HISTORY OF CARBIDE CUTTING EDGES, A THREAD FROM... KNIFE WORLD MAGAZINE P O BOX 3395 * KNOXVILLE TN 37927 http://www.knifeworld.com WHUT IZZIT by Bernard Levine NUMBER 180 DECEMBER 1992 Mr. @@@@@ also asked about the blade marking: ROBESON FlameEdge/ TUNGSTEN CARBIDE/ CUTTING EDGE/ PAT. No. 2714563. He did not indicate [what type of knife this mark is on]. According to Ferguson's 'Romance of Collecting...' book, "FlameEdge [was] a registered trademark of Robeson to identify the only cutlery in the world with a Tungsten Carbide cutting edge. The direct result of missile and rocket research, Tungsten Carbide, one of the world's hardest materials, is detonated on to one side of a knife edge at ten times the speed of sound and at a temperature of 6,000 degrees. This process is patented under U.S. Process Patent 2714563." That patent was granted in 1955. Fitting saw blades, drill bits, and machining cutters with tungsten carbide cutting edges has real practical value. By contrast, I cannot see the benefit of coating one side of a knife's edge with a thin film of the material. It's sort of like chrome plating a tool steel knife blade. Any benefit of the coating is lost the first time that the knife is resharpened. * * * WHUT IZZIT by Bernard Levine NUMBER 182 FEBRUARY 1993 In the December 1992 column, in response to an inquiry about the "ROBESON FlameEdge TUNGSTEN CARBIDE CUTTING EDGE," I noted that "fitting saw blades, drill bits, and machining cutters with tungsten carbide cutting edges has real practical value. By contrast, I cannot see the benefit of coating one side of a knife's edge with a thin film of the material... Any benefit of the coating is lost the first time that the knife is resharpened." Mr. G. T. Williams of Kentucky saw this carbide coating process in operation. He writes, "In the late 1960s I had the opportunity to visit a Union Carbide plant where they were plating metal with tungsten carbide... The base material to be coated was set up like a target and the tungsten carbide was shot out of a device that looked similar to anti-aircraft guns I have seen on naval warships. Since the sound barrier was broken, the process was isolated and the operator wore significant ear protection. "The theory for placing a thin coating of tungsten carbide on one side of a low carbon blank to form a knife is that as the softer steel wears away, it exposes the hard thin film of tungsten carbide, which acts as the cutting edge. A knife of this design is especially important in industrial applications where it is difficult to get to the blade for resharpening," such as the roll paper cutter in the original IBM copier. Mr. Williams noted that on industrial knives, where this process is mainly used, proper sharpening is done at an angle to the tungsten carbide coated surface, so as not to damage the coating. This makes eminent sense, at least in a factory setting, but the average citizen sharpening his pocket or hunting knife would be unlikely to take this precaution. * On the same subject, Sergeant Major William S. Hartling (USA Ret) of Maryland writes, "I seem to remember something about the Robeson FlameEdge knife from the days (35+ years ago) when I used to stand in front of knife displays and drool. If memory serves, the theory behind that process was the same as hard surfacing bulldozer blades on one side only. They were sharpened on the soft side, or [the softer metal was] left to wear away naturally. That way they were self- sharpening. Another thing to consider might be the theory of a very hard cutting edge supported and 'cushioned' by a softer material," as in Swedish hunting knives and Japanese swords. * * * WHUT IZZIT by Bernard Levine NUMBER 184 APRIL 1993 In the December 1992 and February 1993 columns I discussed the ROBESON FlameEdge TUNGSTEN CARBIDE CUTTING EDGE, 1955 process patent 2,714,563. In that process, "Tungsten Carbide, one of the world's hardest materials, is detonated on to one side of a knife edge at ten times the speed of sound and at a temperature of 6,000 degrees." I have seen several descriptions of these knives, but until now I had never seen any dated advertising for them. Mr. Mike Wadsworth of Alabama has one of these FlameEdge knives, and he also has a mail order catalog issued by J(ohn) H. Sutcliffe & Co. of Louisville, Kentucky in the fall of 1963. Page 389 of this catalog shows three "FLAME EDGE SUPER HUNTERS." One is a stag handled skinner that cost $10 (No. 568TC). The second is a leather washer handled hunter that cost $8 (No. 330TC). The third is a Pakkawood handled filet knife that cost $5 (No. 213TC). All three knives are marked with the Kinfolks brand name. Kinfolks Incorporated of Little Valley, New York, had gone out of business about 1951, but its name had been acquired by Robeson, for use on select lines of pocket and sheath knives -- such as this TC (tungsten carbide) line. These were premium priced knives back in 1963, and examples in their original display boxes would probably command a premium on today's collector market, although I have not actually seen one for sale in many years. * * * WHUT IZZIT by Bernard Levine NUMBER 186 JUNE 1993 In the December 1992, February 1993, and April 1993 columns I discussed the ROBESON FlameEdge TUNGSTEN CARBIDE CUTTING EDGE, 1955 process patent 2,714,563, and its use by Robeson on its Kinfolks brand hunting knives. Now Mr. Russell Predmore of Minnesota has sent in photocopies from the 1965 catalog of Fullers Wholesale Tackle Co., Park Rapids, Minnesota. On page 142 this catalog shows the FlameEdge 213TC filet knife, for $4.95 with leather sheath. It has a "Red/Black Hi-Den EZ grip handle." On page 183 the catalog shows two Kinfolks FlameEdge hunting knives: the 330TC with leather handle, for $8.00; and the 568TC with India stag handle, for $10.00. Mr. Predmore has one of the latter knives. ******************* BRL... http://www.knife-expert.com/