1- The Micrometer - History
In the 18th century the industrial revolution was in full swing. New industrial and agricultural machines were invented and patented every year.

One thing that hindered precision manufacture of these machines was a accurate method of measurement. In 1772 James Watt - who also invented the steam engine - invented a screw device that moved a pair of jaws in and out (image on the right). When a part made contact with those jaws two disk-like dials would show the measurement.

The Frenchman, Jean Palmer in 1848 designed and patented the the portable one-handed micrometer now used throughout the world (right). Brown and Sharpe, American manufacturers of clocks, watches, jewelry, and silverware, saw this device at the Parisian Exposition in 1867. Ten years later, they obtained the patent rights from Palmer to produce the tool.

Patents for the micrometer have long run out and now many manufactures worldwide are producing the device in a wide range of prices. It is possible to place the least expensive with a costly mike side by side and it would be difficult to visually tell them apart. More than likely the least expensive micrometer will measure accuracy within .001 and better. For the casual user this may be adequate, for the professional the instrument must have reliability and longevity.