Monday, March 07, 2005

The Gift of a Knife

Some people say that the gift of a knife severs a friendship. Others, myself included, see the gift of a knife as a symbol of trust, of guardianship, and of strength (it's a visceral paganish thing really).

Of course that's only if it's a good knife, and most knives aren't. Perhaps there SHOULD be some credence to that whole severing a friendship thing, because I know I'd be pretty irked with a friend who gave me a $20 chinese knife, or worse, bought me one of those $100 "collector" knives off of QVC.

I'm a serious collector of working blades. I appreciate beauty in a knife, but first and foremost a knife is a tool; in fact mans most basic tool, and still among his most useful. I know I never go anywhere but inside an airplane or courthouse, without a good knife. I have maybe 30 very good quality knives, and a few premium knives, that I use and carry for different purposes; every one of my knives is, and always will be used. All of my good friends will also recieve a very good working knife from me at some point.

Given this, I have learned over the years how to pick out a good knife, for myself, or for my friends.

There are ten points to knife selection, and I'm going to cover them here.
  1. Purpose
  2. Person
  3. Steel
  4. Blade length
  5. Blade design
  6. Grind
  7. Finish
  8. Hilt construction
  9. Hilt design
  10. Hilt Materials

About 4000 more words in the extended entry...

The first point of knife selection, and the most important, is: what are you going to use the knife for? Different steels, blade designs, and grinds are used for different tasks. If you're going to be cutting boxes and rope, and carrying it in your pants all day, you want a different knife than if you're going to be skinning a deer.

I'm not going to go into choosing a style of knife, because there are far too many variables. There's a different type of knife for every job, and every hobby.

The only thing I will say is, make sure you choose the right knife for the job. Having the right knife makes the task much easier, and much more fun, while the wrong knife can make it a hell of a lot more difficult, if not impossible.

The second point is, the person who's carrying it: What size are they, what do they wear, how hard are they on their gear, and what is comfortable for them. Also important, how will they carry the knife (sheath, clip, on a lanyard), how often will they carry the knife etc...

Again, there are way too many variables for me to go into here, every man is different, and there's a different knife for everyone. Oh and yes, again, it's crucial you choose the right knife for the man. If it doesn't fit their life, and their body, it won't be used.

With these two factors analyzed, you can them make a decision about all the other options you have in picking a knife.

Moving into the actual physical factors of the knife, you have to choose your steel. This choice is determined entirely by what you want to do with the knife, and of course how much you want to spend.

There are two factors in choosing your steel, the alloy, and the heat treating. Good heat treating won't make bad steel decent, but it can at least make it servicible. Conversely bad heat treating (or the wrong teatment for the purpose) will ruin even the best steel.

The better the grade of steel, the more difficult it will be to machine, and the more expensive the blank will be, so the more expensive the knife will be. The higher end high speed tool steels are EXTREMELY hard, and take an edge very well. The more chromium in the steel the more corrosion resistant it is, and the more vanadium, molybdenum, and cobalt in the steel the better it will hold an edge (and the more expensive it will be).

There are two problems with the high speed tool steels: One; they are extremely hard, so they are extremely difficult, and expensive, to work with; after all they are designed to use in machining other steels. Two; the high speed tool steels are often somewhat more brittle than the normal tool, file, spring, or bearing steels at the same level of heat treatment. Those "lower" grade steels don’t harden in the same way, or hold an edge as well, but they are VERY tough and resilient, flexing where other blades might snap or shatter; not insignificantly, they are both cheaper, and easier to work with than the high speed tool steels.

For a general purpose hunting or fighting knife, I like a good high carbon steel, hardened from 56-60. Look for tool steels like D2, M2, O1, A2, W2, or some of file steels like W1 or 1095, spring steel like 5160, or ball bearing steel like 52100b, or 50100b.

NOTE 1: Metal files are often hardened to well above rc60, but when used in knives, file steels aren't hardened as much. Often a worn out file will be used as a knife blank, but it must be de-tempered first or it will shatter.

NOTE 2: Cold Steels Carbon V is believed to be 50100-b modified bearing steel. It is some very good steel, tough, and well hardened, but very susceptible to corrosion. Also most folks think Lynn Thompson (the propietor of Cold Steel) is both an arrogant asshole, and insane. Those people are right; but he's also pretty damned good at what he does.

For a pocket knife, a knife that’s going to see a lot of use in a wet or humid environment, or a knife that will be stored away in a trunk or a tool kit; I recommend a good high quality stainless or stain resistant knife or tool steel. Cheap stainless won't hold an edge for anything, but modern high performance stain resistant steels can have close to high carbon edge holding (though not its toughness). Look for AUS8, 154cm, ats34, S40V, CPM440V, CPMS30V, CPMS60V, VG-10, and Stellite or Talonite (which isn’t steel at all it's a cobalt alloy, but its damned good stuff).

