Anybody ever use S7 steel?

G

Gossman Knives

Edged Toolmaker
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Apr 9, 2004
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All these questions. Well I'm on 2 weeks vacation so I've got some time for the forums.:D I think Kit said he has used S7 before. I want to try it out and was curious if any of you guys have worked with it? The HTing sounds easy enough for my equipment and I've heard alot of good things about it for an outdoor use blade. Just looking for opinions and comments about it. Thanks
Scott
 
I normally use A2 but have used S7 when making tools that will be sharpened with a file, since it gets soft enough. (At 1000° A2 is about 55 HRC while S7 is down around 50 HRC; much easier to file.)

The stuff is beastly tough. I work with folks who used to make jackhammer bits out of it. It's not as abrasion-resistant as A2, seems to grind easier. HT isn't too hard with a furnace, and plate-quenching works good. (See Crucible's Data Sheet for HT info.) My understanding is that it's ideal for big choppers - things that will see a lot of abuse.

-Allin
 
A2 peaks in impact strenght at HRC 60 and at ~HRC 57. At 57 the edge is easier to roll, so I use it a 60 even on choppers. Harden at 1750°-1780°F, plate or oil quench, cold treat and temper twice at ~425°F.
 
I have not myself made a blade of it but did HT a rather large chopper for another maker. Without looking up my notes, I am thinking I hit it at about 57 -58 HRc. The maker reported he was extremely pleased with the S7 blade. It is supposed to be some EXTRA tough stuff (S7) and would probably lend itself VERY well as a chopper.

RL
 
I finished up the S7 blade yesterday and HTed it today. I did some cutting and chopping with it and I like the way it performed. The blade is 3/16" thick and 6" long with a 4 1/2" handle. I haven't finished it yet. The edge held up pretty good and was easy to resharpen. I gave it a moderate workout. When I get it finished up with handles I'll be able to put it to more hard use. It was about like A2 to grind, not bad. I think it will be a good steel to start working with.:)
Scott
 
Scott,
I certainly hope you keep us updated on how it works for ya. I'd love to know how it performs on hard impacts. The numbers from the scientists say it should be tougher than just about anything else out there, but I'm extremely curious to hear how that translates to hard use in a knife.
 
It was my knife Roger heat treated (thanks Roger). I have become a big fan of S7 and have bought a couple of knives from other makers in it. Not the most wear resistant stuff in the world but hard to beat toughness wise. Very good impact resistance even if you run a fairly thin edge. If you like 5160 in a knife then you should be very pleased with S7.
 
Mark Nelson said:
It was my knife Roger heat treated (thanks Roger). I have become a big fan of S7 and have bought a couple of knives from other makers in it. Not the most wear resistant stuff in the world but hard to beat toughness wise. Very good impact resistance even if you run a fairly thin edge. If you like 5160 in a knife then you should be very pleased with S7.
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Mark that was my feelings about the S7, quite similar to 5160. HTing was practically the same as A2.
possum, I did some chopping and hard stabs twisting and turning the point with no problems. The edge held up with no deforming (rolling or chipping) in hard wood (treated lumber). It's hard to get a good grip with no handle scales. I can get into more serious tests when it's finished.
Scott
 
Have used S7 many times before and it makes a fantastic hard use blade.
Tricks I have found:
Water quench it in hot super quench and do an interupted temper.
Half way thru the temper cycle dip it in water, do this twice.
Use a convex edge
It has Vanaduim SO WEAR A GOOD MASK!
Then go beat the hell out of it:D
 
Is super quench the quenching medium by Texaco or the water, salt, dawn detergent, Shaklee product? Thanks. If it is the water mixture ... I thought that it was not to be used on high carbon steel?
 
Anyone have any opinions on how L6 would compare to D2 on edge retention?
I made a knife out of an old cross cut saw, which is supposed to have been
L6, many years ago. I remember it was a good knife, but I don't know where it is right now. Thanks for any opinions.
 
Here's a pic of the S7 test knife. Curly maple scales, convex grind, N/S pins and brass lined lanyard hole.
Scott

cms7.JPG
 
Lookin' good, Scott. I'm a fan of convex grinds. I always have trouble with my big blade hitting things it's not supposed to, like concrete and scrap iron. I don't think I've ever had to sharpen my big bowie 'cause it got dull; I have to remove all the nicks and edge damage before wear resistance comes into play. If you'd be inclined to do some severely abusive testing on such materials, I'd eagerly read it. I can even mail you a live raccoon for some real authenticity. :D :D

If ya don't mind my asking, what hardness/heat treating methods are you using? Do you know of someplace that sells it in barstock conveniently sized for stock removal guys, or do you have to forge it down from thicker material?
 
Razorback - Knives said:
possum, that's where I get mine.:) I heat it to full color, run a soak for 30 minutes and quench in 130 to 140 degrees trans fluid. I temper it for two 2 hour cycles at 390 degrees. I don't have a rockwell tester but it should be around 57/58 rc.
Scott
Click to expand...

Like the knife a lot Scott. At 57/58 you should be able to drop a bomb on it without much effect. Make sure to let us know what you think of S7.
 
Thanks for the links fellas. Much appreciated.

Won't have enough spare cash to buy any materials for a year, but I'll bookmark those sites for later.
 
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