442377-A is referenced by 2 patents.

442,377. Set - screws. STANDARD PRESSED STEEL CO., Jenkintown, Pennsylvania, U.S.A. Aug. 13, 1934, No. 23320. Convention date, July 16. [Class 89 (i)] To facilitate turning with the fingers, the sides of a set-screw having a tool-receiving socket of less extent than the diameter of the head are knurled or otherwise axially roughened. Reference has been directed by the Comptroller to Specification 125,200, [Class 89 (i)].

Improvements in socket head cap screws
Application Number
GB19340023320 19340813
Publication Number
442377 (A)
Application Date
August 13, 1934
Publication Date
February 7, 1936
Standard Pressed Steel Co
F16B 23/00
F16B 23/00
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