Glossary Tool-Steel

Glossary Intro and Glossary Annexes

Tool-Steel

[this entry is in progress -- 12-1-10]

Different types of steel are used to make the cutting parts of tools such as the "Irons" of Hand Planes, Hand Chisels, Shaper Cutters. high-speed steel (HSS) is a mix — called alloy— with other ingredients, to create metals that hold a sharp edge under the heat and pressure of operation. Steels labeled HSS can incorporate a variety of combinations, created according to the qualities desired for a tool.

image of steel tools manufactured by stanley tools

(The image, left, by Stanley Tools, Division of Stanley Works, New Britain CT, shows a selection of woodworking tools manufactured from different types of Tool Steel.)

Henry B Allen, an engineer for Henry Disston and Sons in the 1920s and 1930s, gave a 1930 paper, in New York, to the Fifth National Wood Industries Meeting, American Society of Mechanical Engineers. For the entire article, click here: Improvements in Steels for Wood-Cutting Saws and Knives

In his first paragraph he states,

The two important factors in a review of steels used for sees are the blade which carries the teeth and the teeth themselves. The steel for the blade, after heat treatment, should combine high elastic limit, good ductility, resistance to fatigue cracking, resistance to impact, and uniformity. There is little in sight to promise further marked improvements in the solid-tooth type of saw. The next logical step is to use inserted teeth made front materials known to be well adapted to the function of cutting wood. This same forward step was taken years ago in metal cutting. Future changes in design, so as to put to use metallurgical discoveries, will require the best. thought of saw user, machine builder, and saw maker. Research and untiring effort alone lead the way to accomplishment.

Tool steel quality is designated with combinations of numbers and letters, like 01, A2, and D2. All have different ratios of Carbide content. (See also Carbide Tipped .)

For example, M2 -- often specified for turning tools -- combines tungsten, molybdenum, vanadium, and chromium with high-carbon steel. There is less need to sharpen an M2 HSS tool as often as a carbon steel one.

The claim is that A2 steel is harder to sharpen than 01 steel. Or that the edges of 01 steel cannot be made as sharp as edges of A2 steel, but A2 steel holds its edge longer than 01. The reason: A2 and D2 steels are tougher than 01 because of their higher carbide content.

Tool steels sort out according to carbon steel or high-speed steel (HSS). HSS tools cost more, but hold an edge longer. HSS is recommended for most Turning Tools, especially Bowl Gouges, Scrapers, and Parting Tools. [Still need more on Rockwell hardness number -- this will come when i upload jpg images from Allen's paper, cited below.] See also High Speed Steel.

Sources: James T. Frane, Encyclopedia of Construction Terms, Carlsbad, CA: Craftsman Book Co., 1994, page 362, covers workability, heat treatability, water hardening, shock-resistant, cold-work, hot-work, and high speed tool steels; Larry Johnson, "What's the Deal on Steel?" Wood Magazine issue no 59 February 1993 page 65; [Anonymous], "Taking a Look at Tool Steel," ShopNotes 15, Issue 90 December 2006, pages 12-13; in C. P. B. Shelley. Workshop Appliances, Including Descriptions of Some of the Gauging and Measuring Instruments, Hand Cutting Tools, Lathes, Drilling, Planing and Other Machine-Tools Used by Engineers Sixth edition, revised and enlarged London: Longmans, Green, 1883, Chapter XI, pages 314-339, is "On Tool Steel and Its Treatment". Henry B Allen's 1930 paper, "Improvements in Steels for Wood-Cutting Saws and Knives ", delivered in New York to the Fifth National Wood Industries Meeting, American Society of Mechanical Engineers, is brief and enlightening, especially from the perspective how, at that time, carbide-tipped teeth on circular saw blades became an obvious needed way of improving the cutting power and standards of sawing wood.