I inherited this Tri-Tap-Tool years ago from my father in law who was a tool and die maker.
A web search shows a few other thread cleaning tools, notably Klein. I have a different one bearing the Efcor brand with a rubber padded handle.
The handle is marked "Tri-Tap-Tool" and the other side (not shown) says "Mfd. U.S.A." The shaft is engraved with a logo of TTT inside a triangle and the words "Pat Pend" underneath.
I cannot find anything about this particular tool or manufacturer, although an obituary claims Gilbert Nathan Griffith invented and patented the tri tap tool in 1954.
Link:
Gilbert Nathan Griffith (1920 - 1983)
The patent number and date cited in the obituary doesn't check out.
A web search shows a few similar tools, notably Klein, and I have another one bearing the Efcor brand with a rubber padded handle.