Thread: Razor Info From Arthur Boon-part 1.

PERSONAL OBSERVATIONS ABOUT STRAIGHT RAZORS AND STROPS
by Arthur Boon
INTRODUCTION
Starting its evolution as a scraping stone a thousand years ago, the straight razor gradually developed into what proved to be one of the most perfect and simple instrument designs of all times. The weight is very well balanced, the blade is easy to clean and thus extremely hygienic, and the blade geometry is designed to conserve an ideal edge with relative little equipment and effort for many decades, even generations, as a well treated straight razor has an almost unlimited life. Also, when the skin has adapted to the change, the superficial peeling effect of the straight razor makes it suitable even for the irregular skin that suffers from the irritations caused by electric or safety razors.
Little practice is needed to switch to the straight razor for the rest of your life, and to discard the alternative messy compromises as just nonfunctioning make-believe products of fast consumerism. Then what caused the decline of straight razor use? One of the factors contributing to that has been the inappropriate knowledge about maintenance among users but also among manufacturers and designers, which coincided with the upcoming market consisting of pseudo-user-friendly gadgets such as autostrops, rotating razors, and safety razors. This unnecessarily caused the straight razor to function far from optimal, and therefore comparable with the new inventions, which of course was the beginning of the end. Also, ghost stories about supposed dangers to damage the vital vessels in the neck made the picture complete, although a highly polished push cutter has far from relatively little slicing capabilities, and a home full of stabbing and dull cutting tools presents a much higher risk to playing children and pets than a clasp razor stored in a box on the upper shelf in a cupboard.
At present a few manufacturers each produce a few thousand straight razors a year, with some emphasize on collectors' items, a number that slightly increased in the nineties. The dedicated user faces the impossible task to collect contradictory information from several more or less reliable sources which all suffer from the fact that almost nothing of the theory which came down with generations has been published for future reference. In fact, the art of straight razor use and care is an example of lost knowledge. The purpose of this document, is to present a forum for discussion and conversion of knowledge on this topic, in order to reintroduce this 'non plus ultra inder Hand des Selbstrasierers'.
I owe much to the enthusiasm of mr. J. Schremml wo gave me a guided tour at DOVO/Bracht Stahlwaren, Solingen, Germany in February 1999, showing me the production, hollow grinding, and honing techniques. Mr Schremml also borrowed me the original and last pre-world war specimen of a study book on this topic, referenced below. Further, I got information form video's and books, indicated in the references below, and from users who shared experiences on rec.knives.
DESCRIPTION OF STRAIGHT RAZOR ANATOMY Orientation used in the description: the handle to the right, blade to the left, cutting edge pointing downwards. Kopf/Point/Bout/Punta: the left end of the blade. Blade, with a Ruecken/Back/Dos/Lomo, the part of the blade opposite the cutting edge, and a Schneide/Cutting edge/Tranchant/Corte (pointing downwards). Erl/Tang/talon/Espiga: the complete non-cutting metal part fixed to the blade, serving as a grip for the index, middle, ring, and little finger. Doppelansatz/Double stabilizing piece/Double piece stabilisatrice/Doble pieza estabilizadora: two close parallel vertical rims situated where the tang continues to the cutting part on the knife. Sometimes there is only one stabilizing piece. Kranzangel/Decorated tang/Talon decore/Espiga decorada: some sort of art where the blade stops and the tang begin. Schale/Handle/Manche/Cacha: the the part of the razor that contains the blade when closed. Sometimes it has an Einlage/Inlay/Marque/Marca (text, mark on the handle). Steg/Center plug/Rivet central/Remanche estabilizador: the middle plug on the handle; Hohlung/Hollow ground/Evidage/Filo Concavo: the biconcave form of the blade in transection view. Goldaetzung/Gold etching/Gravure doree/Grabado dorado: the mark or text on the blade. Zeichen/Trade mark/Marque/Marca, the mark/text graved on the tang. The Ridge/Der Wall: parallel to the back and the edge, running from point to the stabilizing piece, is a thickening of the blade, the purpose of which is to stabilize against torsion in the horizontal plane, and to give the edge elasticity. The stabilizing piece gives the blade torsion resistance in the vertical plane. If the ridge is close to the edge, it is called =BC hollow ground, the lowest grade of hollow ground; if it is close to the back, it is called 1/1 or full hollow ground; =BD and =BE are in-between. More on grind types below.
TYPES Flat and hollow-ground: Derbes Messer/Flat ground/Le rasoir plein: the cross section of the blade is a triangular shape; Hohl/Full hollow ground/Creux/Concavo: biconcave cross-section; Something in between (1/2 or =BE hollow).
BLADES Round point/Rundkopf: the point is rounded. Square point/Gradkopf: the point is square, forming a spike at the transition between point and cutting edge. Something in-between: Franzkopf Blade sizes (width) are: 3/8", 4/8", 5/8", 6/8", 7/8".
