tips_e1

Some production steps and hints

Production

Introduction
The whole theme "knives" is too wide to cover all topics, especially since I'm a maker, not a writer. Therefore I will limit myself to only a few interesting aspects about my method of making, about powder metallurgical steels, Damascus steel and about knife care.

1. Production

All my knives are handmade one of a kind. This does not exclude the possibility that:

more than one knife is made using the same design, usually with different materials,

some machines are used during production.

I even use a number of machines. I use a surface grinder on raw material and a mill for dovetailing integral blanks for inserting scales. The blanks are cut with a band saw and ground on a belt grinder. Also drilling machines, disk grinder and high speed grinder are in use. But all these machines have manual steering, none automatic. Therefore, each knife is made individually and has it's own unique characteristics.

The making of stainless knives with flat tang goes like this. The blank is cut from annealed flat steel bar with the band saw, it's flat ground and the holes for bolsters and handle rivets or pins are drilled. A hollow grind is made freehand on the contact wheel of the belt grinder, a flat grind on the platen of the same machine. This alone gives me the opportunity to make totally different knife blanks. This means of course, one must have a good training and concentration, especially for symmetrical blade grinds for daggers or fighters. The ground and drilled blanks are heat treated at a specialized facility in inert gas or vacuum and drawn to between 57and 62 HRc. After that the blanks will be ground with very fine grit and /or polished. Then the bolsters are riveted on and the scales are fitted, glued and riveted too. For the coarse grinding of the handle the belt grinder is used, followed by disk grinder, files and abrasive cloth up to mesh 8000, and finally polishing. Than the logo is etched, the sheath is fitted and sewn and the knife is sharpened. Other knife types like narrow tang or integral are made in a similar manner.

2. Material:

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The most important thing for knife use is the blade material. But since there are so many different types of use, no one can say :"this is the best one for all knives". There are three main criteria you have to take into account (and they all contradict each other):

1st: how long does the knife stay sharp in use

2nd: how much force is needed to break the blade (toughness)

3rd: how long does it take to achive a keen edge.

One can think of these three criteria as a sum: if you emphasize one , you drag the other qualities down. It is the knife maker’s job to select the right steel, the right heat treating and the right geometrical dimensions to optimize these three characteristics for the use the knife is intended for. To achieve this, in most cases longer discussions with the user are necessary. One must have a feeling for the purpose, the handling and personal preferences.

to 1st:
Powder metallurgical steels have the highest ability to hold an edge. The normal molten steel is limited very strong at the percentage of vanadium, molybdenum and cobalt, otherwise they would set irregularly at cooling down. During the powder metallurgy process, the alloying melt is sprayed to finest powders (grain sizes under 1 µ) and sintered (most under oxygen exclusion) at clean room plants in the HIP procedure (Hot Isostatic Pressing) with temperatures up to 1200 degree centigrade and pressures of 2000 atmospheres. This makes for high concentrations of components and a completely even distribution possible. It is a further advantage of this steel that the carbides of these metals (decisive for wear resistance ) only grow here up to 1 µ unlike the normal size of approx. 2.5 to 3 µ for conventional alloys;. This means that the blade can be sharpened to a finer edge. Examples of the stainless kinds are the American CPM T 440V and the Swedish ELMAX and the rust resistant (but not stainless) CPM 10V, Vanadis 10 and Vanadis 4 steels.

These steels reach (up to 25 times) better wear resistance at same hardness compared to good normal steels. However, the price for the improved performance of such highly alloyed steels must be paid in many cases (with the exception of Vanadis 4) with some losses of the ultimate strength and more difficult sharpening, as well as a 3 to 5 times higher cost of the steel.

to 2nd: The steels ATS 34 and 440B show a good toughness. With a little less wear resistance the same also holds for the 440 A. These are therefore particularly suitable for light knives with thin blades as well as heavy hewing knives. The powder metallurgical steel Uddeholm Vanadis 4 also achieves very good results in conjunction with very good wear resistance.

to 3rd: In general all stainless blades are more difficult to sharpen than plain carbon steel. This is mainly due to the high chrome content (14 to18%) which clogs the surfaces of the sharpening equipment fast. However, with suitable methods, razor-blade sharpness can also be reached with acceptable effort .

The emphasis on each of these characteristics can be manipulated depending on the desired use purpose (within certain limits) by corresponding heat treatment.

It's nearly impossible to force Damascus (pattern welded) steel into this system. Damascus steels are made of two or more kinds of steel and iron (or another material such as nickel), put together as multiple layers, forge welded, folded and again forge welded. This is repeated till the desired number of layers are achieved. The choice of material, number of layers, design of the blade and heat treating makes it possible to change the criteria of that combination within a wide range. There are two common characteristics: these steels will rust, for high chromium alloyed steels can not be forge welded in the traditional way, and they are easy to sharpen.

