BS

Specification for aircraft material. Fork joints (high tensile type) (for sizes No. 4 B.A. to 3/4 inch B.S.F. inclusive)
standard by BSI Group, 02/19/1943

Specification for 100 degrees countersunk head high nickel-copper alloy rivets
standard by BSI Group, 10/31/1973

Specification for carbon steel worm drive clamps for aircraft
standard by BSI Group, 01/31/2015

Specification for 4/1 nickel-chromium steel tube (1150 N/mm^2)
standard by BSI Group, 10/27/1972