, Sept 3-13,1952 Chicago, Illinois, need page no] argues that "records indicate the use of steel articles prior to 1200. B.C."
Appendix 6: Evolution of Woodworking's "Cutting Edges"
Working notes and images for a conceptual framework of the origin and evolution of cutting edge assemblies in hand and power machinery toolsDisclaimer: this piece is not intended as a "history"; instead its intent is to set out a brief account of how I understand the cutting edge of woodworking tools evolved.
Moreover, recently -- about three years after the Evolution of Woodworking's 'Cutting Edges' concept occurred to me -- I discovered a chapter in an almost 50-year old book, by James J Hammond, et al, "Topic 40: Theory Underlying the Design and Action of Cutting Tools", Woodworking Technology Bloomington, IL: McKnight and McKnight, 1961, pages 92-95. The gist of the chapter -- and much of the book's contents -- focuses on a "theory" that, essentially, woodworking tools do one major operation: cut and/or shape wood, basically, the same as what my theory is, as outlined in the narrative below, but more fully developed. I say "more fully developed" because Hammond and his co-authors -- all talented instructors in the Industrial Arts movement -- buttress their arguments with evidence that includes well-drawn, clear, schematic diagrams that show the cutting and shaping functions of major hand and power woodworking tools. I have reproduced several below.
Well, shall I cry? Or, laugh? Cry, because my theory wasn't as original as I thought it was. Instead of "inventing the wheel", I end up "re-inventing" the wheel.
I can laugh, too, though, for at least two reasons:
first, this book confirms the validity of my theory, which I find consoling. Nothing like being out on limb with a theory that everybody views with suspicion.
Moreover, as good as the Hammond, et al "Theory Underlying the Design and Action of Cutting Tools" is, as you'll note below,
second, I found reason to question part of their "theory", specifically their claims about the operation of the "knife wedge". For me, their ideas about the "knife wedge" merely constitute a variation on their "chisel wedge". Their claims about the knife -- as a "double bevel" wedge -- does not have enough distinctiveness to stand alone.
Moreover, throughout their narrative, as an example, the authors only mention "knife wedge" once, and in that particular context, knife wedge figures only in a minor way.
But, I am jesting. As amateur woodworkers, we are not in a competition. Instead, for us, more than anything else, woodworking is "fun"; if it wasn't fun, to occupy our leisure hours, we would find some other hobby that really was fun.)
First, as I note at the top, much of the bibliography for the existing scholarship on the history of early hand tool development exists in anthropology and the history of technology.
(Have yet to search Technology and Culture intensively yet, but my initial foray into it was disappointing: it's annual bibliography is arranged in a highly classified order, but strangely this classification scheme lacks a category for woodworking, which means that to pick up articles on woodworking, you must go to the index and look individual topics. Have yet to look for a digitized database version of it.) History of technology is especially useful because they published an annual bibliography since 1964, and its digitized, but my academic library doesn't subscribe to it.)
Conceptual Framework: Woodworking as an Evolving Art and CraftFor readers not familiar with either the objects or the vocabulary of woodworking, I offer this section as an "introduction" of this online book. As both a craft and an art, woodworking traces back to the earliest points of man's habitation on earth.
By beginning with the birth of woodworking, we can show the connectivity that traces through these beginnings to the present day. I especially want to impress you, the reader, about the empirical and experiential aspects of woodworking, its intuitive sweep, and the "bottom up" nature of its development. Woodworking is, in truth, one of mankind's most admirable achievements. The text and illustrations below introduce some basic woodworking concepts.
My intent is simple: explain how woodworking tools function when cutting and shaping wood. And to make these concepts clear, the ideal perspective I believe is one that shows their evolution from rudimentary tools that helped primitive humans survive and -- increasingly -- flourish.
Except for the initial chisel, all tools introduced in this section exhibit one characteristic, i.e., cutting with multiple sharp edges.