PRINCIPLES OF STRAIGHT RAZOR GEOMETRY In the beginning straight razor blades were wedge shaped, the sides of the blade were straight lines, not concave (hollow). These blades shaved as perfect as the later hollow ground blades, if sharp, but had some disadvantages. First, they were heavy, compromising balance. Second, due to the wedge shape, the sides of the blade above the cutting edge instead of the edge itself, primarily touched the hone surface while honing. Third, after years of daily use, the regular honing caused rapid thickening of the edge width, thus making sharpening increasingly difficult and time consuming. Therefore, the next step was to clear the blade sides from the hone surface, in order to reduce weight, and to use the back as a guide for keeping the correct angle of the cutting edge, with which it forms one plane. This was done by grinding away metal between the cutting edge and the back with a wheel, resulting in a biconcave, hollow ground blade (at first without a ridge), combining an extremely thin blade with a very small cutting angle under 15 degrees. The disadvantage of this second step without a ridge was, that the ultra thin biconcave blades were unstable in the direction perpendicular to the plane of the blade. Therefore the third step was to create a ridge parallel to the cutting edge, dividing the blade in two parts: an upper part between back and ridge, and a lower part between ridge and cutting edge. The ridge is created by grinding the raw triangular basic form with successive different wheel diameters: the greater wheel for the part between ridge and back; the smaller wheel for the part between ridge and cutting edge.
The result consists of two hollow grind blade divisions separated by a thicker ridge, with hardly visible smooth transitions. The closer the ridge is to the back, the more the type goes from =BC to 1/1 hollow grind. The ridge presents stability and vibrations which add to cutting performance, which can be identified by transversely rubbing the thumb carefully over the edge, causing a ringing sound. The ridge is not that thick that it touches the hone, of course, and you can hardly see or feel it. The three parts (two concave parts separated by the ridge) are identified under a sharp light: the ridge diverges the light and is therefore identified as a linear shadow, parallel to the edge. The full hollow grind blades have the ridge at about a little below halfway between back and edge; lower grades of hollow ground just behind the edge, or somewhat further to the middle of the blade. A full (1/1) hollow ground blade keeps a very thin edge even after a lifetime of honing and stropping; a =BC ground blade edge rapidly thickens after years of honing, because of the proximity of the ridge to the edge.
RECOGNIZING A double stabilizing piece (two vertical rims between tang and blade) implies 1/1 (full-) hollow ground, but some full hollow ground blades have no stabilizing pieces at all, but instead a smooth transition between blade and tang. Theoretically, you might confuse a single stabilization piece (which indicates less than 1/1 hollow ground) with these types of full hollow ground blades but there is a difference which can be seen with the full hollow ground Bismarck or Renaissance (DOVE) types of blades. The Bismarck shows a smooth transition between blade and tang, lacking any rim, and therefore is easily identified as full hollow ground. The Renaissance has one rim, which might indicate either less than 1/1 hollow ground (cheaper) or full hollow; the fact that the rim is ot confined to the blade, but runs through into the tang, identifies this type as full hollow ground. If the transition from tang to blade shows one vertical rim that is confined to the blade and exactly vertical, it must be a flat ground or =BD-3/4 hollow.
PURPOSE OF TYPES In general: the higher the grade of hollow grinding, the easier it is for the customer to keep the blade in perfect condition with relative ease (stropping and sometimes honing). Flat ground: in general for heavy and less perfect shave, for contour shaving, hospitals, etc. Full hollow ground for thorough and precise shaving. 3/8", 4/8": hospitals, eyebrows, and a very soft beard. 3/8" and 4/8" are mostly flat or half-hollow- ground. 4/8", 5/8": preferred for daily shaving, specially 5/8" which has more torsion resistance. For persons with very large hands and/or handicap the 6/8" and 7/8" were originally designed, but they also have very good torsion resistance and shaving characteristics.
BLADES MATERIALS Blades are made of normal steel with a carbon-content of 0.6% or more, and of rust-resistant chromium-steel. Carbon steel is easier to sharpen but more brittle, liable to chipping off and staining. Stain-resistant steel takes longer honing, but the results hold longer, and the edge is less vulnerable.
HANDLES MATERIALS Ambonia, Celluloid, Bone, Pakkawood, Mother of pearl, Ebony, Buffalo horn, Plastic. Celluloid is flammable and spontaneous inflammation has been described at higher natural temperatures. Even now, celluloid production is associated with extreme safety measures. Buffalo Horn can deform after some time, increasing the risk of edge damage when closing the knife: it has form memory, but for the wrong form. Mother of pearl is brittle, which might result in cracks soon. Plastic is very thin and easy to deform, causing increased risk that the edge touches the handle while closing it. The hardwood handles do not rot because they are highly impregnated with resins; the weight gives ideal balance. Bone is stable as well. Both pakkawood, snakewood, and bone are have the best material properties for intensive use.
continued in Part 2.