Google Glass pulled its smart eyeglasses from the consumer marketplace two years ago after privacy advocates screeched that the oh-so-cool computerized specs might be usurped by ne'er-do-wells to make secret YouTube videos.

Fast forward two years. Glass has been reborn as an emerging "lean" industrial tool inside AGCO's custom-tractor factory in Jackson, Minn. The technology cut costs so successfully, it will soon be rolled out to AGCO factories worldwide.

Here's why.

Instead of repeatedly scrambling between a tractor on the production line and an instructional monitor 15 feet away, AGCO assemblers now just don a pair of Google smart glasses and scan a tractor's serial number to get all instructions needed.

The scan — or just the click of a button on the side of the eyeglasses — immediately downloads the tractor manual, assembly instructions, checklists or photos onto the tiny eyeglass computer screen above the worker's right lens. The smart eyeglasses also use voice commands to free hands and so workers can leave voice notes or instructions for the next shift worker just by talking to the eyeglasses.

"It's neat stuff. With Glass, we have seen a significant increase in productivity, and our factory employees have reported being much happier doing their jobs," said Peggy Gulick, director of business process improvement for AGCO.

Since the giant tractor plant began experimenting with Glass technology three years ago, training, production and inspection times have dropped 25 to 70 percent. Right now, the factory has 850 workers but only 100 pairs of the smart glasses.

"We will have 500 to 1,000 pairs in the next 12 to 18 months" in AGCO facilities in Minnesota, Kansas, Illinois, Germany, Italy and Brazil, Gulick said.

AGCO is one of 50 corporate pioneers — which also include Boeing, Volkswagen, General Electric and DHL — that found commercial uses for Google's consumer glasses inside factories or warehouses. With the partners' input, Google reintroduced its defunct consumer Glass product last month. The new, lighter and commercial version is dubbed the Glass Enterprise Edition.

"AGCO was an early adopter of Glass in the workplace, and their business results highlight how useful it can be for manufacturing workers to have all the information they need to get the job done right in their line of sight," said Jay Kothari, the Glass Project lead at Google X.

Like Google, Microsoft, Sony, Epson and Daqri are also developing "augmented reality" eyeglasses that might help manufacturing customers design prototypes, produce goods more efficiently, and train workers faster. Market research firm Forrester predicts that by 2025, 14 million workers will regularly use such devices to perform their jobs.

"But right now, we are still very much in the early days of this [growing] technology," said Alex West, principal analyst of IHS Markit's smart manufacturing division. A recent IHS survey of 400 manufacturers found 20 percent were conducting trials or planning to use augmented reality devices next year.

Some early adopters, like Lockheed Martin, used smart glasses to let factory workers and third-party engineers communicate remotely to fix problems. Some glasses let workers Skype with product support centers. In some cases, the glasses overlap an employee's real product image with virtual instructive images that show where a particular part should go, West said.

"Lockheed Martin introduced augmented reality solutions from Epson while manufacturing their F-35 fighter planes. And they have introduced glasses that show engineers where they should be fitting different parts along with things like the parts numbers," West said. "They reckon there is a 30 percent productivity improvement for just helping engineers work more effectively."

AGCO saw similar results, Gulick said.

AGCO's journey with smart glasses started in late 2013, when an information technology worker in Minnesota received a pair of consumer smart glasses from Google.

From there, he and other employees spent 2014 dreaming of how the gee-whiz eyeglasses might be used inside AGCO.

The first solid idea solved a major problem, Gulick said.

AGCO's quality inspectors regularly used $3,000 computer tablets to perform quality checks on each custom-made tractor. But the tablets often dropped, broke or were run over. Perhaps smart eyeglasses could solve that.

To find out, AGCO bought 12 Google Glass sets from Google in 2014 for about $1,100 to $1,500 each.

The company asked its safety-equipment vendor, 3M Co., to retrofit the 12 smart glasses with safety glass so they complied with OSHA factory guidelines.

Next, Gulick, AGCO system analyst Dane Zittritsch and the rest of the team partnered with Belgium software firm Proceedix.

The software maker equipped the smart glasses with Wi-Fi accessible software so any AGCO worker could download tractor assembly instructions, checklists or process videos just by touching the eyeglass arm, talking or scanning a bar code.

AGCO, Proceedix and Google met regularly to fine tune the new industrial uses. AGCO made changes that extended the battery life. It made sure no applications required employees to be tethered to their workstations.

And they analyzed loads of data.

When ready, Gulick's team asked AGCO engine builder Heather Erickson to use the upgraded eyewear to do her job. With instructions for each custom tractor clearly in sight, Erickson started building each massive engine faster.

Soon AGCO equipped other workers with the glasses, took suggestions and made changes. AGCO added software and tested the devices in new parts of the factory.

Last year, tractor quality inspectors began using the glasses to pass or decline vehicle parts. A simple "OK Glass, proceed" command sent a tractor part to the next inspection station. The words, "OK Glass, decline," sent the tractor part back to production for a detailed analysis on what went wrong.

By March 2017, AGCO's Jackson plant had enough data to know it was onto something significant.

"We discovered that training with smart glasses is a grand slam," Gulick said. "We found the greatest value from using Glass has been in the assembly and quality areas, through the easy and quick hands-free access to the instructions and checklists necessary to assemble our individually designed tractors."

With Glass, the time it took to make one tractor fell by 25 percent; inspection times dropped 30 percent; and new hires could be trained in three days instead of 10.

"It's amazing," Gulick said.