Evolution of Woodworking's "Cutting Edges"
1. Single Wedge-Shaped Cutting Edge: 1. The Chisel 2. Multiple Wedge-Shaped Cutting Edge: 2. The Toothed Saw 3. Single, Elongated Wedge-Shaped Cutting Edge: 3. The Hand Plane 4. Single Cutting Edge, Elongated, Profiled Wedge-Shaped Edge: 4. The Profile Plane 5. Multiple Cutting Edges, Rotary Action, Short Wedge-Shaped Cutting Edge: 5. The Drill Bit 6. Multiple Cutting Edges, Rotary Action, Short Wedge-Shaped Cutting Edge, Straight Edge: 6. The Circular Saw Blade 7. Multiple Cutting Edges, Rotary Action, Elongated Blade, Wedge-Shaped Straight Edge: 7. The Jointer and The Planer 8. Multiple Cutting Edges, Rotary Action by External Power, Elongated Blade, Wedge-Shaped Profiled Edge: 8. Router Bits, Shaper Cutters and Jointer and Molding Heads
My narrative begins with the theory underlying the operation of woodworking's cutting edge. Then, to illustrate, walks through eight stages -- more-or-less successive, historically -- in the development of woodworker's cutting edges.
The narrative covers (1) the chisel (single wedge-shaped cutting edge), then progresses through (2) the toothed saw (multiple wedge-shaped cutting edges), (3) the hand plane (single, elongated wedge-shaped cutting edge), (4) the molding plane (single cutting edge, elongated, profiled wedge-shaped cutting edge), (5) the drill bit (6) the circular saw blade (multiple, short, cutting edges, rotary action, narrow wedge-shaped cutting edge),(7) the rotary cutterhead (multiple cutting edges, rotary action, elongated blade, straight wedge-shaped edge), (8) the shaper cutter, the router bit, the molding knife (multiple cutting edges, rotary action, elongated blade, profiled wedge-shaped edge).
Along the way, I will offer definitions and illustrations.
The Theory Underlying the Operation of Woodworking's Cutting EdgesIn "cutting" and/or "shaping" wood — whether it's sawing, planing, boring, shaping, routing, sanding — the purpose of the operation is to systematically sever material along a workpiece's length, width, or thickness.
1. Every wood cutting tool is a wedge-shaped cutting edge or series of wedge-shaped cutting edges, with a single bevel.
Chisels, plane irons, turning tools, gouges, drawknives, spoke shaves, scrapers -- and sandpaper -- are all modified chisels or gouges, with single wedge-shaped cutting edges, as are jointer, router, shaper, molding, and thickness planer knives.
The two wedge-shaped cutting edges of an auger bit are, in effect, two chisels set up with the blades pointing in opposite directions -- see below. When the bit is rotated, the "lips" cut in a clockwise direction. The twist drill has its cutting edge on an angle, but the effect is the same.
In the case of a tool like the cross-cut saw, the double bevel on each tooth, in effect, makes two wedge-shaped cutting edges See below .
2. In cutting wood by any method, stock is removed through the shearing action of the wedge-shaped cutter or series of cutters. The wedge-shaped cutting edges shear the fibers of the workpiece, and -- as shown in the image on the left -- the incline of the face of the wedge causes the fibers to be separated from the workpiece, producing shavings, chips, or dust.
3. The shearing is accomplished by the cutting edge of the blade (or teeth) being wedged into the stock in a sliding motion, and at a depth controlled by the tool's operator.
4. The wedge or wedges are driven by hand or machine power and engage the stock in a given plane, arc, or angle.
5. The wedge-shaped cutting edges may be pushed or pulled into the workpiece-- as with a Radial Arm Saw's rotating blade --, or may revolve or reciprocate in the workpiece -- as with a Lathe or Jig Saw, or the workpiece may be pushed into or revolved against the wedges -- as with a workpiece fed into a Table Saw's rotating blade or a rotating log sheared into veneer sheets.
6. The smoothness of the cut is determined largely by the shape and content of the wedge-shaped cutters -- carbide teeth, the number of wedge-shaped cutting edges -- an 80-tooth carbide-tipped blade, the angle at which it is inserted into the stock, the depth of the cut, the moisture content, and the grain pattern. The smoothest cuts usually result in shavings. (Under a microscope,the finest sawdust appears as minute shavings.)
7. The most effective angle of approach of the tool's cutting edge to the wood fibers is approximately 30°, and each type of tool is so designed that in use, the wedge-shaped cutter's edge enters the stock at that approximate angle. At certain angles the wedging action is erratic because the cutting edge of the tool tears and breaks the fibers ahead of the cut.
