I have that article on DVD (and I mentioned it earlier in this thread) from The Chronicle (The Chronicle of The Early American Industries Association, Vol. 37, No. 4, December 1984, pages 70-71, "Yerkes & Plumb" by Dan Comerford) about the history of Plumb, as told (or written) to the author by Fayette R. Plumb II (the grandson of the original F.R. Plumb).
Here's what FRPII said about Permabond:
"
1954 -- Plumb Permabond appears as black material in Leader Tools -- marketed until 1955 -- L81 only."
"
1955 -- Permabond in all tools of top grade. Fiberglass handle F55 and F55R appear -- solid fiberglass handle."
Some other dates from his timeline that might help with figuring out when a Plumb tool was made:
"1910-1911 -- Plant built in St. Louis, Mo., to manufacture axes."
"1920 -- Plumb changes to trademark colors of black head & red handle"
"1940 -- All tools stamped Genuine Plumb"
"1942 -- 'Victory' finish introduced & for duration of WWII"
"1960 -- St. Louis plant is closed and sold. All manufacturing shifted to Philadelphia."
[
YesteryearsTools shows some of the labels associated with the St. Louis plant.]
Mr. Plumb also disclosed that
Plumb made the following brands, among others:
Blue Grass
O-V-B (Our Very Best)
Diamond Edge