As I mentioned above however, more important than the alloy used is the heat treating. A properly heat treated blade (for most alloys) should have a very hard, but not brittle edge, to hold a finer cutting edge; and a softer, more resilient back edge, choil, and tang to resist breakage. This is called differential heat treatment, and is used in better quality knives.

Generally speaking, on the grind, you want Rockwell hardness from rc55-60, with extremes of from rc50-64 depending on the alloy used. Below rc55 and most steel alloys won’t hold an edge properly; above rc60, and most steels become too brittle for hard use.

The reason a harder edge holds longer, is two fold. Dullness is primarily the rolling of the fine edge of a knife over to one side or the other, which presents greater thickness and duller angles to the material being cut; harder edges resist this better. The second element of dullenss is dents in the edge caused by harder materials digging into the blade itself. With a harder edge, you have less tendency to roll over, or to dent, but you trade off a greater tendency for the edge to chip or crack.

Ok so now that we've decided on our steel, our next question is length. Again this comes back to what the knife will be used for, who’s' carrying it, where, and when.

For a general purpose belt knife you want a blade of no less than 4", and no more than about 7". This allows you to have good heavy cutting performance, while still keeping control; in most situations.

For a fighting knife, or a wilderness knife, you may want something up to 9-10" to give you extra reach and chopping power (though there can be a tradeoff in controllability) . For skinning knives you may want as low as 3". Heck, in heavy growth, you may even want something like a Kukri , which is more than halfway to a machete, and can measure up to 18".

Folders are another story entirely. My personal thought is to carry as much blade as you are comfortable with on an every day basis. Personally I generally carry folders from 3.5" to 5" depending on what clothes I'm wearing, and what I'm doing that day. I have three every day carry folders, a Kershaw Ken Onion Blackout, a Benchmade auto mini-reflex, and a Mel Pardue Ambush, all three of which are one handed, fast opening designs with very positive locking mechanisms, and blades from 3"-4".

Once you have your length figured out, we need to talk about blade design. There are literally hundreds of different types of blade shapes and styles, but you can break the blade design into pieces to make classifying and choosing a style easier.

The basic components of a blade are the point, the spine, the foot or choil, and the edge.

The clip point is the classic bowie knife style point. They curve sharply down from the back edge in a concave hollow curve, and may have a sharpened false edge. Clip points allow a very sharp point with a lot of penetrating power on an otherwise broad bladed knife, but as a tradeoff, the point tends to be relatively weak.

Drop points take the spine of the blade, and curve it down very gradually in a shallow convex curve, to a point above the midpoint of the blade. This allows for a much stronger point than the clip point, with some sacrifice in penetrating power and controllability.

Spear points take the spine of the blade into a sharper convex curve to the mid point of the blade, like a single edged spear. This is an extremely strong point, but not a very fine one, and unless the false edge is also sharpened, or the blade spine is very thin, penetrating power is poorer.

A dagger point is similar to a spear point, only it is thinner, with a shallower and longer bevel to the point, and both edges are sharpened, preferably symmetrically. This results in an extremely weak point, but one that is very sharp, with excellent penetrating power. A dagger is intended as a thrusting weapon, and the strength of the tip itself isnt a high priority; in fact the tip on some daggers is inherently sacrifical; designed to allow penetration into hard muscle and bone, and then breaking off to allow withdrawal.

A tanto point blade has a gently curved, or straight edged main blade, with a sharply (45 degrees or more) angled secondary edge, cutting directly up to a point that is ground directly into the spine of the blade.

A modified clip point, or modified drop point combine the two point styles, with a bias towards one or the other. This is the most common point style on modern combat knives, and is generally expresses as a straight, or very shallowly curved (either convex or concave for drop or clip point respectively) angled drop from the spine of the blade to the tip, just slightly above the midpoint of the blade.

There are also modified tanto points common in American tactical fighting knives that have a gently curved main blade section, a shallower angle on the secondary edge, and a point dropped from the spine as in a modified drop point. The point could almsot be described as a modified clip point or drop point mixed with a tanto.

This style has been popularized by Emmerson and Benchmade, and Microtech knives, and is often called the american tanto, or the tactical tanto (because the styles of knife it appears on are often referred to as "tactical"). In theory this point type is a compromise in strength and penetrating power between the clip and tanto point styles, but in honestly the reason for this point type is style.

Moving on, the spine of the blade is it's backbone, and is the primary element of it's strength. The spine on most knives is generally pretty plain, but the thickness of the spine has a huge impact on the overall design of the knife. A thicker knife will be much stronger, but will generally have less cutting and penetrating power, and will be more difficult to machine and grind. Oh and of course, a thicker knife will be much heavier as well.

