22 Jul
Blog

Financial Advice

JOHN RUSKIN (1819 - 1900)
English philosopher, artist and esthetician.

Financial Advice

It is unwise to pay too much, but so is paying very little.
If you pay too much you lose a little money, that's all.
If you pay too little, sometimes you lose everything.
Because what you bought was unable to doing that for which you purchased it.
Popular Law Trade Balance is unable to pay very little and getting much. Simply ``can not be``.
If you close dealings with the lowest price, it is good to add a margin for the risk taken.
And if you can do that it is because they have sufficient to pay for something better.
JOHN RUSKIN (1819 - 1900)
English philosopher, artist and esthetician.

Something worse and cheaper

Some will always do the same something worse and cheaper.
Alfredo Kehiayan

An adequate tool in inadequate hands, produces inadequate results.

Alfredo Kehiayan

Creativity is not just around every corner and those who do not have it... copy.

22 Jul
Blog

Definitions of Crafts

Definitions of Crafts

Nineteenth edition (1970)

Dictionary of the Spanish Royal Academy

Craftsman (from the Latin: Artesanus, and this from the Latin: ars, artis, art).
Person who exercises an art or mechanical craft.
More recently we distinguish with this name he who makes his own household objects imprinting a personal touch, unlike the factory worker.

Ateneo Encyclopedic Dictionary

Crafts: Any form of production that uses manual procedures and rudimentary machines and devices.
It is characterized by a confection made with personality and a sense of popular art, and if it does not reach the category of artistic creation, requires for its execution skill, ability, good taste and has the impression of the craftsman style.
Each product is a unique example and is opposed to mass produced by industrial procedures.
Publisher: Ramón Sopena S. A. (1965)

Illustrated Encyclopedic Dictionary of Spanish Language

Crafts: Work or artisan work, especially if it has artistic quality. Everything is done by man's ability.
Artisan: A person who has an art or mechanical skill.

Is clear that “artisanal” is not a mere manual work, it is usually done by hand but with “added value”.

It is acceptable to do some part by machine if the artisan can do something for which this machine has no qualifications or conditions, ie that succeeds thanks to his skill and ingenuity.

Also that quality can be considered as “art”.

According to the dictionaries the etymology of “Artisan, craft” comes from Art. While not classified as Fine Art, it must have something… some artistic flair.

Ingenuity, creativity, design, style, personality and everything that the artisan has to whether to put into the work.
Otherwise it would simply be manual labor.

Alfredo Kehiayan

If the quality of the work is meritorious, the pride is deserved; if not it is mere vanity.

José Ingenieros (1877-1925)
Argentine writer, philosopher and psychologist.

22 Jul
Blog

Criteria to make a good knife

Criteria to make a good knife

Let’s see how the blade should be designed to cut well and can be sharpened easily. To qualify it as a “good knife” is important to have the following qualities: good steel, good heat treatment, structure and appropriate edge angle. All must be present.

Besides the good steel and good heat treatment it is important that the blade structure including: the type of rebate, thickness and angles. These details will determine that the knife will cut well, for a long time and let his sharpen easily.

Almost every beginner makes the knife blades with convex sections (Figure 1). It is a primitive criteria leaf design. It is very easy to make and very low cost, more similar to a machete (for a machete, you do not need a fine cut), it is only useful for chopping and axing branches or something.

Another very common type of construction is shown in (Figure 2), which are unsuccessful knives simply because they do not cut.
Right angles are for a chisel, not a knife to cut the things we want to cut with a knife.

Often you will find a blade is made from a flat-parallel small plates, a rebate at an angle of approx. 25º and a bevel cutting edge of 55-60º, even up to 70º in some cases. You should be reject the acquisition of a knife of these characteristics… it is useless. Another widespread type of blade is made in a flat-parallel small plates with a small concavity as shown in (Figure 3).

When it is new (see position A) it will cut relatively well until the wear and tear from use and the resharpening transform it to position B, where we find a piece similar to the case of Figure 2 with a cutting angle excessive for a knife blade.

So here we are eliminating many grams of useless steel.

Creole blades with section illustrated in (Figure 4) have good performance at the beginning (position A), we use a section something thicker at the cutting edge (position B) which is going to be difficult for resharpening because it increases the worn surface, and so requires “lowering” the blade.

I made blades of Creole style with a slightly concave to reduce this problem.

