STI thread gauges for BSF, British Standard Fine

BSF is the fine series of the Whitworth system: the same 55° flank angle, but more threads per inch. Common on British vehicles and machines. STI gauges check the oversized thread that later receives a thread insert. It is a series of its own, because the receiving thread is larger than the working thread that follows.

VÖLKEL offers 11 versions, from BSF 3/16 x 32 to BSF 1" x 11.