Torque wrench
（重定向自Torque spanner）
![](/Images/godic/202502/17/Torque_wrench_reading_view_06885611.jpg")
![Click-type torque wrench with socket attached, adjusted by turning the knurled handle.Click-type torque wrench with an open end and preset torque.](/Images/godic/202502/17/Click-torque-wrench5611.jpg")
A torque wrench is a tool used to precisely apply a specific torque to a fastener such as a nut or bolt. It is usually in the form of a socket wrench with special internal mechanisms. It was invented by Conrad Bahr in 1918 while working for the New York City Water Department. It was designed to prevent overtightening bolts on water main and steam pipe repairs underground.