wrench
n.— «Adams already had experience fixing bicycles because he did it so much on his own. Soon after completing the bicycle school, DNS closed the lab where Adams was stationed. He decided to became a bike mechanic or—as they call them in the bicycle industry—a “wrench” at a bike shop in Berkeley, Calif.» —“Entrepreneur loves being a ’wrench'” by Caleb Sheaffer Citizens Voice (Wilkes-Barre, Pennsylvania) Mar. 9, 2008. (source: Double-Tongued Dictionary)