S7 for a hardcore chopper?

A lot fo the cutting comp knives are made from CPM M4. There are some smiths who use S7 for things like tomahawks. As for working with aeither by hand, probably not a good idea. :eek:I don't know about S7, but Gayle Bradley told me that if you work with M4, you had better like the finish that you have on it before you heat treat the stuff because hand sanding it in a hardened state is out of the question.
 
jdm61 said:
A lot fo the cutting comp knives are made from CPM M4. There are some smiths who use S7 for things like tomahawks. As for working with aeither by hand, probably not a good idea. :eek:I don't know about S7, but Gayle Bradley told me that if you work with M4, you had better like the finish that you have on it before you heat treat the stuff because hand sanding it in a hardened state is out of the question.
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2nd that
CPMm4 AND CPM10V AND CPMS125V all i like to have hand sanded before heat just so all i have to do is clean up after heat treat
S7 should not be that bad but im not sure how it forges
 
I think the main problem with S7 is a lack of abrasion resistance. S7 is a shock resistant steel so it is made to take impacts but not hold an edge. CPM3v was made to compete with S7 in tools that need high toughness but also need to hold an edge. I don't think S7 would be all that great for a knife but I've never tried it. I'd love to hear from anyone that has.
 
got to say
the steel i like working with
cpm3v for carbon high allow
cpm154 for SS

and for now 1084m ( V added ) or 52100
i work with many more but have got the most use out of those


now all that said im a stock remover not forger and your fave steel could be vastly different
 
ya s7 has really low edge retention but killer impact strength but man cpm-3v is the king of both
 
AcridSaint said:
With the other options out there, I'd not use S7 for anything knife related.
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Scrap Yard does. They call it SR-77, but it’s S7 with the Busse heat treat. It keeps the toughness but produces a decent edge. Granted, SR-77 doesn’t hold an edge as well as the Swamp Rat knives do, or Busse INFI. But it’s good enough that many people use those knives in the field and praise them. As for choppers, try out either version of the Dogfather.
 
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S7 is limited only by the fact it maxes out at about 57 HRC when heat treated properly. It is very impact resistant, which is why it is in the shock resisting family of alloys. The grade has almost no carbide volume in it's structure so it's abrasion resistance is low. On the plus side, if you are considering using files to shape the blade S7 is not hard to work with like the carbide containing materials like M4, 3V etc. Would it make an acceptable chopping knife? Yes, but you would sharpen it more than others, made from a little higher grade materials. Give it a run and see what you think.
 
s7 ... why not ( i have no experience with it.. )

has their been any testing where a cpm whatever steel has out shined s7... or is this just going by company generated stat's:rolleyes:

for a chopper.... i'd go with several steels.. but keep in mind what your cutting for the geometry and grind..

O1,L6,W1,1084, 5160,and possibly A2

Greg;)
 
thanks guys i was just curious i had read a little about S-7 and that it was used for dies and axes and hawks and was just curious.

i'm just a newbie but as i read all these posts and other stuff i really am kind of starting to figure out that picking the right steel for the right project is important and to that end I am trying get things figured out.

thanks

jake
 
LongRifle here on the forum has some CPM3V for sale, if you're interested. I bought a chunk from him and got it quickly. :thumbup: Haven't done anything with it yet... I'm almost afraid to try and cut the stuff with my cheapo hacksaw... :o
 
I think the main problem with S7 is a lack of abrasion resistance. S7 is a shock resistant steel so it is made to take impacts but not hold an edge.
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ya s7 has really low edge retention but killer impact strength
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The grade has almost no carbide volume in it's structure so it's abrasion resistance is low. ...Would it make an acceptable chopping knife? Yes, but you would sharpen it more than others, made from a little higher grade materials.
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I find myself wondering why we equate abrasion resistance to "edge holding", especially when discussing a "hardcore chopper". I could see abrasion resistance as a serious concern if we were talking about a hard core rope cutter, or carpet cutter or something. But for chopping, the main things I'm personally looking for are hardness, for strength, which prevents the edge from rolling and denting, and impact resistance, which will prevent chipping at that relatively high hardness.

Abrasion resistance really isn't a concern for my chopping knives, since they generally don't get dull via abrasive wear. I always seem to manage to hit one stray piece of something that puts a ding in the edge first. So I have to sharpen out damage long before the edge loses its bite. And even if it does get slightly dull from chopping dirty wood or something, we're talking about taking 6 seconds to give it two swipes per side on a diamond rod, and we're back in business. As opposed to spending 15 minutes with a coarse stone to remove that big nick from accidentally hitting a rock or nail.

Lots of simple carbon steels don't have abundant carbides, such as 1080 which is often mentioned around here. A blade in the upper 50's Rc can still do a lot of work without carbides. Anyone remember that time Cliff Stamp took a cheap hardware store hatchet, and made over a thousand chops into wood before it refused to take hair off his arm? Yeah, I know the mention of that name will cause eyes to roll, but even though I haven't tried to replicate that test it seems to agree with what I've noticed in my own use.

I'm not trying to argue against steels like CPM-3V here; far from it. I'd like to try some myself for blades that will see a mix of normal cutting and chopping. But for a chopper, I don't see how wear resistance will really help, especially when it comes time to sharpen out nasty damage.
 
If impact resistance is the key attraction to S7 for a chopper, then one would assume that edge deformation would be less likely and abrasion resistance would come into play. Folks can use whatever they want, but I'm still going to say I'd rather use one of many other high quality steels out there over S7.
 
AcridSaint said:
If impact resistance is the key attraction to S7 for a chopper, then one would assume that edge deformation would be less likely and abrasion resistance would come into play.
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I have yet to meet the steel that will keep a pristine hair-popping edge after chopping into a rock. Even if the damage is lessened by using a tough steel, it will still need to be touched up in that section, again, usually long before wear resistance comes into play (at least for my use anyway).

Actually, I'm more intrigued by S5 as it is. At least on paper, it should be tougher than S7 at even greater hardness.
 
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