Saying they will rust does not mean they will rust quicker than you can take care of, like some people are afraid of. As an example, I take my knives to medieval markets. They lay on a table in a tent for 2 to 3 days, many people touch them (on the blade!). Afterwards they are put into the sheath (without wiping or oiling) and stay there until they are again inspected. That's not the way to treat a knife ! If during a year one of the knives shows a little bit of rust, it' a lot. Coating the blade with a fine coat of wax is the easiest way to avoid any problems with stains and rust under all normal conditions.

An other common criteria of the Damascus steels is the very interesting structure of the surface, that will never be exactly repeated. Etching with hot sulfuric acid (or some other acids) and polishing will enhance the beauty. The Damascus structures are so numerous I can't go in too much detail here.

Therefore I will explain only the most common: (look at Samples (302KB) :

Layered Damascus: These are all kinds where the layers are parallel in the blade; e.g. wild, ribbon- or wave Damascus; stamped Damascus such as "big roses" or similar. The number of layers generally range from 65 (often with a thicker steel layer in the middle) for working knives to 2000 for collectibles. Numbers up to 2 million and even more, like old Japanese blades, are also possible.

Mosaic- or picture Damascus: real pictures are put together like a mosaic using different steels. The blanks are cut cross to the "layers". These high complicated structures are nearly impossible to make without high pressure machines.

. Twisted Damascus: the basis is a layered Damascus with 7 to 32 layers. It's forged to a rod shape and twisted. These rods are stacked, in most cases twisted right and left alternating, and forge welded. Mainly the blades are made from 1 to 4 rods. More than 6 rods are called "Turkish Damascus". These blades often have an additional cutting rod of pure steel or high layered Damascus added to achieve a better edge. With the characteristic low number of layers this is done to avoid having long pieces of soft material which would be in the edge.

Wire or Cable Damascus: a suitable cable (big diameter, high steel contents) is forge welded

Chain saw Damascus: the chain from a motor saw or motorcycle is forge welded to a very interesting pattern.

The big problem with the both wire and chain damascus is to weld without bigger flaws and not to destroy the pattern.

3. Care
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It's a general rule to store a knife outside the sheath if it isn't used for a longer time. Damascus and all not stainless knives could start to rust. All knives with brass, bronze or nickel silver bolsters can react with aggressive substances in the leather (in the leather through some tanning processes). Stainless blades need only little care. All others should be treated with a good weapon oil. Needless to say, one should clean and dry a knife after use and never let it dry in a wet sheath at any heat source. Handles generally need no special care although slightly oiling or waxing doesn't hurt and can show up the structure of the wood even better. Sheaths are treated best with a good leather wax. This does not promote any oxidation of the knives as leather oil could do and doesn't soften the sheath.

Next, sharpening the knife and keeping it sharp one of the most important aspects of knife care. Hardness above 55 HRc makes it impossible to treat these knives like a butcher knife by using a sharpening steel rod to touch them up. A highly polished hard piece of steel can however be used to make the edge "bite" again for a while. Real sharpening demands for other methods.

Good old sandstone: called "Arkansas stone" in America or "Belgischer Brocken" in Europe, it is the oldest and one of the best tools to get a very keen edge - if one can use it right. It demands a lot of training to hold the same angle each stroke and on both sides.

Lansky or DMT Sharpening Set (or similar): because of the guidance of the grinding stones a very safe method allowing different sharpening angles; only it takes a lot of time: the stones are a little bit small. But beginning with the coarsest diamond stones available you will be able to set up an unsharpened blade. The finer grains are used to touch up a ‘set up’ edge.

Diamond sharpeners: there are so many of this kind, I only can say they will be able to sharpen the hardest blade, but you have to be cautious because of the high aggressive material removal by the diamond grit. Depending on construction the facts in the points said before are true.

Ceramic rods: mainly one or two pairs of rods made of special ceramic, stuck in a base to show a "V" at various angles. The knife is handled as if you want to shave the rods alternating with the blade vertically edge down. The "V" guarantees the sharpening angle. This type has been proven to be very good especially for untrained people.

Motorized sharpeners: most of them have a very steep angle and could get the edge too hot. These types are mainly usable for regrinding, but for sharpening you should use an other method.
There are paper wheel sharpening sets (one coarse wheel, one fine polish wheel) for installation on a spindle which work well without heating the edge. These are available in USA.

Closing remark

I hope to have contributed a little to the general confusion with these explanations. I would be glad to be available to answer questions . (e-mail, Fax or phone)

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