Sir Joseph Whitworth, 1st Baronet was an English engineer, entrepreneur, inventor and philanthropist. In 1841, he devised the British Standard Whitworth system, which created an accepted standard for screw threads. Whitworth also created the Whitworth rifle, often called the "sharpshooter" because of its accuracy, which is considered one of the earliest examples of a sniper rifle, used by some Confederate forces during the American Civil war.
By unknown artist, Whitworth c. 1846
The Firs, now the Chancellors Hotel & Conference Centre
The grave of Sir Joseph Whitworth Bart. In the grounds of St Helen's Parish Church, Darley Dale, Derbyshire (Whitworth's grave is the central tomb)
12-pounder Whitworth rifle
A screw thread is a helical structure used to convert between rotational and linear movement or force. A screw thread is a ridge wrapped around a cylinder or cone in the form of a helix, with the former being called a straight thread and the latter called a tapered thread. A screw thread is the essential feature of the screw as a simple machine and also as a threaded fastener.
Screw thread, used to convert torque into the linear force in the flood gate. The operator rotates the small vertical bevel gear in the center. Through mechanical advantage this causes the horizontal bevel gears (at far left and far right, with threaded center holes) to rotate. Their rotation raises or lowers the two long vertical threaded shafts - as they are not free to rotate.
Different (and incompatible) threads including (from left) M12 left hand, standard M12, M12x1.5 (fine), M12x1.25 (fine), 1/2" UNF, 1/2" UNC, 1/2" BSW, and 1/2" BSF
Camshaft cover stud threaded 1⁄4-20 UNC (left, for aluminium cylinder head) and 1⁄4-28 UNF (right, for steel nut; from a 1960s Jaguar XK engine)
The three diameters that characterize threads