James N. Heald (1846-1931)
After graduating from Worcester Polytechnic, Heald became a partner with his father in the blacksmith shop, foundry, and machine shop his family had operated for 60 years in Heald Village near Barre, Massachusetts. In 1903, James Heald obtained financing to buy the firm from his father and moved it to Worcester. He had already developed a lathe attachment for both internal and external grinding and a successful drill point grinder. In 190S, Heald introduced a rotary grinder for the sides of piston rings. This brought him in contact with the problems encountered with cylinders for auto engines. Up to that time, boring, reaming, and lapping were the usual methods. Grinding was ruled out because of the difficulty of rotating the engine block around the cylinder centerline. The thin walls would spring away from the boring tool, causing an uneven surface. In 1905, Heald devised a grinding machine with a planetary action that was so well designed that such machines differ little even today. Heald’s grinding machine quickly became the standard production method for both auto and aircraft engines. Later Heald added automatic size control, and developed hydraulic table feed and centerless internal grinders.