Inventor Jim Lewis explains: "The idea evolved from exploring ways to balance a high-performance spinning top. I realized I could put a fairly sophisticated mathematical algorithm on a Web page to help people balance anything from flywheels to automobile wheels.

"The Web page gives an easy-to-follow method for dynamically balancing any rotating mass without expensive tools. Users just need a way to affix counterweights to the wheel," says Lewis, president of eMachineShop, Midland Park, N.J.

The technique involves putting small counterweights on the device being balanced, spinning it, and making observations. The user then enters their visual or audible observations into the online tool, which recommends where the next set of weights should go.

It is hoped that the tool, available at www.emachineshop.comby clicking on the Toolbox link, will be popular with engineers, inventors, auto buffs, and mechanics.