Walters was the originator of factory-made undercutters after a collaboration with west coast users of new-fangled chainsaws sometime in the 1930s (if I recall). The early power saws could not make upwards angle cuts for completing felling notches due to carburetor fuel starvation so the notch saw cuts had to be manually chopped out with a modified axe. Chainsaws became much more capable by the 1950s prompting undercutters to become obsolete and manufacture was discontinued shortly after. Presumably your's is from the early to mid 50s when sales of them petered right out and unsold heads, that weren't tossed, began to accumulate dust on shelves at the backs of forestry supply stores.
Leonard Lee (who passed away recently) founder of Lee Valley Tools in Ottawa has (or had) a beautiful collection of NOS Walters and I would imagine his son Robin, who now runs the whole shebang, might be quite interested in adding a pristine undercutter to the collection if they don't already have one. Canada Museum of Science and Tech also has a magnificent collection of Walters and I don't recall seeing an undercutter in it but those folks only accept donations or issue tax receipts. Myself would love to have one but with the stickers and all on it it would bug me no end not to be able to use it.
Whenever someone posts a picture of an NOS desirable axe that they've found there is often an expression of interest that comes forth from Operator1975 but we haven't heard hide nor hair from him during the past 6 months.