The choil or foot of the blade, is the spot where the tang or hilt transitions into the cutting edge. Sometimes the cutting edge continues all the way into open air (skinners and chefs knives), or directly up to the hilt (slicing and carving knives). This increases the slicing power of the blade, and in a deeply curved knife with a lot of belly to the edge, can increase the control. Some blades have a deep choil, and may have a ricasso (an unsharpened area between the hilt and cutting edge) from 1/4" all the way up to 2".

Most fixed blade general purpose, hunting, and fighting knives have some kind of choil, and some ricasso, as a side effect of the blade and edge grind. A deeply ground blade with a thick spine will generally have a very deep choil, which retards the cutting ability, and increases difficulty in sharpening, but increases the strength and safety of the blade.

Which brings us to the next factor for consideration, the blade grind and edge grind.

On most knives, the blades grind starts somewhere below the spine. Exactly where the blade grind starts is generally referred to as the grind line, but is sometimes referred to as part of the choil, and the part of the choil at the foot of the blade (which I referred to above as just the choil) is called the bit. The blade grind, and edge grind are critical to the performance of the knife, and are directly determined by what you want to use the knife for.

There are three basic types of grind: hollow ground, lenticular (convex) ground, and flat ground. There are also three modified grinds, the chisel ground, saber ground, or dagger ground blades.

A hollow ground blade has a concave surface from the spine, or the grind line, to the edge. This reduces the thickness of the blade greatly towards the edge, and allows for a much thinner, and therefore sharper edge on a thick spined blade. Hollow ground blades are the most common for classic pocket knives, and for traditional straight razors.

Hollow ground blades are the best for making shallow cuts, for slicing thin materials, and for shaving. A deeply hollow ground blade will have a weak edge as compared to its spine, and as compared to all other grind types; Also the curved wedge shape can retard cutting power in thick and tough materials because the angle of the grind changes sharply as the material being cut approaches the spine of the blade, which can stall the cut.

Lenticular blades are the opposite of hollow ground. They have a blade grind like a lens (thus the name), gently curving from the spine, down to a sharp curve at the edge. This allows for a very strong edge, and a very strong blade in general, but it won’t allow for as fine an edge as hollow or flat ground, and as the angle is very sharp and the blades aren’t thinned as much, it can be difficult to push through materials. Lenticular blades however are very good at slashing and chopping without hanging up in material being cut, or damaging the edge.

A flat ground blade is just like it sounds. From the spine (or the choil) the blade is ground flat to the edge. This is a compromise between the strength of the lenticular, and the fineness of the hollow ground edge. Flat ground knives are sharp, but can’t be as sharp as hollow ground blades without being ground too thing. They are very strong, but can’t be as strong as the lenticular blade without losing slicing power.

The flat ground knife has the greatest slicing power in thicker or tougher materials, because the angle of the blade is a constant, so the knife won’t hang up; Notice almost all chefs knives are flat ground for this reason. Flat ground knives also have excellent slashing power, but they are more likely to hang up in the material during a slash or chop.

The combination grinds are just what they sound like. A chisel ground blade is generally a flat ground blade, which is only ground on one side. A dagger ground blade is hollow ground on both sides to make a star or diamond shape. A saber ground blade transitions from flat to hollow ground, or is a multiple angle flat grind, and it may have a ground back edge, with a false edge.

After blade grind we need to talk about edge grinds; there are two main edge types, plain(or fine) and serrated, with many subtypes of each.

Plain edges are better for push cuts, fine cuts, and thin slicing; also, in general, fine edges give you more control over your cut. Serrated edges are better for pulling, sawing, and tearing cuts, especially in fibrous materials. Serrated edges generally produce a rougher cut, and give you less control, but the edge will generally last longer, because there is actually up to three times as much cutting edge being applied to the material being cut.

There are also four edge shapes to consider: The curved, recurved, hooked, and straight edges.

Most knives have a shallow curve starting at the point, and sweeping into a straight edge section about a third of the way back from the tip. This curved section is called the belly, and is used for slashing, curved push cutting, turning in a material being cut, and skinning.

The straight section of the edge is used for straight push cutting, and some pull cutting. It is also used for very fine slicing, as you have more control of a straight edge, close to the hilt. Straight edges are best for controlled push cuts, and for chopping, because they split the material away from the blade better.

The more curve you have, the more curved slicing power (slicing maneuverability and dirctionality) you will have. This is critical in skinning an animal, where you have to follow the contours of the animal. Curved edges are also best for slashing, because the curve of the blade is at an angle to the motion of your hand, which pushes the cutting edge deeper into the material, giving the edge more bite. This is reinforced with recurved edge, allowing the belly of the blade to bite very deeply, and continuously exposing a new section of the edge to the material.

The final blade related factor is the finish.

