Blog Post

World's Largest Deadweight Machine, world record in Gaithersburg, Maryland

January 31, 2024

Gaithersburg, Maryland, United States--The National Institute of Standards and Technology (NIST) deadweight machine in Gaithersburg, Maryland, United States, is a three-story, million-pound stack of steel disks used to calibrate devices called load cells that are used for measuring large forces, such as a rocket’s thrust or an airplane wing’s deflection; it sets the world record for being the World's Largest Deadweight Machine, according to the WORLD RECORD ACADEMY.

"NIST's Million Pound Deadweight Machine is used to calibrate sensors that measure enormous forces, like those created by the thrust of a rocket or jet engine," the National Institute of Standards and Technology (NIST) says.

"After going through a major restoration last year, this unique machine – it’s the largest in the world – is back online and calibrating sensors for NASA, aerospace companies, and more."

"It costs around $10,000 per pound to lift an object into space. With that kind of price tag, it’s important everything works on the first attempt. For any rocket launch to be a success, the force generated by the rocket has to be known and controllable, but with rockets routinely generating force measured in the Meganewtons, obtaining an accurate measurement is a herculean challenge.

"Enter the National Institute of Standards and Technology (NIST) deadweight machine, a three-story, million-pound stack of steel disks that helps calibrate the technology that makes this later achievement possible. It’s the largest machine of its kind in the world," the Atlas Obscura says.

"The NIST deadweight machine is used to calibrate devices called load cells that are used for measuring large forces, such as a rocket’s thrust or an airplane wing’s deflection. This astounding accuracy is a result of the process of comparison that yields each 50,000-pound weight. It starts with the official American kilogram (also housed at NIST). Then, larger weights are compared using incredibly precise balances."

"The last few bolts were tightened just weeks ago – by hand. Now fully restored, NIST's 4.45 meganewton (one million pounds-force) deadweight machine – the largest in the world – is back online and once again performing force calibrations for customers, which include U.S. aerospace manufacturers, U.S. military laboratories, and top-end commercial force calibration labs," the National Institute of Standards and Technology (NIST) says.

"NIST's million pounds-force deadweight machine is designed to produce forces of up to 4.45 million newtons (equivalent to one million pounds-force) to calibrate force-measuring devices called load cells. Those calibrated load cells are then used by customers to measure large forces – for example, the thrust of a rocket or jet engine or the deflection of an airplane wing.

"Forces are generated in the machine by hanging the stainless steel weights from the load cell being tested. The weight stack consists of a calibrated lifting frame and 19 nearly identical stainless steel discs about three meters in diameter (a little less than ten feet) when assembled, with an average mass of about 22,696 kg (just over 50,000 pounds) each."

"The National Institute of Standards and Technology (NIST) has brought the world’s largest deadweight machine back online, after more than a year of maintenance. This marks the first time the machine has ever been recalibrated since its construction in 1965," the Engineering.com says.

"That might sound like a long time to go without any recalibration, but it makes sense when you realize that the machine’s total height is roughly ten stories. This includes the laboratory/control room and the large hydraulic ram above it which lifts the three-story weight stack.

"The machine is designed to generate forces of up to 4.45 million newtons (equivalent to one million pounds-force) for the calibration of load cells. Quality professionals then use the calibrated cells to measure large forces, such as rocket or jet engine thrust or the deflection of airplane wings."

"Building just about anything, it turns out — from skyscrapers to medical devices to airplanes — requires an understanding of how materials respond to force, he says, and this NIST lab is dedicated to the precise measurement of force. The NIST's machine uses a million pounds of dead weight — the stainless steel — to generate a million pounds of force," the NPR says.

"The control room for the machine looks just like it did when this place was built five decades ago — with old-fashioned green consoles that have knobs and switches. Seifarth fiddles with them, and the red hand of a dial starts to move. The numbers on the dial go up to a million.

"The weights are disks that look to be about 10 feet across, and they're arranged in a stack. They are linked together, sort of like a chain. So when the machine picks them up, they just hang straight down, in midair."

"In 1965 NIST in Gaithersburg, Maryland, built a machine that uses a stack of stainless steel plates to apply up to 1 million pounds (4.4 million N) of force to test materials' physical properties," the American Institute of Physics says.

"It was then, and still is, the largest machine of its kind in the world. Over the past year-and-a-half, the machine underwent refurbishment for the first time. The weights, which accumulated damage over the years, were repaired, and the entire machine was taken apart and then put back together and recalibrated.

"Earlier this month the machine returned to operation and is working through a backlog of measurement requests."

"It’s official, NIST’s 4.45-million newton (equivalent to one million pounds-force) deadweight machine – the largest in the world – is back in one piece after a colossal 16-month effort to overhaul the system for the first time in 50 years," the Industrial Equipment News says.

"The year-and-a-half-long saga involved dismantling, cleaning, restoring, and recalibrating about half of the stainless steel discs in the three-story stack of weights. It marked the first time the device had been taken apart since its original installation in 1965.

"The deadweight system consists of a calibrated “T-shaped” lifting frame and a stack of 19 stainless steel discs about three meters in diameter (a little less than ten feet) when assembled. Their average mass is about 22,696 kg (just over 50,000 pounds) each."