8. The lip clearance is the relief given the wedge-shaped cutting edge so that it may enter the material to be cut. Much of the effectiveness of the cutting edge depends on the correct lip clearance angle. If no clearance angle was provided, the cutting edge would be prevented from entering the work. Too great a lip clearance angle weakens the cutting edge. The angle may range from 6° for metal cutting tools to 35° for woodworking tools.
9. The rake angle is the angle at which the face of the cutting edge enters the work. This angle partially controls the tightness with which the shavings are curled. A large rake angle requires a great force to drive the tool. Too small a rake angle results in a thin cutting edge. Tools such as the plane, auger bit, and saws are designed by manufacturers for maximum stiffness and most efficient cutting angle.
(The images above and the text are adapted from "Topic 40: Theory Underlying the Design and Action of Cutting Tools", James J Hammond, et al, Woodworking Technology Bloomington, IL: McKnight and McKnight, 1966, pages 92-95. Pages 92-93 have illustrations of the operational physics of the hand scraper, the rip saw, cross cut saw, the auger bit, and the combination circular saw tooth.)
(1) The Chisel: single wedge-shaped cutting edgeMan began fashioning tools at least a half million years ago (Jones and Simons, 1961). In man's long history, estimated to stretch 20,000,000 years, the use of chisels, however primitive, come into evidence very early. (C. D. Darlington, Evolution Of Man And Society, 1969, page 22; The Story of the Saw, a 1961 publication issued by the saw blade manufacturer, H. Disston, and Sons Inc., also informs my account of multiple cutting edges. The authors are Peter d'Alroy Jones and E N Simons.)
As specialized woodworking tools, the anthropologist, W L Goodman, The History of Woodworking Tools, 1964, citing numerous sources, shows that the chisel, the axe and the adze, trace back to the Stone Age, i.e., about 50,000 years ago. (Goodman, pp 12ff, 195-198).
Refinements on the chisel followed. In early classical times (i.e.,,, period of Roman Empire), at about the beginning of the Christian era, a cutting tool which could be easily adjusted and which depended less on the skill of the craftsman plane, was in use. (Figure 1) Although no examples are extant, tradition suggests that the tool dates back to the Greeks. (Goodman, 39-109).
Before 1200 BC, tools used as chisels consisted of flint or other similar, naturally occurring, hard substances. But, in his conference paper, "Development of materials for wood-cutting tools," E. K. Spring, [Chief Metallurgist, Henry Disston & Sons, Inc., Philadelphia, Pa. Proceedings Of The Wood Symposium: One Hundred Years Of Engineering Progress With Wood, The Centennial Of Engineering Convocation
(I also consulted H., Disston,
and Sons. The Saw In
History. 8th edition. New York,
1926. The era in which these developments about "sawing"
occurs, the "pre-metal age", is labeled the Neolithic Age,
ca. 4700-2000 BC. Neolithic
is a term coined
in 1865 by the Englishman, John Lubbock, but given more
validity in 1925 by the English archaeologist, V. Gordon Childe,
European Civilization, 1925. The
Neolithic Age is characterized as the period when man mastered the
processes required to supply his own food, through domesticating
animals and cultivating plants, and skills in fashioning
Neolithic man adapted as tools the objects he found around him; as an early form of the multi-toothed saw, for example, really just a variation on the chisel, the Neolithic man cut crude and uneven notches or serrations in the edges of flint flakes. For more background on the Neolithic Age, see ch 4 of Darlington, The Evolution of Man and Society, 1969.)
The action of a single tooth in a saw is represented below, in this diagram adapted from W F M Goss, Bench Work in Wood, rev ed, 1905, page 30, but for greater detail, click here.
Ancient man, driven out of necessity -- survival -- his imagination limited to found objects, but pragmatic, empirical -- education not needed -- visualized in due time, that, simply by multiplying the "edges" of a chisel multiplied geometrically the efficiency of the chisel for cutting and shaping wood and stone.
And crude though they be, very slow and laborious in action, acting like multiple chisel edges, the saws make their appearance in the Copper or Early Bronze Age. (W L Goodman, 110-159). Says Goodman, "It is fairly obvious that only a metal saw would have any advantage in working life and economy of material over the existing stone axes and other cutting tools," and consequently the first real saws evidently were created ca 1490 B C, in Egypt.
In these images of the action of today's crosscut hand saws, the wedge-shaped cutting action occurs in two distinct directions:
(1) back-and-forth, where, the side points on either side of the saw -- the first set of wedge-shaped cutters -- score parallel lines. This action is wedge-shaped cutters operating in a back-and-forth motion.
