Many years ago, when asked how the
five-meter gear was checked, the quality manager responded, “When they’re that big, they’re never bad!” That may have been the attitude and practice in the past, but it no longer serves the manufacturer nor the customer. Requirements have been evolving steadily, requiring gears to
perform better and last longer.
Here is some history that bears repeating - or at least re-reading. So take a few minutes to give it up for a long-gone Brit named Henry Maudslay
(August 22, 1771 - February 14, 1831) - also known as "A Founding Father of Machine Tool Technology." You might
also consider him an early leader in inspection, as he also invented the first bench micrometer capable of measuring to one ten-thousandth of an inch.
At the dawn of the Industrial
Revolution, so-called mechanics
were tasked with devising the precise methods that would make mass production possible. The result was the first generation of machine tools, which in turn required improved tooling and production methods.
Gears with a diametral pitch 20 and
greater, or a module 1.25 millimeters
and lower, are called fine-pitch or low-module gears. The design of these gears has its own specifics.