Basic questions about steels

scdub

scdub

Dealer / Materials Provider
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May 29, 2004
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Hi All,

I'm about to start my second knife. I never quite finished the first one, so maybe this will really be my first - in any case...

I want to make a knife for personal boot carry in my new job as a Peace Officer. I will be grinding the knife to shape (I'll be forging someday!) I want the knife to be extremely heavy duty, and able to be used as a pry bar during emergencies such as traffic collisions. It will be short (~3" blade) and stout (1/4" thick).

My questions are: 1) What would you (the experts) recommend as a steel. 2) Where would you suggest I buy it? 3) How/where would you suggest I heat treat the blade? (I will be sending it to an outside party).

I want something that will be tough enough that I would be able to wedge this knife in a car door and use all of my weight on it (220lbs) without fear of it breaking. The steel doesn't need to be stainless but I would prefer something that is reasonably corrosion resistant.

Lastly, I know that some knife people don't like the idea of using a knife as a pry bar. I understand this point of view. I will in fact be carrying a quality folding knife for 99% of cutting tasks, and will have an actual pry bar in my vehicle for most of my prying needs. My point here is this - if you feel the need to talk me out of my basic design concept, please refrain. I'm not looking for arguements, just advice.

Thanks in advance.

SCDUB
 
If you want to load up a 3 inch blade with 220 pounds cantalevered out on the end of the handle, go with thicker than 1/4 steel high carbon plain steel. I only know 10XX steels so I can't help much on that part.

Well you could use 1008 and she wouldn't break. ;)
 
This might be an interesting thread to watch. I would've thought maybe a heavy piece of 10XX heat treated to about 50 - 54 HRc. I don't know.

RL
 
That will be a hard combo to get,try these choices:
Try S7 or 3V or go for CPM Rex M2
The Rex M2 is super tough and wear resistant.
You can get them from Crucible Steel.Look at the knife steel specs to compare to other steels.
Since these are non-stainless,I suggest you coat the blade with teflon,parkerize it, or some sort of coating.Brownell's has a whole line of coatings.
Paul Bos can do the HT for you.
Make the blade with chisel tip.Add a little skew to the point ( like a tanto).
1/4" is enough to hold up ,5/16" might be a little better.Put in a little distal taper,but not much,maybe to 3/16 at the tip bevel.
Black canvas micarta handle would work well.Corby rivets.
 
I would go with s-7, theres not a steel that not much tougher. to give you an idea of how tough it is, the most common use is for jackhammer bits. 1/4" is thick enough. You might have to sharpen it a little more often it a little more often, but with a decent butcap you could hammer and pry all you wish.
Del
www.ealyknives.com
 
This advice isn't from me as a maker, but rather as a user. My DACOR dive knife was designed specifically for prying. The tip is actually shaped more like a broad screwdriver than a point of any sort. The steel is 440A and though it wouldn't hold an edge too long, it is extremely rust resistant. I have actually used it very little, but the concept of the prying tip seems sound for a tool designed for prying. The only thing sacraficed is penetration. The blade is partially serrated - all in all, a nice package. I can't speak to what steel you should use, but I would think something in my boot would want to be stainless - and a soft temper on the spine and perhaps the tip would help. This is a very interesting challenge you are undertaking. Keep us posted as to how it goes.
 
I forgot! Congrats on your new career. On that note, the sheath comes to mind. Not only does it need to be secure enough to protect you from your own blade, but you need to consider the issue of weapons retention. There are some very talented tactical sheath makers here - Eric Noeldechen of On-Scene Tactical comes to mind. You may want to solicit some advice from them as well.
 
I agree with Mr. Ealy about the S-7. CPM 3V is suppossed to be really tough, as well. You can see a comparison of several steels on Crucible's website. I think 1/4" should be fine. For heat treating, Paul Bos is the man for air hardening steels, you can heat treat your own carbon steel blade for a minimal investment of time and money.

Todd
 
i am just starting to use 3v and love the stuff been beating the hell out of 2 different "test" knives i will have to see what can be done to a car door and post some pix
 
Hi All,

Thanks for all the great ideas. I'm going to check out the Crucible website right now, but it sounds like S7 or 3V will be the steel. I had thought about coating the blade as well. Any suggestions here on an operation that has a reasonably short turnaround? Any good heat-treaters that apply coatings?

Again, thanks - I'll keep you posted.

SCDUB
 
Hi again,

So what about 5160 or other spring steels? Seems I have heard of them in regards to prying knives.

What do you think?

Thanks,

SCDUB
 
5160 is a great prying steel.Not quite as tough as S7 and 3V,but cheap and easy to work and HT.You might want to make a couple of them in 5160,go to a junk yard, and do destructive testing to see how they hold up to your applications.The handles can be duct tape for test knives.
 
the OB knife i used 3v and it took an edge well for a prybar not sure how hard its going to be to resharpen havent tried yet
i did the heat treat myself and tempered it to 57/58 Rc had a tool and die shop test it for me
 
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