From Alloy Artifacts:
Fairmount Tool and Forging was founded in 1917 in Cleveland, Ohio, and became well known as a contract manufacturer for automobile tool kits. The company also specialized in tools for automobile body work.
Currently we have only very limited information for this company. The company is listed in a 1931 "Corporations and Directors" directory, which indicates that Fairmount Tool and Forging was incorporated in 1917, with J. Wentworth Smith as President. A small brochure from 1928 for their automobile body tools gives the company address as 10611 Quincy Avenue in Cleveland, and offers their new auto body work instruction manual "The Key to Metal Bumping" for $0.25 postpaid. (As an aside, this little book became very popular, and remains in print today!) The brochure shows the use of an inverted diamond logo enclosing the "FTF" company initials.
Based on information printed in the 1953 Third Edition of "The Key To Metal Bumping", by 1953 Fairmount had become a subsidiary of Houdaille Industries, an industrial conglomerate. Fairmount remained as a division of Houdaille until July of 1984, when the company was acquired by the Martin Sprocket and Gear Corporation. The Fairmount operations were renamed as the Martin Tools division, and the line of tools continues in production today under the Martin brand.
The information above does not support a tie-in with MAC tools.