British Standard Whitworth Thread Chart Pdfl
Melva Simons
Pipe thread is also different. The standard tapered pipe thread in the US is the NPT or National Pipe Thread. The British use the BSP or British Standard Pipe thread. Although similar, again, they should NOT, under any circumstances, be interchanged. The sad part of this thread confusion is the fact so many classic British cars, motorcycles, and yes, even airplanes have been butchered over the years by those not conversant with these thread systems (detailed later in this article).
British Standard Whitworth (BSW) is an imperial-unit-based screw thread standard, devised and specified by Joseph Whitworth in 1841 and later adopted as a British Standard. It was the world's first national screw thread standard, and is the basis for many other standards, such as BSF, BSP, BSCon, and BSCopper.
The Whitworth thread was the world's first national screw thread standard,[1] devised and specified by Joseph Whitworth in 1841. Until then, the only standardization was what little had been done by individual people and companies, with some companies' in-house standards spreading a bit within their industries. Whitworth's new standard specified a 55 thread angle and a thread depth of 0.640327p and a radius of 0.137329p, where p is the pitch. The thread pitch increases with diameter in steps specified on a chart.
With the adoption of BSW by British railway companies, many of which had previously used their own standards both for threads and for bolt head and nut profiles, and the growing need generally for standardisation in manufacturing specifications, it came to dominate British manufacturing.
The British Standard Fine (BSF) standard has the same thread angle as the BSW, but has a finer thread pitch and smaller thread depth. This is more like the modern "mechanical" screw[clarification needed] and was used for fine machinery and for steel bolts.
The British Standard Cycle (BSC) standard which replaced the Cycle Engineers' Institute (CEI) standard was used on British bicycles and motorcycles. It uses a thread angle of 60 compared to the Whitworth 55 and very fine thread pitches.
The British Association screw thread (BA) standard is sometimes classed with the Whitworth standard fasteners because it is often found in the same machinery as the Whitworth standard. However it is actually a metric based standard that uses a 47.5 thread angle and has its own set of head sizes. BA threads have diameters of 6 mm (0BA) and smaller, and were and still are particularly used in precision machinery.
The Whitworth 55 angle remains commonly used today worldwide in form of the 15 British standard pipe threads defined in ISO 7, which are commonly used in water supply, cooling, pneumatics, and hydraulic systems. These threads are designated by a number between 1/16 and 6 that originates from the nominal internal diameter (i/d) in inches of a steel pipe for which these threads were designed. These pipe thread designations do not refer to any thread diameter.
aa06259810