The following are excerpts from an article published in Woodwind Quarterly, August, 1993, written by Scott Hirsch and entitled, ACRYLIC WOOD STABILIZATION, THE IMMORTAL INSTRUMENT:
I get asked this kind of question a lot lately and I also hear things like, Jeez Damascus is a lost art, isn’t it? Or Damascus is sharper than ordinary steel and on and on. Well these are valid questions and can not be answered in a few words like yup sure is or nope it aint.The problem of a short answer is also due to, what is Damascus steel?
Many folks have heard the term Damascus, have heard of Japanese swords and have been subject to some misleading information along the way. I sometimes hear people say things like; Samurai Japanese swords are folded a million times and can cut machinegun barrels. Or how about the story of the blade that cut the anvil in half that made it. Or the Japanese sword that is so sharp that it will cut a leaf in half upon contacting the sword edge as it floats down the creek. And then there is the old falling silk scarf story. Hey Kevin Costner showed us that one in a movie, right.In a way, I hate to lift the veils of lore and let the bright rays of enlightenment shine in, but some of us are taking these things a little too serious, aren’t we? And yet we can’t help but wonder at times if just maybe there may be a very small glimmer of truth somewhere in one or more of these tails.In June of 2002 I held a Damascus symposium here at the shop and one of the featured speakers Dr. Sung Beck is a Grandmaster Swordsman.
He delighted us with his exquisite collection of Chinese and Japanese swords and also with his finely tuned wit and story telling abilities.His humorous stories had a point though, pun not intended, and gave us just a little insight as to what it was and is all about. His stories told us how to straighten a bent Japanese sword by banging it over a log or using a monkey wrench and how to pick out a good one for battle; they were truly enlightening and gave us all something to think about. Dr. Beck made many comments from his observations from his past training of cutting numerous things for practice with Chinese and Japanese swords over the years and some of them made perfect sense and others I will have to think about for a spell.OK, before we get rolling let’s start with just a smattering of background to pave the way. Damascus is a place in Syria and is where westerners first observed the famed swords of the Far East. Actually they were made in India from a steel called wootz and only discovered in the city of Damascus. Wootz steel is melted in small sealed clay crucibles from steel scraps and carbon bearing materials and after solidifying, were then forged at a very low heat into sword blades. Sword remnants tested for content were often found to contain a fair amount of sulfur and phosphorous.
It is believed that this made the cast ingots red short, difficult to forge and is very likely the governing secret to the success of Damascus blades. The higher heats that the European smiths were accustomed to, would have crumbled the steel and it also would not have produced the kind of steel that made them famous. Although the task of forging at such a low and narrow band of temperature was difficult, the first side-affect or benefit was tougher and springier steel with superior edge holding properties. The second benefit was the pattern formed by the ghosting of the dendrites which were formed during the slow initial cooling of the ingot. It was discovered recently by Al Pendray and Dr. John Verhoeven that the trace amounts of vanadium were responsible for forming the Damascus patterns because they aligned along the grain boundaries of the dendrites and due to forging at a reduced heat, retained the image throughout the forging process. Although it was the dendrite pattern that gave rise to the Damascening, they soon learned also how to enhance the patterns mechanically.
During this same time frame the Japanese were discovering the methods of producing fine steel blades from iron ore panned from the rivers. This panned ore was smelted in a wood coke furnace and the crude metal was broken up into pieces, forged flat and stacked into billets. These stacks were forge welded together and forged to length. Then it was folded first length wise and after welding and forging again folded sideways and welded again. This process was repeated from 8 to 16 times in order to refine the impurities out of the steel and to remove excess carbon. If you will get out your calculator, you will find that 16 folds will give you 65,536layers of steel if you start with one single layer, if you started with an 8 layer stack, 17 folds will give you 1,048,576 layers. How many layers would you get if you folded the steel one million times? Now this is assuming that you would have the time or, due to material loss from scaling, any thing left to work with.Now when the sword is forged out of this steel, all of the layers will be lined up and going in the same direction. Any flexing of the blade sideways will be stretching half of these layers and compressing the other half. For sure, this would be as strong and resilient as a modern day forged blade of solid non layered steel. In fact I think that it can be argued that the layered steel would be more resilient because any stress cracking may be stopped as it reaches the next layer. Flexing the sword blade up or down would be the same as any other homogenous blade as each layer is undergoing the same stresses.
Modern day Damascus or Pattern welded steel is manipulated in various ways to produce some very striking looking patterns. Many of these layers will be aligned in such an order as to produce a sound blade, but some of the layers will be running contrary to that which will produce a good blade. In other words some layers will weaken a blade because of an adverse alignment of weld lines. In such a blade, if you flex the blade sideways, the layers do not just stretch or compress, they could pull apart at the welds. A multi bar composite blade or a sanmai blade will have built in factors favorable to the strength of the blade if done in the right way.A many layered blade will likely have weld lines running across the edge and this will give the edge a micro serration edge. This edge will feel sharper than a homogenous blade and will out cut a conventional blade using a slicing motion. By folding the steel billet like a paper airplane, according to Dr. Beck, the Japanese could improve the swords cutting abilities on the tip’s first couple of inches. This is the working part, the rest of the blade is there to put the first two inches into proper reach. He also suggested that the sword could be made to cut either on a forward slice or on a rearward slice depending on the way the folds were made.When you boil it all down, cutting is a function of blade geometry, hardness, toughness, sharpness, micro edge serration and technique. Yes Damascus can be stronger, no it sometimes isn’t.
