From the outside it was a worn and unimpressive looking machinists toolbox.
But inside was a treasure trove of tools--some dating back 100 years.
Note the c-shaped band at the top of most of the calipers in this grouping. It causes the legs to spring open and was invented in the late 1800s by C.P. Fay (later acquired by Starrett). To this day, nearly all calipers and dividers have this feature.
Look closely and you'll see the original owner's last name (Axel Aronson) engraved in the dial calipers in the right top drawer of the toolbox.

Brian Campbell likes tools. He likes using, inventing, and buying them. Don’t believe me? Then check out his TriHorse work station and the oak machinist’s tool box shown on this page. He bought the box at an estate sale in St. Paul, Minnesota. Another man had agreed to purchase the box and its contents for $50 and then backed out of the deal. Campbell—who had opened the box and seen some of its contents—immediately offered $100 for it and the seller agreed to the price.

According to Campbell, it was “an unimpressive looking oak tool box with a mismatched door and missing knobs. It was dirty and disheveled--tools a jumble inside.” But looks can be deceiving; the box turned out to be a treasure trove of some of the finest measuring and layout tools ever made. The tools date back to the 1880s and span the better part of a century. “They are obviously well-used, but so well made they are in good condition after many decades of service”. Campbell was surprised by how many nice tools the box contained. He was told that the tools had belonged to Carl Axel Aronson, a machinist who lived from 1883-1967 and worked at the nearby 3M plant.

Among the older tools in the box was a C.P. Fay caliper made between 1884 and 1887—the first to have a round steel band at the top. The band causes the legs to spring out against the adjustment screw, which makes the tool easier to adjust and more accurate. C.P. Fay was later purchased by Starrett which adopted the design for many of its calipers. Almost all compass type calipers and dividers built since that time have a “Fay spring” at the top to make the tool more accurate by causing the legs to press out against the adjustment screw.

I think it’s fitting that a finish carpenter—and not some collector—ended up with these tools. Instead of sitting in some display case, those that can be used for woodworking will continue to be used on the job. And they’ll be used by a guy who appreciates what the tools meant to their original owner.