Find number abcIf bb8a1 + 4b9bc = ac78a find number abc. Multiple solutions may exist.
Correct answers: 13
The first user who solved this task is Nílton Corrêa de Sousa.
Universal milling machineIn 1865, a U.S. patent was issued for the universal milling machine invented by Joseph Rogers Brown (No. 46,521). With this four-speed, 1,800-lb machine, Brown could quickly make any size twist drill, and replace previously tedious handwork in spiral milling or gear-cutting operations. Adjustments were calibrated with an accuracy of one-thousandth of an inch. He had already invented a precision gear cutter in 1855 to produce clock gears, and later patented a universal grinding machine in 1877. As an inventor, Brown made numerous advances in the field of fine measurement and machine-tool production. He co-founded J.R. Brown and Sharpe in 1853 to manufacture his products.