NooB 5160 Questions

[chewbacca]

I have been thinking of making a chopper for a while. After looking at a lot of large knives (Becker Brute, Kershaw Outcast, Busse Battle Mistresses, Fehrman Final Judgement...the list goes on) I have settled on a design. 15-1/2" overall length with about a 10" blade. Settled on 5160 steel. I am going to have the blanks water jet cut.

Here's the question...If I decide to have the blades hardened on the outside, what Rockwell hardness should I be shooting for in a chopper in 5160 steel? I know Ranger knives use 5160, and are well respected over on the Wilderness and Survival forum, and they are hardened to 58RC. Is that the number I want?

I may try to harden and temper myself. If I do is 1475°F a good temp to use for hardening 5160? I see this number a lot when talking to about 1095. How long should I hold this temp? Can I use the same color indicators when tempering 5160 as I would use for 1095 (spine brown->plum->blue->straw near the edge? Or should I try to only harden the edge, and not the rest of the blade?

I know this is a lot of requested info, and I appreciate any help you can give. Thanks in advance.

 

[Russ Andrews]

5160 will harden all the way through...the chrome in it makes it a
deep hardening steel. It needs 1550f to harden properly...soak a few
minutes, and quench in a proper oil. Temper @ 350-400, two hours
twice.
Many a bladesmith has passed the JS performance test with a 5160
blade.

 

[chewbacca]

Thanks for the info. How long do I let it cool between temperings? Just back to room temp?

 

[Russ Andrews]

Cool just to room temp after first temper, then temper
the second time.

 

[JTknives]

soke for 5-8 min at 1550

 

[flatgrinder]

Temper @ 385.

Have fun.

 

[silver_pilate]

Good recommendations here. Chewbacca, keep in mind that each steel has a particular set of heat treating criteria. What works for 1085 may not work for 5160 or O-1 or L6. While steels with similar composition will often harden at near the same temperatures or soaks, it's a good idea to look up the specific steel you are using and find what's known to work. As for tempering, use your household oven or a toaster oven with a internal oven thermometer to check your actual temp. Don't worry about using colors as there are many variables that can change the color/temperature relationships. Most steels have charts that will associate a known temperature for tempering with a desired final hardness.

Make sure you post us up some pics when you're done!

--nathan

 

[chewbacca]

Thanks again for the info. So far, I made a hardboard mock up, and didn't like the handle, so it has been redrawn, but no second mock up yet. I want to be sure I like the feel before I have someone put the water to the steel.

 

[Garrett Schmidt]

Are you using a grinder? If so, then you could profile it yourself. You'd be amazed what you can do with a $100 craftsman belt grinder and a cheap harbor freight drill press using sanding mandrels....that's what I use still. I also went with 5160 to start with.....mainly because it is so cheap in bulk. Good luck.

 

[LRB]

How a knife is ground will determine how it will cut, steels do not cut, geometries do
Dude! That is total BS. Geometry is very important, but if that is all that counted, we would be using 1018 for our blades, and why bother to HT?

 

[Garrett Schmidt]

How a knife is ground will determine how it will cut, steels do not cut, geometries do
Dude! That is total BS. Geometry is very important, but if that is all that counted, we would be using 1018 for our blades, and why bother to HT?

Are you refering to Flatgrinder's sig line? I was confused as to what you were refering to at first.

 

[LRB]

Yeah, I was referring to Flatgrinder. I could not get the quote to work. I think that is a completely ridiculous statement for any knifemaker to say in a blanket mode. I don't want to offend, but that is just, I want to say stupid, but I won't. Geometry is important, but the steel plays a little bit of a role in the equation, don't you think? Not to mention the proper HT of it. There is no one thing that makes a good knife. It is a combination of the right stuff that gets it done.

 

[fitzo]

I feel the quote is a good example of the potential hazard involved in abstracting one line from the greater context in which it was written. Within the context of that original thread, it made decent enough sense.
To make a good knife, all aspects of the gestalt must of course be considered, from design to materials to heat treat to construction and the bevel and edge. What was being discussed, though, was for the cutting action itself, regardless of edge retention, strength, etc, geometry is the predominating factor. I don't fully agree, but there is a degree of truth to it.
It was only a few years ago that a well known bladesmith gave a demo at a hammer-in wherein he passed all the ABS cutting and bending tests with a blade made from 1018. Perhaps someone can provide the specifics....

 

[Stacy E. Apelt - Bladesmith]

I'm with Mike here.
It is important to use a good steel, but the final cutting ability is a function of the edge geometry. I have received a paper cut that nearly required stitches. The worst cut I ever got was from a piece of sheet metal. Neither was anything near knife steel in hardness. As I have said in prior posts, "A 1030 blade with proper geometry will out cut a 1095 blade with poor geometry." Edge retention, hardness, and the other parameters are all important factors in a knifes durability, but geometry makes a knife cut - the prime factor is physics, not metallurgy.
Stacy

 

[LRB]

Well, that makes more sense of it. My apologies to flatgrinder, but he might should be a bit more explicit in such statements

 

[chewbacca]

Here is a pdf of the design. I plan on using a 1-1/4" flat grind on the 1/4" steel, this will give me around a 5° angle. The top of the spine will have a false edge about 2" long. I am planning on home-made micarta handles.

 

[flatgrinder]

Well, that makes more sense of it. My apologies to flatgrinder, but he might should be a bit more explicit in such statements

No worries. :thumbup:

Just an old phrase that Cliff used a long time ago. Steel choice is important -but if you choose something that is time tested and proven, final geometry is what matters. Too much money and time is spent these days looking for a "fad" steel that either performs a bit better or not at all.

eg. 154 CM, Ats-34, CPM 154 in all it's incarnations, when properly heat treated and cryo'd to HRC 60-61 will hold it's own for a hunting knife. Similarly, 5160 is an excellent steel for a chopper.

P.S. Chewbacca: I would recommend a full convex grind on that chopper for maximum efficiency -Moran style grind, not too thick. 1/4" stock is fine.