Forbidden Donut

Since a lot of you seem to be in various branches of military now, I thought I'd crack an egg of knowledge all over you wrt knives.

I happen to know quite a bit about steel and knife manufacturing (as soon as I'm out of an apartment I plan to make them), so I thought this might be useful.

Before we begin, here's some information:

edge holding/retention: This term refers to how long a knife stays sharp enough to cut.

HRC: This is the "rockwell hardness" of the steel, which is just like it sounds; it's the measure of how hard the steel is. This is important because the trade off of any type of steel is harder=sharp longer and softer=more durable. Keep in mind this must be considered only in regard to one steel type, meaning, for instance, different steels at 56HRC do not have the same edge holding and durability. What HRC the steel should be is dependent on the type of steel as well as application of the knife.

carbon steel vs. stainless steel: Generalizing, carbon steel is more durable and at least equal to stainless in terms of edge holding. Steel must have at least 13% chromium to be classified as stainless. Stainless is common in folders today because people don't know how to take care of knives. In reality, carbon steel is better in every way at every price point. That said, there are so-called "super steels" like the ZDP's made by Hitachi of Japan that are a step above all others when it comes to staying sharp (although it is run to such a high HRC that sharpening is a huge pain in the ass by hand). In regard to the rust resistance of carbon steel, the ones I mention below aren't bad. As long as you wipe them down after they're wet, they won't be a problem. In a very humid environment, something like mineral oil (if you use it for food prep), tuf-glide (a waxy oil made for knives), or any other oil will keep rust away. Another option is 'forcing a patina', which involves making the steel oxidize in a way that slows andor prevents real rusting.

heat treat:Heat treating steel is what makes it hard so that it holds an edge. There's not one way to do it, and it's the heat treatment that makes or breaks any knife.


Recommendations (see below for info on steels, grinds, and brands):

The standard brand military knife is, of course, Ka-Bar. Ka-Bar knives are made of 1095 Cro-Van at 56-58 HRC. At that HRC, you're going to have trouble breaking one, but it also doesn't have the greatest edge holding.

A worthy successor is ESEE Cutlery. With 1095 blades at 58-60HRC, they have much better edge holding, and they still have very good durability. To put it in perspective, their smallest knife, the Izula, is 1/8" thick at the spine, and they have only had one break (a guy tried prying open a locked window and broke the tip off). Most of their knives are 3/16" thick, which is plenty durable. They make one knife that is 1/4", the ESEE-5, and it was designed for military pilots who go down and have to cut through the metal hull to get out. In other words, shit ain't gun' break. Their knives are very reasonably priced, and they will replace any knife broken for any reason (more in the appendix). Finally, they have regular versions and 'clip point' versions, which means the top edge towards the tip is sharpened to make stabs penetrate easier. For regular use, the ESEE-3 is a very fine knife and comes in a military version with a sharpened butt end (ESEE-3 MIL).

Pic of the ESEE 4 in tan:


ESEE-5 (notice it also has a sharpened butt end):


Another option for the price-conscious is Scrap Yard. Right now they have a bowie knife called the Regulator aimed at the military for $99 (if you're in the military, $109 if you're not). At 1/3" thick and with a saber grind, you'll have trouble even breaking the tip. This knife will last your enlistment and then be passed on to your son when he enlists. At the price, there is no better knife. At twice the price, there still isn't. With no overstatement, I would recommend this knife it was $500. It is made of SR101, which is their name for 52100. Scrap Yard (and Busse and Swamp Rat) make a knife for only a short period of time and may never make it again so jump on this.

Pic of the Regulator:


For people with money to spend--or demand the best--there is one option: Busse. Busse uses a proprietary steel, INFI, not available anywhere else that has great rust resistance, amazing durability, and amazing edge holding. It is the pinnacle of knifes. For a 3-5" blade, expect to pay $250-$350. For a larger size, expect to pay up to $600. At a live show, the owner, Jerry Busse, repeatedly cut pieces from a 1000' spool of rope, only stopping when it ran out, and then shaved hair off his arm, which is unheard of, as rope dulls every steel fast. Interestingly, INFI is one of only a couple steels that dulls and then resharpens itself just from cutting. A reason hasn't been given for this, but I suspect that the molecular structure is such that certain elements stay attached as others come off with use, which produces a thinner edge with use (INFI includes nitrogen, which, with it's trivalent bonds, forms much stronger molecules than the covalent bonds of other elements) As for durability, see for yourself: http://www.knifetests.com/BussefFFBMtestpage.html and compare it to the KaBar bowie http://www.knifetests.com/page2.html and KaBar USMC knife http://www.knifetests.com/page6.html, which failed the tests early on (whereas the Busse is the only knife ever tested to pass everything). (The Scrap Yard Scrapper 6 also faired better: http://www.knifetests.com/scrapyardscrapper6test.html. As well, the ESEE-4 (they used to be called RAT, so it's called the RAT-4 there) was rated the same as the KaBar bowie despite being thinner (and, remember, is a higher HRC so holds an edge better) http://www.knifetests.com/ratrc4dtest.html .)