Yes Damascus does feel sharper and for many cutting tasks will out perform a conventional blade.It is interesting to note that Damascus swords and the Samurai swords had a parallel history a world apart from each other and both had an impact on the rest of the world. It is also interesting that both art forms were very nearly lost, indeed, one had to be reinvented. The modern day Damascus or (pattern welded blade) is a blend of both ancient arts and has taken on a life of its own. According to Dr. Verhoeven, pattern welding predates both of these technologies.Today’s patterns have transcended those of ancient times, but are they as battle worthy? I believe that many modern day smiths have the capability of producing a blade just as battle worthy as their ancient counterparts and better. And yes there likely are a some blades that although very beautiful will not stand up to battle conditions.
If art is truly, “form follows function”, then where does that leave some of today’s stunning looking blades? I would suggest that the really true art form is in both beauty and functionality.
Author: Lyle Brunckhorst
Robbie Farrance investigates the effect of wet and dry sharpening
methods on turning tools, and reveals some interesting findings
One of the first microscopic observations, usually also clear to the naked eye, is the formation of a grinding burr. In the case of a high speed steel tool this is very pronounced if using a dry grinder, rotating towards the work piece, whereby a compacted and hardened burr is thrown up.
Water cooled sharpening
The alternative method of tool grinding used in these trials was by the means of a slow running, water cooled grinder and the sharpening was undertaken with the stone running away from the cutting edge. The leather honing wheel supplied with this equipment was also used,in conjunction with a honing paste. The resultant edge appeared from microscopic examination, to be burr free.
Is a burr beneficial?
Certain schools of thought suggest that with some turning tools this burr is beneficial, but this is not the case. Woodworking edge tools, such as gouges, chisels, planes, etc. work by a wedge cutting action. A keen edge has the ability to penetrate between the layers of wood fibres and anything that interferes with this action is deemed to be detrimental. So a hard burr, thrown over the leading edge of the tool will seriously impair its cutting efficiency. The conclusion has been drawn that this burr is hardened. With gouges in particular, it was found that this burr is extremely difficult to eradicate. Prior to turning with the tool, a slip stone was used to try and remove the burr for a timed period of one minute. This prolonged finishing did not remove the burr and often left its root firmly folded over the cutting edge.
Method of investigation
In order to answer some specific questions as to how sharpening methods may affect the tools, a means of showing the resultant cutting efficiency had to be found. It was finally decided to show how much wood could be removed by a tool in a measured time, over a measured distance, giving a resultant depth or volume of wood removed. The equipment used was a K.E.F. dry bench grinder mounted with an 80 grit white wheel and a Tormek 2004 Super Grind system, in conjunction with their Universal Gouge Jig. Honing was by means of an Arkansas slip stone of medium grade for the dry grind and the manufacturer’s leather honing wheel for the wet grind. To perform the trials, the tools were prepared to the same degree of sharpness, so far as could be judged by edge ‘feel’ and from microscopic observation, before the start of each complete ‘run’. This test was repeated with eight pieces of hardwood and eight pieces of softwood and the results are shown in the graphs. Whilst these trials proceeded, it became clear that the wet ground tool was performing better than the dry ground, both in terms of durability of the cutting edge, and the finished surface of the wood.
The resultant data was assembled in the form of a graph… The wet-ground tool gave the best results on a consistent basis, and far outlasted the dry-ground tool in terms of durability. An odd thing was that up to a point,i.e. three minutes into work time, the dry ground tool seemed to increase its cutting ability. Fall-off in performance was fairly marked after this point. The residual burr, which had proved so difficult to remove with a slip stone, had worn away in use. With this protecting guard gradually being eroded, the tool had in fact become sharper, until the burr had completely disappeared.
Using gouges and chisels, it would seem that a universally far better performance could be obtained by adopting a wet grinding method, in conjunction with honing. It’s generally assumed that using a slow-running water-cooled system will be time consuming, but this turns out to be more supposition than fact. The initial grinding of the tool to shape (profiling) can take longer but, once this is achieved, subsequent grinding is simple, quick, and more to the point can be repeated with a good degree of accuracy. Adopting the wet system does in fact result in a sharpened edge, in the accepted sense,not just acoarse-ground bevel.
The wet-grinding method leaves apolished, burr free edge without any overheating of the tool. This polished surface creates less friction in use, thus aiding the durability of the cutting edge. Due to less frequent sharpening with wet grinding, the tool life is significantly prolonged, since less material is removed. The dry grinding method leaves a hard compacted burr, which is very difficult to remove. The evidence suggests that using a wet-grinding method gives a sharper edge and cleaner cuts with more than double the effective turning time between sharpening. From the graphic
data, it can be seen that, even after 18 minutes of continuous turning insoftwood, the wet-ground tool was still cutting more than three-and-a-half times faster than the dry-ground tool.
