To most people, the letters, numbers and small geometric shapes forged into the tools' handles give few clues as to their provenance. Luckily, there's Alloy Artifacts, a website dedicated to documenting the implements that kept America's machines running smoothly through the 20th century.
Not sure what you've found? The site has numerous photos of tools along with their intended uses; sometimes you'll even find links to their original patent filings. The odd tool you see above was made by Blackhawk Manufacturing in the early 1920s. According to Alloy Artifacts, it's a "model 6218 9/16 speeder socket wrench with a sliding extension" used to remove the engine base bolts of Model Ts.
Several toolmakers are profiled on the website, including Hindsdale Manufacturing, which made the socket set you see here sometime between 1919 and 1924. You'll also find myriad photos and descriptions of products made by Snap-On, Hinsdale, Duro, and Cornwell just to name a few.
Block off a couple of hours and lock yourself away in the garage. Looking through the site and imagining using the antique tools is time-waster on par with YouTube and eBay.
[Source: Alloy Artifacts via Hemmings Auto Blogs]