrittlement? Does carbon content play any part in it?
 
AwP said:
What are some steels most effected and least effected by this? Are there any known alloy elements that have a noticable effect on either reducing or agrivating the embrittlement? Does carbon content play any part in it?
Click to expand...
Phosphorus and moly would play a role in the prevailent theories on this problem. The carbon part I cannot say, since most of the literature I have seen on it dealt with studues of medium carbon alloys. It really isn't much to worry about unlesss you are really pushing the envelope on impact performance and ways to measure it. It is one of those things that most blade makers never have a problem with until you tell them about it.;)
 
Kevin, that chart did much to clarify this entire discussion. Can you tell us the source reference? I have been looking for a series of such charts for all of the steels I use, for quite some time now, to no avail. I would love to have that book as a reference. I am always happy to add some more "egghead" books to my collection. :D

mete, thank you for your response, and your patience. I was well aware of the differences between various melts and multiple manufacturers. But, not being a metallurgist, I guess what surprised me was that there is still such a wide disparity in heat treatments among a single steel specification.

Now, having said that, I will note that I just learned such a lesson in my own shop. I had to make an adjustment in tempering after switching from Starrett to Timken-Latrobe. Using Starrett, I could not pass the brass rod test with O1 unless I tempered at about 370 F. With Timken-Latrobe, I had to raise the temper to 400 degrees to get the same result, all other variables being the same.
 
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