Evening Republican, Volume 21, Number 305, Rensselaer, Jasper County, 31 December 1917 — Grinding Wheels Must Do The Very Finest of Work. [ARTICLE]

Grinding Wheels Must Do The Very Finest of Work.

Grinding wheels have fine work to do, writes Ellwood Hendrick in the Scientific American. Limits of irregularity as low as 0.0005 inches and 0.00024Jnches are often given. And it shoula be remembered that when 0.00025 of an inch is being ground, the heavy slide that carries the wheel and wheel spindles moves forward only half that distance. If a piece of tissue paper were split twelve times consecutively, it would have the thickness under which these machines have constantly to work. And yet, when we consider the forces present in a wheel weighing 200. pounds rotating at a speed of 1,200 revolutions per minute, we are not reminded of a watchmaker’s lathe, despite the exquisite precision of the operation.