In Robert V. Jacobs’ biography, Lewis R. Heim, Mechanical Genius of Modern Industry, Jacobs describes Heim as “a mechanical genius and industrial entrepreneur whose many inventions helped usher in the modern American industrial age.”¹ Jacobs goes on to say that Heim’s Centerless Cylindrical Grinder “allowed for mass production of machinery and automobiles.”
Heim was the founder of the Ball and Roller Bearing Company in Danbury, CT. Heim needed to manufacture his roller-bearing rolls to within a quarter-thousandth of an inch tolerance (0.00025″). Unfortunately, that wasn’t always possible with the available technology – so really he was only able to achieve .0005″ tolerance. This difference proved to reduce the durability and lifespan of the bearings.
Particular improvements that increased precision & tightened tolerances included swapping a powered regulating wheel instead of a stationary pressure block provided, and a work rest that directed forces so that the workpiece could tend to approach roundness while it was being finished.² Heim’s patent for a Double-Ring Wheel Centerless Grinder was issued in 1915, and the Heim Centerless Grinder was acquired by Cincinnati Milling Machine (later Cincincinnati Milacron) in 1922.
From an advertisement, Feb 1921: “For speedy, accurate grinding of cylindrical parts, there’s nothing to beat the Heim Centerless Grinder. With this machine, production can be increased from 50% to 500%. It is automatic in operation — assures maximum economy in the handling of such work as rolls for roller bearings, wrist pins, cam shafts, valve lifters, valve lifter roll pins, pistons, shackle bolts, spring bolts, roller chain studs; any cylindrical part, in brief, with but one diameter to be ground. A large battery of these machines in our plant grinds rolls for journal roller bearings, radial roller bearing, and various small cylindrical parts.”
Here’s the profile of Lewis Heim on The Manufacturing Ledger, and here’s the Centerless Grinder!
Want more content from the American Precision Museum?
Sign up to receive news straight to your inbox!