We have finally the (Figure 5), where we see a blade of unusual section. This blade enhances the cut because it offers no resistance to penetration (position A). Think of a wedge, if it is thick and the angle is large, the effort to achieve the penetration should be greater.

In the figure we see that the blade is a strip approximately 15 mm wide (parallel to the cutting edge) and 0.5 to 0.6 mm thick.
The thickness of the blade in the cutting edge area, should be 0.4 to 0.6 mm, maximum 0.7 to 0.8 mm depending the abuse that is intended to submit the knife and with respect to cutting angles aproximdadamente 20 º for general use. Minimum 15 and maximum 25 º.
If this is a knife to cut very thin cold meat the angle can be reduced to 10 degrees or less, but limits its ability to cut something hard.

In closing let me share my attributes of a “a good knife”:

It should be lightweight (unless it is one of those 4×4 knives which clearly we have for abuse, axing, hitting, breaking everything).

For this case the weight of the blade should be appropriate to the demands we’re going to submit. The weight should never be in its handle.

The weight of the handle should not be larger than necessary. It must be able to control everything that can be done with the blade. Any excess is useless, and can be harmful. Its hardness should be optimal (60 RC) for a Durable cutting edge, without being difficult to resharpen with simple elements (flatstone, steel sharpener, etc).

And preferably the blade steel should be corrosion resistant.

There are many concepts or criteria to evaluate or qualify a good knife and these are the ones that I think are the best, but nobody can affirm that really they are.

Finally, its qualities must justify the price paid, “if worthy, is not expensive”, is expensive “when the price exceeds its value”.

21 Jul
Blog

Suggestions about a knife

Suggestions about a knife

The knife is a tool and as such requires caution in its use and care in its service. If cared for it can be expected to give good performance and duraibility for many years. It is a pleasure to feel the cut with a knife in optimal conditions. It will perform for you and you will feel affection for it. Do not lend it to anyone although you may feel selfish for not having done so.. If the knife cuts well, it should not be lent to others.

Do not insert the knife dirty or wet in the sheath. The remains of food and other substances containing salts and acids that remain permanently in the sheath and will corrode the blade while it is stored. Wash it with whatever you want, even with hot water and detergent or soap, although you will have to clean it from tip to end with a paper towel or cloth moistened with any clear liquid (water, soda, wine, etc.). Bacteria and microbes are another topic…
This recommendation is also valid for the knives called “stainless steel”, because “a good stainless knife “is not really stainless, simply good or medium corrosion resistance and it needs to be cleaned completely before sheathing. If it is carbon steel, I suggest you lubricate with a reliable preservative when clean and dry before storing it in its sheath.

Cut only on wood or soft synthetic material (plastic). If you cut on marble plates, grill, etc. you will damage the cutting edge.

Do not pry with point of the knife, because it is not a barrette! or a paint can opener or a screwdriver.

To restore the edge (nothing is eternal), just a stone seat not too hard, medium grain, which may be an Arkansas (the best natural stone), ceramic or diamond powder should be used. You must support the blade with the edge angle (10° per side approx.) and draw the entire length of the blade across the stone surface, without much pressure and with a good lubricant (WD-40 is the best I know), doing all possible moves in circles, diagonals in both directions or “eights”, whichever you prefer.
A steel sharpener with fine knurled, ceramic or diamond powder also give good results, but requires some skill.

If you can’t successfully do it, come see me, I’ll explain personally.

And please… don not destroy the excellent Argentine meat with those serrated abominations that people calls a “steakknife”. Do not be swayed by infamous and scoundrel advertising.

A good knife is for all life, or more. A valuable knife is not “expensive” and can be a good investment.

Finally… each one has the knife they deserve.

Alfredo Kehiayan

21 Jul
Blog

Cutting Demonstration

Cutting Demonstration

A group of friends met to “reenact” and compete in cutting reeds, cans, etc. using knives, swords and katanas.
We cut several canes tied, empty cans and bundles of reeds (of 4 inches), starting with a bunch, following by two, three, four and five bundles of reeds (each of 4 inches in diameter).
I took my kitchen knife and was greatly encouraged. The objective was fun.

Knife on high as to behead the enemy.
And the knife goes!
Is going through…
Finished through and the enemy still stands
Continues…
And continues standing
Still alive…
Do not want to drop…
But it begins to bend…
And… Finally drop!
Totally expired!!!

