Torque Tools History
Beam, click and digital torque wrenches and why controlled fastening mattered.
Who invented the torque wrench?
Short answer: Conrad Bahr, who worked for the New York City water department, is generally credited with patenting an early torque-limiting wrench in 1918.
Conrad Bahr, who worked for the New York City water department, is generally credited with patenting an early torque-limiting wrench in 1918. The tool helped prevent overtightening of bolts on water mains and steam pipes, and torque wrenches later became essential in automotive repair.
Why were beam-type torque wrenches common in twentieth-century shops?
Short answer: Beam-type torque wrenches use a flexing beam and a pointer on a scale.
Beam-type torque wrenches use a flexing beam and a pointer on a scale. Their simple design has no internal mechanism to wear, which made them a common torque tool in automotive shops for much of the twentieth century.
Who is associated with the deflecting beam torque wrench?
Short answer: Paul Allen Sturtevant is credited with patenting a deflecting beam torque wrench in the 1930s.
Paul Allen Sturtevant is credited with patenting a deflecting beam torque wrench in the 1930s. The company associated with him, Sturtevant Richmont, became a long-running maker of torque tools.
How did the click-type torque wrench become the most common professional design?
Short answer: Click-type torque wrenches use a spring-loaded mechanism that clicks at a preset torque.
Click-type torque wrenches use a spring-loaded mechanism that clicks at a preset torque. They became the most common professional design in the second half of the twentieth century because they are easy to use and give a clear signal.
When did digital torque wrenches become popular?
Short answer: Digital torque wrenches, which use electronic sensors to measure torque and often angle, became popular in the late twentieth and early twenty-first centuries.
Digital torque wrenches, which use electronic sensors to measure torque and often angle, became popular in the late twentieth and early twenty-first centuries. They suited torque-to-yield fasteners and quality control, and some store readings for documentation.
Why did torque specifications become important in auto repair?
Short answer: As engines adopted lighter materials such as aluminum and tighter tolerances, manufacturers specified torque values to achieve proper clamping force without damaging parts.
As engines adopted lighter materials such as aluminum and tighter tolerances, manufacturers specified torque values to achieve proper clamping force without damaging parts. Following torque specs became standard practice to prevent leaks, warping and fastener failure.
When did torque-angle tightening become common?
Short answer: Torque-angle tightening became common in the late twentieth century as automakers adopted torque-to-yield head bolts.
Torque-angle tightening became common in the late twentieth century as automakers adopted torque-to-yield head bolts. It involves tightening to an initial torque and then turning a set number of degrees for more consistent clamping force.
Why did torque multipliers come into use for heavy fasteners?
Short answer: Torque multipliers use internal gearing to multiply input torque, letting a technician reach very high values with a standard torque wrench.
Torque multipliers use internal gearing to multiply input torque, letting a technician reach very high values with a standard torque wrench. They came into use for heavy truck, equipment and industrial fasteners where the required torque exceeded what a person could safely apply with a long handle.
Why did inch-pound torque wrenches become more important?
Short answer: Small fasteners in valve covers, intake components and sensors require low torque values.
Small fasteners in valve covers, intake components and sensors require low torque values. Inch-pound torque wrenches became more important as vehicles used more aluminum, plastic and composite parts.
Why did lug nut torque become a focus in tire shops?
Short answer: Overtightened or unevenly tightened lug nuts can warp brake rotors or damage studs, while undertightened nuts can loosen.
Overtightened or unevenly tightened lug nuts can warp brake rotors or damage studs, while undertightened nuts can loosen. Tire shops increasingly emphasized proper torque procedures to improve safety and reduce comebacks.
Why did torque screwdrivers become important for small fasteners?
Short answer: As vehicles added electronics, sensors and small fasteners threaded into plastic or aluminum, low torque values became critical.
As vehicles added electronics, sensors and small fasteners threaded into plastic or aluminum, low torque values became critical. Torque screwdrivers, long used in electronics and aviation work, became useful in auto shops for these delicate fasteners.
How did the split-beam torque wrench design differ from earlier click wrenches?
Short answer: Split-beam torque wrenches use a secondary beam to set torque instead of compressing the main spring, so they do not need to be returned to the lowest setting after use.
Split-beam torque wrenches use a secondary beam to set torque instead of compressing the main spring, so they do not need to be returned to the lowest setting after use. The design arrived later than the classic click wrench as an alternative to traditional coil-spring click wrenches.
What were early torque wrenches used for in auto shops?
Short answer: Early torque wrenches in auto shops were often used for cylinder heads, connecting rods and main bearing caps, where consistent clamping force is critical.
Early torque wrenches in auto shops were often used for cylinder heads, connecting rods and main bearing caps, where consistent clamping force is critical. Over time, torque specifications expanded to many other components.
Where did hydraulic torque wrenches come from?
Short answer: Hydraulic torque wrenches use a hydraulic cylinder to apply very high, controlled torque.
Hydraulic torque wrenches use a hydraulic cylinder to apply very high, controlled torque. They developed for industrial bolting such as pipelines, power plants and heavy equipment, and later found use on large truck and mining equipment fasteners.
Why did torque wrench accuracy standards develop?
Short answer: As industries such as aviation and automotive manufacturing relied on torque specifications, they needed consistent tool accuracy.
As industries such as aviation and automotive manufacturing relied on torque specifications, they needed consistent tool accuracy. Standards such as ASME B107 and ISO 6789 developed to define performance and calibration requirements.
General guidance only. Follow the vehicle and tool manufacturer's procedures, and confirm vehicle coverage on the tool maker's list before buying.