IIRC, Eagle Tool started business 1843 or 1844. I have their product No. 2
framing square, which increased the heart beat of another Galoot about a decade
ago, although I can’t recall who that was other than he was writing a history of
the Eagle company and their product line and trolling for info on the Porch from
anyone who had one or more of their products. As I recall, they had a take down
square in their line by or before 1890. The Archives probably do have a few
postings about Eagle history or origins, and that other party would have a lot
more background on that question.
As for Twix …. the way your post reads, I detect a flavor of Stanley Co. market
behavior — maybe Twix were also buying up smaller competitors or their product
lines after WWII?