BRITISH STANDARD WHITWORTH TAP & DIE SET BSW TAP DIE SET - LEFT HAND MUST FOR THE CLASSIC & VINTAGE OLD CAR / BIKE RESTORER ETC SIZE: 3/16" to 1/2" SET CONSISTS OF : SET OF 3 TAPS & SPLIT DIE OF (OD 1" & 1.1/2") 3/16" x 24 TPI, 1/4" x 20 TPI, 5/16" x 18 TPI ,3/8" x 16 TPI, 7/16" x 14 TPI, 1/2" x 12 TPI, PLUS FREE THREAD CHART. THESE TAP & DIES ARE MOSTLY USED IN OLD AND BRITISH CARS AND MOTORCYCLES RESTORATION. EMAIL US FOR ANY HARD TO SOURCE TAPS/DIES AND DIENUTS. EMAIL US FOR ANY QUESTION ?