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Samuel Calvin McLanahan​
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Samuel Calvin McLanahan, through his inventive genius, changed the direction of his family’s company from that of a foundry to a leading manufacturer of minerals processing equipment. His most important inventions—the Log Washer and the Single Roll Crusher—remain in use worldwide in a wide range of minerals processing plants.​

S. C. McLanahan was born in Hollidaysburg, Pennsylvania, the son of James Craig McLanahan, one of the original founders of what is now McLanahan Corporation. A child genius, he developed the first accounting system for the company at the age of 14. At the age of 18, he ran the Car Wheel Boring Mill and Wheel Press, a job that had required two men. At 21, during the Civil War, he entered the U.S. Navy and distinguished himself during the blockade of several Confederate seaports. He ended his naval service after six years.​

In the summer of 1875, S. C. McLanahan built a battery of red ore coke ovens for the Vinton Furnace in Ohio. Next, he purchased a one-sixth interest in the family business—at that time a foundry and machine shop. In the early days, he produced all the drawings, estimates, contracts, and correspondence for the business. He also designed and built four 72” x 36” x 6’ stroke blowing engines, each weighing approximately 100 tons. One of these, at Rockdale, Tennessee remained in continuous operation until 1947.​

Around 1890, S. C. conceived a way to wash clay from the rock in his family’s phosphate deposits in Florida. Inside a long wooden box, he mounted wooden logs and attached cast iron paddles to them. On January 27, 1891, he secured a patent for his new machine and called it the Log Washer. This invention changed forever the direction of McLanahan Corporation. Next, he realized the need for a simple primary crusher that could handle wet, sticky feed containing pieces too large for the Log Washer. In 1894, he invented the Single Roll Crusher to deal with this problem.​

The Log Washer quickly became a favorite for processing iron, manganese, and phosphate ores, and by 1913, more than 500 Single Roll Crushers had been built to process coal, lignite, shale, and limestone. Log Washers and Single Roll Crushers remain standard pieces of processing equipment in use around the world. Together, they launched McLanahan Corporation into building a wide range of process equipment and systems. As of 2010, the company was in its 175th year of business and sixth generation of family ownership.​

S. C. McLanahan went on to design (or improve the design) of many types of process equipment, including retort coke ovens, furnaces, rolling mills, blowing engines, ore jigs, screens, elevators, conveyors, dryers, steam engines, and many more. He was active in the company until his death on May 20, 1928. He laid the groundwork for McLanahan Corporation as it exists today. He was a genius inventor, entrepreneur, and ultimate family man. Many types of equipment used today in the process industries around the world can be traced to the original ideas of Samuel Calvin McLanahan.​