An American renaissance in manufacturing is needed—and long overdue.

This article provides an overview of the benefits of using psychoacoustic characteristics for describing gear noise. And with that, human hearing and the most important psychoacoustic values are introduced. Finally, results of noise tests with different gear sets aree presented. The tests are the basis for a correlation analysis between psychoacoustic values and gear characteristics.

If anyone should ever need convincing that the state of American manufacturing is in ongoing decline, consider this: the state of Michigan has the highest concentration of engineers in the country, yet also has the highest unemployment rate. But there are ripples of hope out there as grassroots and otherwise organized groups are fighting the good fight in an attempt to reverse that trend.

Matt McBride of Riverside Spline & Gear responds to last issue's Voices piece by Fred Young, and Tom Schmitt of Schmitt Design responds to last issue's publisher's page.

Lamentations continue—legitimately so—over the second-citizen status of manufacturing in the United States. The need undoubtedly continues for renewed support by government and educators for making things here once again...

Lack of skilled workers mirrors U.S. manufacturing's decline.

Increased productivity in roughing operations for gear cutting depends mainly on lower production costs in the hobbing process. In addition, certain gears can be manufactured by shaping, which also needs to be taken into account in the search for a more cost-effective form of production.

No one is quite sure when gears were invented. It's universally agreed, however, that they've been transmitting motion in one form or another for quite a long time.