British Standard Whitworth (WHIT or BSW)
The original 19th century British coarse-threaded industrial bolts designed to hold locomotives together. Because of their coarse pitch, they are prone to vibrating loose, so are little used on motorcycles. Most sizes are interchangeable with UNC threads except ½” but do have a slightly different angle on the thread, however, this practice is ill-advised with stress fixings such as brakes or suspension components. Available in steel and stainless.