NIST's Million Pounds-Force* Deadweight Machine – the largest in the world – calibrates sensors that measure extremely large forces, such as the thrust of a rocket or jet engine. Beginning in late 2014, this unique instrument underwent a restoration that required disassembling the three-story weight stack for the first time in fifty years.
The process of cleaning, refurbishing, recalibrating, and reassembling the 50,000-lb masses took almost a year and a half and involved massive air hammers, 30-ton cranes, screws the size of your head, and a balance so large that it was built into the ground.
Here are the videos, photographs, news stories, and other resources produced by NIST’s Physical Measurement Laboratory to document this noteworthy event.
*One million pounds-force is equivalent to 4.45 million newtons of force
A Million Pounds in Action (Video)
This video shows NIST staff performing an actual calibration with the machine. Most clips sped up so that movement is visible.
Million-Pound Makeover Featurette (Video)
Project leader Rick Seifarth discusses the 16-month overhaul of NIST’s Million Pounds-Force Deadweight Machine. The featurette includes video of the demolition of the instrument's three-story weight stack; machine shop repairs of minor damage from 50 years of use; recalibration of the 50,000-pound stainless steel weights in the stack; and the final reassembly of the system with its refurbished weights.
News story: "Million-Pound Deadweight Machine Officially Open for Business," June 2, 2016
Million-Pound Makeover: Anatomy of the Deadweight Machine (Video)
This animation explores the anatomy of the device, from its three-story stack of stainless steel discs to the hydraulic equipment that lifts and lowers the million pounds of steel, and walks the viewer through a sample calibration of a customer's force sensor.
Million-Pound Makeover: Disassembling the Weight Stack (Video)
Dismantling the deadweight machine prior to restoration took several weeks, since each piece had to be unbolted and carefully lifted with cranes. This video reel contains highlights from the disassembly process.
News story: "Restoration Begins on NIST's Million-Pound Deadweight Machine," published January 27, 2015
Million-Pound Makeover: Calibrating the Weight Stack (Video)
Before the weight stack could be reassembled, it had be carefully calibrated to ensure that the machine
applies precisely the right amount of force. This video explains how the calibration was done, beginning with a standard kilogram mass – equivalent to a little bit more than 2 pounds – and working up to the machine’s 50,000-lb masses through a series of comparisons.
"NIST's Million-Pound Weight Stack Restoration is Complete"
News story, published April 25, 2016
"Progress Report with Photos: Restoration of NIST's Million-Pound Deadweight Machine"
News story, published June 30, 2015
Reconditioning of the 4.45 MN deadweight machine
A technical description of the restoration process