The sequence of images was taken from the film.
Is clearly seen as the knife passes through the reeds, but they do not feel the impact and stay in their place. This indicates that the bundle of reeds did not feel the impact. After all day of cuts, the sharp edge is still very good although having a hardness less than optimal (the “known” 60 Rc).

Something similar happened with the can, despite being placed on balance over the rushes, did not feel the impact, took a moment until it fell.

The knife threatening…
Going fast towards the target
Is cutting…
Has been cut and the head falls
The body doesn’t move even
Still in place, did not notice that his head was cut
Moves a little…
Continue leaning slowly…
Loses stability…
And want to fall …. when the decapitated head is reaching the floor.

All this without sharpening the knife the entire day. The objective was to test the cutting power and durability of the cutting edge.

The Knife

This is my modest kitchen knife which cut the cans, the reeds and the reeds without sharpening. And humbly returned to his daily work in the kitchen.
The blade is made of AISI 420 steel, hardened to 57-58 RC. Size: 5/32″ x 2″ x 81/4″ (4 x 50 x 210 mm, and the ergonomic handle is of Guayacan.

20 Jul
Blog

Temper and hardness

Temper and hardness

Explanation of the qualities of thermal treatment

The thermal treatment, known as hardening or tempering, is a fundamental aspect in the behavior of every piece of steel. The steel must be hardened to enhance their qualities, this treatment involves four basic steps: normalized after grinding; hardened when the piece is almost finished with a medium polishing, sub-zero treatment to precipitate the retained austenite and complete the hardening, and finally one or more tempering to ease tensions and lower the hardness to the desired values.
The qualities achieved will depend on the tests that have been made with each steel and the strictness with which they perform the process that has achieved the best result.

Diamond powder
Support with three Arkansas stones of different grains, coarse, medium and fine.
Pocket sharpener. Useful and practical.

In our case we want is to hardened the blade so that its cutting edge is more durable.
A harder cutting edge will have a more lasting, but spend more time on his resharpening. With a lower hardness will recover the cutting edge quicker but also lose it very rapidly.
The hardness that the great masters have been established as the most balanced is 60 Rockwell “C”.
With this hardness we have very good durability cutting edge and not be very difficult resharpening. Until that blade hardness, we can sharpen with a good natural stone or a steel sharpener of thin grooves.

Test piece of ATS 34, hardened to 61 RC which has exceeded the bending moment and has been deformed without breaking. Below another test piece: SAE 5160, that has broken after having achieved a significant deformation.

There are also sharpening stones and ceramic sharpener, or better yet, diamond dust. With these elements (ceramic or diamond dust) can resharpening a knife easily hardened to over 60 RC.

It may appear that the solution for best performance is simply to harden all blades to 60 RC. It is not quite that simple. The higher the hardness the greater the brittleness and greater likelihood of breakage or cracking. For that reason most of the knives do not exceed 57 or 58 RC. Anyway we have seen many knives broken or cracked on its cutting edge.
The test pieces that I hardened with blades, show that my knives do not break without previous deformation. I full guarantee it.

With these and other tests demonstrated again that it is possible to hardened the blade to 60 RC, without risk of breakage.
A good hardened blade must flex (within the limits permitted by its thickness) without risk of breakage and pass the elastic limit to arrive the deformation without breaking (as in the sample picture on the left).
This knife (Mod. 38) is twisted without breaking, by prying nailed on something hard, maybe a bone or a joint, although it is “fully hardened”, ie “side by side” to 61 RC of hardness.

The right photo shows a jagged knife. Says the article published in the journal Blade of August 2000, signed by Ed Fowler, that Schempp, after successfully cutting the ropes, and win the competition in the Oregon Knife Show in 1999, dented knife trying to cut branches a task for which the knife was not prepared. I agree that a knife prepared to cut rope is not suitable for axing branches, not to have the structure and proper angles, but would not rule out that the thermal treatment also has any effect on the result.

In my conference at the Expo Arms 2001, discoursing on the importance of angles and hardness, with this knife cut 30 or 40 times hemp ropes 1 inch and the same number of pieces of sole, few empty cans of soda and without re-sharpening the cutting edge, the blade intact was “shaving”. Its blade is extremely thin concave, of SAE 52100 steel, hardened and tempered with a hardness of 61-62 RC. The knife belongs to the private collection of Colonel. J. B. Dagger.