5.
Technological
development: e.g., availability of alternating current; portability of
power machines:
In 1907, eight percent of America’s households were wired for
electricity; by 1920, 35 percent were wired; by the beginning of World
War II, 80 percent were wired.
Sources: Harry Jerome,
“Mechanization in Industry”, New York: National Bureau of Economic Research,
1934, pages 174-175; Warren Devine, “From Shafts to Wires: Historical
Perspective on Electrification”, The Journal of Economic History,
43, No. 2 (June 1983), pages347-372.
The three boxed-texts
below come from the recollections of the mechanical engineer, Judson
Mansfield.
DIRECT-CURRENT ELECTRIC MOTORS IN 1906
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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, page 992.
Electric Motor Drives
In 1906 the Oliver Machinery company was the first in the United States to adopt the direct built-in type of electric motor-driven woodworking machine.
This consisted of a motor head wood turning speed lathe where -- in the motor shaft and the headstock spindle were one and the same -- and the motor took the place of the headstock of the lathe.
About 1912, the first high speed 3,600 R.P.M. alternating-current induction motor was invented, meaning significant progress in modernizing the design and use of woodworking machinery.
With a speed of 3,600 R.P.M. the electric motor soon began to be coupled attached directly to the shafts on the ends of cutter heads on surface planers, jointers, etc.
The impact: eliminate all intermediate, non-essential parts, which, for years were necessary to deliver power to the cutting unit.
[But, still, for the most part, the motor was separate as was the cutting arbor unit -they were merely coupled together.]
Source: A. P. Johnson and Marta K. Sironen, Manual of the Furniture Arts and Crafts Grand Rapids, Mich.: A.P. Johnson Co., 1928.
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For a photo of what looks like power
tools powered by DC motors in a
homeshop in 1910,
checkout Document 42
BALL
BEARINGS BECOME AVAILABLE IN 1908
In
a stocktaking of the progress in woodworking machines, between 1852 and
1952, the mechanical engineer, Judson Mansfield, notes that
Another
development of [first decade of century 21] was our early
automobiles. Free-running high-capacity ball or roller
bearings, occupying small space and mounted in light
dirt-proof housings, were necessary for the
successful operation of autos.
These early trouble-free and hardened-steel sealed bearings were
brought to the attention of wood-shop operators, resulting in their
trial for woodworking machinery. Long bearing life, less
frequent
lubrication, cleanliness, and case of replacement were a few of the
advantages which brought about their rapid acceptance.
Shorter, stiffer spindles and bearing housings, occupying less space,
were all made possible by the use of ball bearings.
Ball-bearing
arbors were first furnished as a desirable feature on jointers, to
special order, as early as 1908. By 1923 they were available
as
standard equipment on most woodworking machines.
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, page 992.
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THIN
HIGH-SPEED CUTTER KNIVES IN 1909
In 1909 thin high-speed knives mounted in
circular cylinders, for jointers, surfacers, and molders began to
appear. The safety of these, when used in jointers, was aggressively
advertised and their use has saved many fingers and hands. The thin
knives were locked in the cylinders by various de-signs of gibe and
clamp screws, eliminating the danger of the broken knife bolts which
were required with the thick knives previously used on the old
square-type heads.
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, page 992.
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Early Portable Routers: Kelley Electric Machine Co. of Buffalo, 1900s click here for link to some background on router history
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