Whitworth thread – chart, dimensions, applications

What is a Whitworth thread?

Whitworth thread is the British national thread type developed in 1841 by Joseph Whitworth.

Prior to that, there were no generally accepted standards. Each company had its own standards, which led to a lot of confusion.

Whitworth threads were the answer to this difficulty, and the fact that we still use them today is testament to the effectiveness of such standardisation.

What are the designations of Whitworth thread?

Here are the most common designations of the Whitworth thread:

• BSW (British standard Whitworth) - plain Whitworth inch thread, cylindrical; 
• BSF (British Standard Fine) - Whitworth inch thread, fine thread; 
• BSPP (British Standard Pipe Parallel) - Whitworth pipe thread, cylindrical; 
• BSPT (British Standard Pipe Taper) - Whitworth pipe thread, tapered.

The Whitworth thread standard is described by specific abbreviations that you will find on today's construction parts.

What is the difference between Whitworth pipe threads and Whitworth inch threads?

The main difference between Whitworth pipe thread and Whitworth inch thread is the difference in their standards and dimensions. Many people make the mistake of distinguishing between Whitworth threads. Thus, they pick the wrong thread sizes when using charts with standards.

What are the dimensions of Whitworth thread? Whitworth threads chart

Below you will find separate charts for Whitworth pipe and inch threads.

Whitworth inch threads chart

Whitworth pipe thread chart

What is the application of Whitworth thread?

Whitworth thread is used in military and multiple different types of machinery. As for the traditional BSW thread, it was first used on Royal Navy gunboats. And the more modern (due to its smaller pitch and depth) BSF thread was used in precision machinery and installations.

However, nowadays, inch threads in Europe are mainly used for the mechanical connection of hydraulic and gas installations, which is where you will encounter them most often, as they have become the standard in these industries.