Here is the popular FFBM (sold for $520), the Sar-5 (sold for $220), and a non-Busse (Swamp Rat) Hairy Cairy (didn't sell but listed at $165)



Appendix:

Brands:

Busse: Busse has a cult following, and many people buy the knives only to collect them, despite the fact that their steel, a proprietary type called INFI unavailable from anywhere else, is considered by many to be the pinnacle of knife steels. What do I mean by cult following? Last week they listed and sold 1000 knives in 10 minutes. (There is an active second-hand market, however, and with so many collectors, you can find pristine and user versions regularly.) Do not be fooled into thinking because they're collected that they aren't good users. You'll pay a premium for a Busse knife in the same way you'll pay a premium to build a race car. They're expensive because they're the best. Busse, Swamp Rat (below), and Scrap Yard (also below) warranty any unintentional major damage; if you break it, they'll replace the knife.

Swamp Rat: Swamp Rat is a Busse brand that uses steels they call SR-77 and SR-101, which are just S7 and 52100 using their secret heat treatment process. They're very good knives at less than half the price of a Busse.

Scrap Yard:Scrap Yard is run by the brother of the owner of Busse. The idea is he goes through Busse and Swamp Rat's scrap yards for left over steel to make very cheap (for what they are) knives that are still very good. Given that they use SR77 and SR101 (and only once INFI), they're the best knives for the price.

ESEE: ESEE has the best warranty of any knife company. If you own a knife and it breaks, you can send it to them for another. You don't have to be the first owner, and you can break it in any way you want. The owners, Jeff Randall and Mike Perry, spend a lot of time training military and police in South America and have recently started doing it in North America, as well. They are the real deal. If you want to talk to them, they answer email and posts daily in their subforum on bladeforums.com, which is not something you can say about many companies. They make knives to be used not collected. Their knives are made by Rowen Manufacturing, which is run by Shon Rowen, who also responds to posts on bladeforums. Rowen manufactures 1095 to perfection. ESEE knives are priced around the cost of Scrap Yard knives, and although they use 1095, which is a step below, with the owners and warranty, they are a worthy consideration.
edit: Read this thread I just saw, and you'll probably end up buying a knife from them: http://www.bladeforums.com/forums/showthread.php?t=741009

Types of steel (all of these are carbon steel, not stainless)

1095: 1095 is a standard of the industry. It has good durability and good edge holding. At 56-58HRC, there aren't many Ka-Bar knives that break. At 59-60 (which is what most custom makers as well as ESEE use), the edge holding is amazing, and you will still have trouble breaking them.

1095 Cro-Van: This is 1095 with chromium and vanadium added. Chromium adds rust resistance (and to a lesser extent hardness and edge holding), and vanadium primarily adds wear resistance. In my experience, larger amounts of vanadium also give the steel a toothiness that makes the steel really grip and rip away the material (though I don't notice much difference in Ka-Bar knives, possibly because of their lower HRC).

52100: It was first a ball bearing steel, but it's been ported to knives because of great durability (better than 1095) and even greater edge holding. It's found in both big choppers and small fixed blades. It happens to be my favorite knife steel.

5160: 5160 is a bit more durable than 52100 but with a bit worse edge holding. As a result, it's found in big choppers where durability is the chief concern. I'd rate 1095 as holding an edge better if both are heat treated to perfection.

3V:3V has amazing durability and edge holding in between 5160 and 52100 (it's no slouch).

S7:S7 is the steel used in jack hammer bits, so you can imagine it's very durable. It's edge holding is alright but not up to 52100.

INFI: 52100's edge holding with better durability and rust resistance. The only problem is it's made by only one company so demands a premium price.


Grinds:
Knife grind refers to the shape of the blade from edge to the top. First, here's a picture of some:


1=Hollow: Hollow is used because it has the least amount towards the bottom of the blade, so for shallow cuts (i.e., cuts where the material isn't traveling all the way up the blade), it's the best. For the fact that it has the least material behind the edge but also potentially a lot of material and thus weight above, it is used in some choppers. Because it is thick above the hollow (concave) part, it is also durable. Where the hollow part ends, though, is a 'hot spot' where material will catch if you're doing something like chopping wood.

2=Flat: Flat (a.k.a. full flat and FFG) is popular with outdoor enthusiasts because it's the best grind for chopping wood, as there are no 'hot spots' where material will catch.

3=Saber: This is a deceiving picture because some saber grinds form a peak in the middle where from there to the top it gets smaller (think of a sideways "V"), but both are technically saber grinds. Saber grinds transfer width to the tip, so they are durable fighters.

6=Convex: Convex knives have the most durable edges because it puts the most material right behind the edge. Although the picture is full convex, you can actually just convex near the edge of any grind (and leave the bulk alone). To do that, all it takes is use sandpaper lifting the blade at the spine (i.e. opposite side of the edge). I convex the edge of all fixed blades.


I'll respond to any questions.