The kinks and other information given in this book have been
from the experience of thoroughly practical men, as originally
published in the American Machinist.
This volume forms one of a series of this nature, aiming always
to make available out-of-the-way information when most wanted.
In this form the Kink Books, which can be kept in the tool-chest
or the pocket, and always referred to, will, we feel, meet a
demand and serve a good purpose.
F. H. Colvin and F. A. Stanley
New York, November, 1907.
has not often seen a machinist pick up a bar of metal covered
with rust and dirt and wonder whether it was tool steel or
machine steel. Now, there are a number of means of finding this
out, but the emery wheel test, while not a particularly refined
method (it will not tell you everything about a steel) is as
quick and handy as any.
To test a piece, touch it lightly against a dry
emery wheel and observe the sparks as they strike the frame of
the machine. A high-carbon steel gives a spark which apparently
bursts into a brilliant star-like point of light when it strikes
The spark from a low-carbon steel is, on the
contrary, merely a dull, incandescent particle. It is said that
all the air-hardening steels give a very red spark.
By the way, some air-hardening steels can be
greatly improved by heating to a bright red and quenching in
oil. In grinding after this care should be taken not to start