Is UNC thread the same as Whitworth?

If you are struggling to find either a BSW thread (British Standard Whitworth) or a UNC thread (Unified National Coarse), it is useful to know that in almost all cases the two threads are interchangeable in practical terms.

Is Whitworth the same as imperial?

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.

What is Whitworth measurement?

A Whitworth wrench is sized according to the diameter of the shank of the bolt, not the head. A 1/4 W (Whitworth) wrench is actually a bit larger than a 1/2″ American wrench—0.525″ to 0.500″. As if that wasn’t enough, in 1924 it was decided that the heads of the Whitworth bolts were too large, so they were down-sized.

How do you identify Whitworth threads?

Use the Teesing thread gauge to determine the pitch or the TPI. The pitch is indicated in metric thread in millimeters. Whitworth thread is indicated in the number of threads per inch. Locate the possible TPI or pitch by matching the diameter measured with the thread tables below.

Are BSW and UNC interchangeable?

UNC and BSW have the same thread per inch value, accept for the 1/2″ size. Theoretical it would be possible to interchange them as they have the same amount of threads per inch. However due to the difference in thread angle, the connection would not be as strong as when using the proper combinations.

When did British cars stop using Whitworth?

Whitworth and BSF officially became obsolete in 1948 following an agreement between the UK, US, and Canada to standardise on the American UNC and UNF fasteners for future use.

What is a Whitworth spanner?

A whitworth spanner or socket is larger than one marked with the same size in BSF for example a 1/4 inch whit is the same physical size as a 5/16inch BSF. (approx 13.34mm),this occurs throught the sizes so a set of whitworth sockets or spanners will fit an equal number of BSF nuts and bolts.

What are the dimensions of the Whitworth thread?

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.

What does TPI stand for in thread count?

TPI stands for Threads Per Inch, Which means the total number of threads per inch measured along the length of a fastener. TPI is used only with American fasteners. Metric Fasteners use a thread Pitch. In general, smaller fasteners have finer threads, so the thread count is higher.