Robbie Farrance has spent a lifetime
working with wood and its associated
subjects, and became a full time teacher
of wood-trades some 12 years ago. He
holds many qualifications including H.N.C.
and is a National Assessor. Currently
employed by the Royal National Institute
for the Blind, it is for his work in pioneering
methods of teaching blind and partially
sighted students, that he has gained
national and international recognition.
The following are excerpts from an article by Michael Thompson written for the March/April 1991 issue of Blade Magazine entitled ANY WOOD FOR A KNIFE HANDLE:
A nagging problem with some handle materials, especially ivory, horn and wood, is a tendency to shrink and warp because of different humidifies in various parts of the country.The solution is to stabilize the applicable handle materials so they can’t dry out.Two-part process requires applying acrylic resins to a handle material followed by a curing period. The result is a water-resistant, harder-than-untreated wood that can be machined and drilled, and that can be polished to any finish you’d put on steel, from satin to a high gloss.Before, knife makers were limited to a few hardwoods when they wanted burled or fancy grained wood handles. Now even soft woods can be stabilized and used as knife handles. I have a piece of California buckeye that is soft enough that I can dent it 1/8 inch with my thumbnail. After stabilizing it is hard as counter-top material and takes a great polish that was impossible before treatment.
Spalted maple is one of the more impressive of the soft woods that can be used for knife handles. It’s unusual because of the dark streaks that develop as the wood begins to decay, thus the word “spalted”. After treatment this otherwise useless wood makes one gorgeous knife handle.Various woods react differently to stabilization. Soft woods absorb greater amounts of the chemicals and are consequently more affected by the advantages of the treatment. Box elder burl, a highly figured soft wood, could not be used on a knife handle until the advent of stabilization. Other species like spalted cotton wood, myrtle wood burl, redwood burl, maple burl and pipe briar may now be machined and used for knife handles, including those on interframe folders.For some reason the stabilizing chemicals seem to displace the natural oils in cocobolo and a few other hardwoods, including some samples of walnut, which results in the natural oils “weeping” out of the wood for days after the treatment.Since stabilized wood repels water and oils, stains, dyed and chemicals will not penetrate wood.
Stabilization may seem like the answer to most problems associated with wooden knife handles and it often is. But you may not appreciate all of its side effects. I noticed a weight increase of about 20 percent in the wood I had treated. Some woods increase as much as 50 percent in weight if they are soft and absorb a lot of chemicals.Ray Applegate carved some figures into the stabilized wood with excellent results. Stabilization eliminated all moisture from the fibers. The result is that all of the wood’s natural flexibility and elasticity are removed. Forcing pins through small holes will crack stabilized wood, as will hammering on it. But that same inflexibility is an advantage when dealing with other stabilized materials like horn and ivory. Horn and stag can be straightened with heat, then stabilized so that they will not warp back to their original shapes.The natural pores of stabilized woods remain open after treatment. Since no finish is necessary and most knife makers simply sand the wood to 400 or 600 grit, then buff with jewelry polishing compound, some of the compound may be trapped in the open pores of the wood. If this is a problem, stabilized wood can be filled like any other wood by impregnating the open pores with a quick-setting glue and sanding dust from the wood itself. Fred Roe seals the pores with an acrylic before sanding and buffing.Proper sanding and buffing can impart a glossy finish to stabilized wood. But that beautiful polished finish on stabilized wood will dull after prolonged immersion in water. That’s why Leon Thompson uses a hand-rubbed satin finish on knives he expects to be used in and around water.
Stabilized wood will take in moisture by capillary action much like steel wool is waterproof but will absorb water like a sponge. If you put a block of stabilized wood in water, it will become saturated in a few hours. The actual fibers are dry but the spaces will pick up moisture. If you lay the wood on a workbench, the water will leak out overnight and the piece will be dry again tomorrow.This is not an exact science. It’s more of an art. Some examples to illustrate: a ram’s horn that curled even more during treatment, a piece of spalted maple that broke apart, and the odd samples that weep oil. When working with natural organic materials, the innate character of each piece must be considered.Highly figured or burled woods tend to warp during treatment. That’s why its wise to leave extra material on a piece that is being treated.I’m impressed with the possibilities of stabilized materials. Hunting and fishing knife handles can now be made of wood and even horn. Folder scales of exotic wood may now be milled and machined to shape with predictable consistency.No longer will full tang knives have steel extending past the wooden scales after a few years use.Stabilized materials should be worked with fresh sanding belts on conventional machinery or with sharp hand files and sandpaper. they require no finish other than sanding or polishing, and possess the endurance of synthetics while retaining the natural beauty of real wood. the treated woods have already been ordered by dozens of custom knife makers and collectors with reviews ranging from guarded optimism to downright enthusiasm for the product.