(2) As the sawing action continues, the cutting edge on the inside of the teeth -- the second set of wedge-shaped chisel cutters -- comes into contact with the wood, shearing it out of the kerf.
When a full bite is taken, the points of each tooth score the outsides of the kerf, and the sharpened, beveled sides of the teeth, wedge-shaped, shear the wood between the side wedge-shaped cutters.
In the cross-cut saw, the teeth are set, alternately, to the right and left, so that the cut, or kerf, is wider than the thickness of the saw blade. This off-setting of the teeth is known as "set."
(Editorial Note: These images are adapted from James J. Hammond, et al, Woodworking Technology Bloomington, IL: McKnight and McKnight, 1966, 2d ed., pages 96 and following. However, in opposition to Hammond and his co-authors, who claim that the "scoring" of the back-and-forth action is a "knife wedge", rather than a "wedge-shaped" chisel, I claim that the back-and-forth action is "wedge-shaped" cutting, a conclusion drevied from an analysis of the "point" on each tooth. Rather than having a "knife" shape, for me, the point of each tooth is the point of a "wedge". A knife's elongated edge is distinctly not a point. However, such differences of opinion are merely that, differences of opinion, and need not become an obstacle to understanding how saw teeth operate as wedge-shaped cutting edges.)
[not yet completed] One of the greatest single events in the history of mankind — the invention of the wheel — may well not have been possible without the earlier invention of the metal saw.[Vere Gordon Childe New Light on the Most Ancient East 1952 "wheel can hardly be made without a metal saw Page 110; JJones and Simons story of the saw 1961 selections.doc] forbes, r j, studies in ancient technology, 1955 and tunis, Edwin, wheels, 1955]
The Romans, for example, employed a variety of planes, including ploughs, rabbet planes, hollows and rounds. In the medieval period, much shaping of work was achieved with molding planes, while in the 15th and 16th centuries, the linen-fold panels [get picture], very popular, needed to “have been worked with sets of hollows and rounds, and the panels themselves let into ploughed grooves or rebates. The lathe, or turned work, uses straight- and curved-edge chisels. Turned work appeared in the eastern Mediterranean in the second millennium B C. While there evidently no lathe artifacts of this period, speculation suggests that power was created by the bow-drill, “in which the object of be turned was the stock of the drill, rotated by a bow between two fixed points."
James J. Hammond, et al, Woodworking Technology Bloomington, IL: McKnight and McKnight, 1966, 2d ed., pages 92 -- the physics of the plane's components are set out: the rake angle, the cutting angle, the lip clearance.
This lock-edge assembly is a smooth-edge slot, but the preference is for
serrated slots, because they allow precisely setting the cutters, so
that the cut each makes is uniform with the other, and one cutter is
not doing all the work.<
On the right -- courtesy < oella_saw_and_tool -- is an image of the lock edge with the serrated grooves, allowing precise setting of the two cutters.
On the left is a three-edge bead router bit.
[note to self 8-22-08] Nathan Rosenberg's ch
America's Rise to Woodworking Leadership
should be used as part of a theme setter. WWU book, Brook
America's Wooden Age: Aspects of Its Early Technology
, 1975: pp 37-62, 197-202; Rosenberg also wrote the 86-page intro to
the reprint of the American system of manufactures, originally
published in 1855, and 1854. The following is a scan of rosenberg's pp
38-39 – but the whole ch should be copied.
Techniques for cutting and shaping wood continue to evolve. The discussion above is limited to the cutting edge.
Another method of shaping wood is Sandblasting (although like the action of sandpaper itself, particles of sand actually "cut" the wood).
However, Lasers are
used for cutting and shaping wood, and achieve this action without a
cutting edge. lasers are the tool of the future, for certain, but it is
unlikely that lasers will entirely displace the cutting edges discussed
Sources: (not complete) Vere Gordon Childe New Light on the Most Ancient East 1952; W L Goodman, The History of Woodworking Tools London: G Bell, 1964; page 105; Cyril Aldred, “Furniture: To the End of the Roman Empire,” in Charles Joseph Singer, et al, eds., A History of Technology, v2, Oxford University Press, 1956, page 232; Garrett Wade, Tools New York: Simon and Schuster, 2001