Glossary L

Landscape panel

A wood Panel in which the grain runs horizontally rather than vertically.

Source: Home Craftsman 4 March-April 1935, page 172

Lap Joint

see Woodwork Joints

A method of attaching two workpieces, where half the thickness is removed from both pieces, creating a -- a Rabbet -- to form a Joint, with the same thickness as the original.

Lathe

Lathe Chuck

Lineal Foot

[under construction 3-31-09]

Having length only, pertaining to a line one foot long, as distinguished from a square foot or cubic foot or Board Foot. See also Measurement.

Lineshaft Drives

[under construction 11-7-09]

(The following is adapted from Warren Devine): The impact of the shift from steam to electric power in manufacturing should not be forgotten. Between 1880 and 1930, for example, the production and distribution of mechanical power rapidly evolved from water and steam prime movers with shaft and belt drive systems to electric motors that drove individual machines. (More on the impact of the individual motor later.)

With electrification, the energy required to drive machinery was greatly reduced, and industry obtained greater output per unit of capital and labor input. "Reduced energy needs and increased productivity in manufacturing influenced the relationship between energy consumption and gross national product in the first three decades of the twentieth century".

 

I feel extremely fortunate in locating two photos that depict vividly an important component in woodworking history, and especially given that the differences in scale are so remarkable.

(The 1887 photo on the left shows a scene in the classroom for woodworking course at the St Louis (Missouri) Manual Training School (Established 1879).  The photo on the right demonstrates how a home workshop can be set-up in 1930, with a Delta line of power tools, all driven by a fractional horsepower motor, thanks to the widespread availability of electric power for domestic use in the 1920s.)

Drive power is the issue. Today, we take for granted that a single electric motor drives each tool. Such an achievement betrays the long struggle woodworking -- along with other similar industries -- had to contend with (--- more later -- written 2-21-07)

In the late 1880's and early 1890's, far-reaching developments were under way, such as the use of electricity for street light­ing and operating streetcars. This was the beginning of our present method of power distribution and has affected life in general,' and machine design in particular, more than any pre­vious factor. By 1906, direct-current motors running 720-900 or 1000 rpm were being used coupled direct to machine countershafts.; A machine thus driven individually could be located in the most desirable position in regard to work flow, as it no longer was necessary to place it in relation to lineshafting which was often inconvenient and clumsy. Source: Judson H. Mansfield, "Woodworking Machinery: History of Development from 1852—1952", Mechanical Engineering: The Journal of the American Society of Mechanical Engineers, December 1952, pages 983-995. [some background info: Mansfield was Chief Engineer, Greenlees Brothers & Co., Rockford, IL, and the paper was ontributed by the Wood Industries Division and presented at the Fall Meeting, Chicago, Ill., September 8-11, 1952, of the ASME.

Sources: Calvin Milton Woodward, The manual training school, comprising a full statement of its aims, methods, and results, with figured drawings of shop exercises in woods and metals. Boston, D. C. Heath & co., 1887, page 26; Herbert E. Tautz and  Clyde J. Fruits, The modern motor-driven woodworking shop; how to plan, operate and get the most out of it, Milwaukee, Wis., Woodworkers educational department (Division of Delta manufacturing co.), 1930, page 38; Judson H. Mansfield, "Woodworking Machinery: History of Development from 1852—1952", Mechanical Engineering: The Journal of the American Society of Mechanical Engineers, December 1952, pages 983-995; Warren D. Devine, Jr., "From Shafts to Wires: Historical Perspective on Electrification," Journal of Economic History 43 (1983): 347-372 [This is the article that started my quest for background on the impact of the lineshaft drive systems.];Jesse H. Ausubel and Cesare Marchetti, "Elektron: Electrical Systems in Retrospect and Prospect" Daedalus 125(3):139-169 (Summer 1996)

Link Belt

This example of a Link Belt, [image needed] comes from the Woodcraft website

Left-Tilting Blade

See Right-Tilting Blade.

Leisure

Sources:

Linenfold

[good account and diagrams in blackburn 1997]

Lock-Miter Joint

Profile common in Shaper Cutters and Router Bits.

Loose Tenon

[temp -- cross ref will take readers to Mortise and Tenon eventually] both parts of the workpieces to be joined are Mortised with a separate tenon to hold them together. Differs from a traditional mortise and tenon which has the tenon as an integral part of the end grain part of the Mortise and Tenon joint. See Floating Tenon.

Lumber Grading

Grades of Lumber Grading of lumber is not an exact science, since it is done by looking over the lumber and deciding to which grade it belongs. However, this inspection is done by men highly trained in judging lumber. Standards may vary somewhat in different sections of the country. American Lumber Standards for grading lumber have been set up by the lumbering industries, the contractors, and the Bureau of Standards of the United States Government. These standards are usually followed in the grading of lumber. Lumber contains knots, pitch pockets, and other defects in varying amounts. The number and size of these defects determine the usefulness of the lumber for many purposes. The American Lumber Standards set up three groups of lumber according to its principal uses: yard lumber, structural timber, and factory or shop lumber. Yard lumber is that which is used for general building purposes; it is graded into two general classifications, select and common. There are four different grades of select lumber—A, B, C, and D. Grades A and B are suitable for natural finishing, while grades C and D are for painted surfaces. Common lumber has five different grades-1, 2, 3, 4, and 5. Numbers 1 and 2, common grades, are suitable for use with-out any waste. Numbers 3, 4, and 5 are low grades of lumber with many knots, blemishes, and knotholes. Structural timbers, those 5" or over in thickness and width, are graded according to the strength and use of the entire piece. Factory or shop lumber is intended for use in making articles where such defects as knots and knotholes may be removed in the manufacturing process. This lumber is graded on a basis of the proportion of us-able area for cutting a number of pieces of specified minimum size and quality. Sources: William H Johnson and Louis V. Newkirk. General Woodworking. New York: Macmillan, 1946, pages 6-7; Walter E Durbahn, "What You Should Know About Lumber", American Magazine 157 April 1954, page 67.