HISTORY
OF MILLING
Where
does the term milling come from? The term milling can be traced back to the
Latin root Miola, or grindstone.
Early
face milling cutters resembled flour-milling grindstones of the beginning of the
nineteenth century. They were circular type of stone that was used to crush
wheat.
In 1818 the first milling machine was made. It was thought
that Eli Whitney invented the milling machine, but it was Simeon North or one of
his sons. It had a head from a lathe and a wood cone pulley for a belt drive.
Between 1819 and 1826 an
important development took place at Harper’s Ferry Armory VA. John Hall
developed a series of precision machines. There were three types of machines;
they were called Cutting Engines for straight cutting, curved cutting, and lever
cutting.
The machine known as the
straight-cutting machine became the plain miller. The curve-cutting machine
became the profile-milling machine that had a rise and fall of the table in
response to a pattern plate below the table. The lever-cutting machine is
similar to the hand miller.
Visitors and workers in Harper’s Ferry carried the
technology to New England, where North Ordnance had an arms factory.
In 1828 a contract for 5000 Hall rifles was awarded to North from the
Ordnance Dept, these rifles were to have parts that were interchangeable with
the rifles made in Virginia.
A
fair amount of successes in making interchangeable rifle parts had been achieved
by gun manufacture Robbins & Lawrence from Vermont.
There was an exhibition in London’s Crystal Palace, where Robbins &
Lawrence showed off these machines. After the show the firm began shipping over
150 machines to England’s Enfield Arms Works, of these 75 were milling
machines.
There was a serious
drawback to the early miller’s, they had no way to adjusted vertically, most
designers thought of them as a lathe.
Shortly
after Frederick Howe arrived at Robbins & Lawrence after serving his
apprenticeship at Gay, Silver & Co. He had built a plain milling machine, so
far as the vertical feed was concerned, this machine was a backward step, but in
all other respects it was a major step ahead. At least for the kind of work that
was done by most armories. Howe improved on this machine, and in 1850 he
developed the index-milling machine. The work could be positioned in rotation in
the horizontal plane and adjusted vertically by a lead screw. In 1852, Howe
improved the rigidity of the mill. The design was sold to the British for
Enfield.
It
is thought that Francis Pratt modified this machine into the famous Lincoln
Miller. The Lincoln miller was a manufacturing machine, it was an excellent
machine for performing the same operation over and over, but it totally lacked
the kind of flexibility in the tool room that the engine lathe was able to
provide for turning operations.
It wasn’t until 1862
that the knee & column mill was developed, it was Joseph R Brown’s idea
for a universal milling machine that was a true tool room mill. This brought the
milling machine from the crude design of Simon North to a machine of universal
industrial caliber.
The
process of milling, which includes machines, cutters, is one of the most
important metalworking processes. It is the most versatile, with it’s ability
to carve large workpieces, or do work on miniature ones. It is the most
efficient means of reducing a raw workpiece to a finish shape.
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