It is a wing panel install alignment tool/jig used on the Boeing 747 line helps the mechanic hold and align the blank panel when locating to drill up for fastening it.The letters FAJ = Fab Alignment Jig
Am thinking that "Location: Everett Wa" provides a hint as to why Slick111 would know about 747 builds
Aircraft tool design & manufacturing brings back some fond memories & recollections.

Hence, hope I can be forgiven the following digression:
My Father was a Boeing Tool Design Engineer, and spent his entire career at Boeing—from 1946 to 1981—designing many of the tools that were used to build the airplanes, everything from small tools, like those abv ^, to the giant overhead crane (jigs?) that held & positioned the wings, tail and super-structure together.
He was always very proud of his work, as were all his Boeing men's league golfing & bowling buddies.
They all got jobs around the same time at Boeing—my Father actually met what became his two Boeing-lifelong-career closest friends while the three of them were sitting in the Wichita Boeing Plant employment office waiting room, in 1946, unbeknown to each other, waiting to be interviewed.
All three were offered jobs; one of them had a Buick convertible coupe and so they hopped in it and went out and rented a home together.
Then around 1949/50, all three somehow got themselves transferred up to Seattle's Boeing Plant 1, where they found a great bachelor pad right on the beach next to the Alki Point Lighthouse. And where my Father later met my Mother (a Boeing accounting secretary; picture form-fitting stretch in-the-boot ski pants & cats-eye eyeglasses), while on the ski train that used to run from Seattle up to the Snoqualmie Pass ski areas, back in the 1950's.
Or me & my sisters wouldn't'a been born. Phew!
As I recall, they originally worked on the B-29, XB-44, B-50 & B54 Superfortress', and the B-47 Stratojet, the B-52 Stratofortress, as well as the XB-56 & XB-59 Strategic Bombers, before transitioning to the 707.
But I still haven't forgiven him for volunteering—in 1962, while acting upon his inspiration from President Kennedy's
"Ask not what your Country can do for you ~" &
"We will go to the Moon and do the other things~" speeches—to uproot and move our family from Seattle -to- New Orleans

for 5 years, after Boeing & Chrysler won the NASA contract to build the first (bottom) stage of the Saturn V S-1C Moon Rocket, which they built at NASA's 832-acre Michoud Assembly Facility (MAF), in the Michoud area of eastern New Orleans.
https://mafspace.msfc.nasa.gov/history-maf/
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