The finish of a blade isn’t entirely cosmetic. Corrosion resistance is critical in a working blade, and the finish of the blade is an important part of that corrosion resistance. There are also some finishes that reduce friction in a cut, or make it easier to clean a blade up after you're done working with it.

The common finishes are listed here:

1. Polished metal
2. Brushed metal
3. Bead blasted, tumbled, or media blasted metal
4. Black chrome, black Teflon or other chemically bonded blackening
5. Nitride
6. Powder coat
7. Epoxy finishes
8. Parkerizing
9. Blueing
10. Plating (nickel, gold, chrome, others)

My personal preference is for brushed metal finishes on all my knives. This allows me to buff out scratches, and not worry about a shiny polish, while being non-reflective, and if I'm worried about corrosion I'll generally go for a good quality stainless rather than depending on the finish.

That being said, there are certainly some good finishes to choose from.

The epoxy and powder coats vary in toughness from Glock, Ontario and Cold Steels "tougher than the knife itself" finishes, to buck's horrible blackened finishes that scratch with a light breath.

A good black chrome finish is nearly indestructible, as is a black-t Teflon, or a good nitride finish. All of the finishes I mention here are actually somewhat self healing (light scratches will tend to disappear over time).

Unfortunately most blackened finishes don’t stand up to tough use. Benchmade has used some great blacking, and some horrible blacking in the past. The same goes for Buck, and Ka-Bar.

Bead blasted finishes may look cool, but they scratch easily, and they stain, and rust easier unless they are oiled properly, because the micro-roughened surface retains moisture and salts.

Oh and with regards to finish, there are two important things to remember: stainless steels aren't, and even with a corrosion inhibiting finish, a carbon steel blade should always be kept lightly oiled.

Next up, hilts.

The most important factor in hilt design is the hilt construction. There are too many folder variations to get into here, so I’m not going to, except to say make sure you choose a positive locking mechanism with strong pins, buschings, and bolsters.

In fixed blades there are really three knife construction types worth buying, and well talk about those here:

The three basic hilt types are one piece, full tang, and full length tang.

One piece is just like it sounds, the entire knife, hilt and all, are one piece of steel. When properly done this results in an extremely strong, tough knife. There’s really nothing to break. That said, they are surprisingly difficult to make both strong, and comfortable at the same time. One piece hilts may be covered with rubber, leather, wire, or cord to increase the grip, and comfort.

In a full tang knife, the blade blank extends the full length and width of the hilt. It will have scales of some material attached to the sides of the tang, or will be wrapped in cord or leather to improve grip and comfort. It is easier and cheaper to make a high quality, strong, and comfortable full tang knife, than a one piece or full length tang knife, because the blade blank stays the same thickness the whole way through, simplifying machining. If something does break, it's going to be the scales or wraps, and those are easy to replace. Even with a broken handle, the full tang knife is still usable.

In a full length tang blade, the blade blank is greatly narrowed behind the hilt or foot of the blade into a rattail, or a shaft. This is where the style gets its other name, the rattail hilt. This is somewhat misleading, because a rattail is actually not a full length hilt design, but as many knives were made from rattail files, the name stuck. Just be sure that if the knife has a rattail tang, that it is full length.

Most full length tang knives will have a seperate quillion (cross piece or finger guard), a handle, and a pommel of some kind. This pommel will generally be pinned or screwed into the tang, with the handle material slipped, molded, or wrapped over the tang, with the pommel as a retaining nut. Some designs do not use a pommel; they widen out, hook, or flatten the tail of the tang, and then mold the handle over it, or thread the end of the tang, and screw the handle on directly without using the pommel as a nut.

The full length tang gives you anything from about the same strength, to a lot less strength than the others, but usually still sufficient for almost all purposes. The advantage of this tang type is that it allows for the best ergonomics, with handles that can be made to fit the hand more comfortably than most full tang or one piece designs. This is by far the most popular hilt design for general purpose fixed blade knives of the past 50 years, but the full tang design has been making a comeback over the last few years with "tactical" knife designs.

In terms of hilt materials and shape, those are really up to comfort, aesthetics, and durability.

If you want a very tough hilt, use leather, or micarta. If you want non slip, use kraton. If you want beauty, use micarta or wood etc... etc... etc...

The options are endless.

As to makers, I own or have owned, and very much like the following:


Cold Steel

Custom and Semi-custom

Al Mar
Allen Elishewitz
Pardue (either one)
Ken Onion

Finally, given all these options, what should you buy?

Well for a general use belt knife, here’s what I recommend.

A 4-6" modified drop point blade, plain edged with a good belly, in a high speed tool steel with a brushed finish, a full tang, and sculptured micarta scales.

Alternately, the same knife with a full length tang and a comfortable wood, micarta, or rubber hilt, depending on whether you want more beauty, or more comfort.

Now, that was easy wasn't it?