[RoosterRedux]

Vikings knew the specified RPM of their drills without first reading the manual.

Did Vikings use drills in the exploration of the North Atlantic and North America?

Gee, ya learn new something everyday.;-)

[PeterPrinciple]

Vikings knew the specified RPM of their drills without first reading the manual.

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Just watched an ww11 movie. The engineers were trained to know the rpm of engines by sound and vibrations, no gauges.

The human being is the most marvelous creation...................