1/4 thread for pressure transmitters

Threads - types

There are many types of threads In the following overview we present the most commonly used thread forms.

In terms of the system of measurements are two types:

• G threads (inch) - pipe thread, thread angle is 55 or 60 degrees, and thread pitch is the number of turns per inch

• M (metric) threads - the thread angle is 60 degrees and the thread pitch is given in millimetres.

In terms of position:

• male thread - positioned on the outside

• female thread - positioned inside the hole

In terms of pitch:

• cylindrical thread - formed on the surface of a cylinder

• tapered threads - formed on the surface of a cone

In terms of pitch:

• fin thread - smaller thread pitch

• coarse thread

• normal thread

Thread form in terms of country:

• bsp threads (british standard pipe) – Great British standard, for example pipe threads where pressure-tight joints are made on the threads

• npt threads (national pipe straight threads) – American standard

Can bsp and npt be used together?

These thread types are misaligned, which can result in threads that are only partially fastened. Although 1/2 and 3/4 NPT and BSP sizes have the same pitch, there are differences in thread forms and thread angles, causing connection problems.

Most commonly used threads

In Poland and other countries that use the metric system, the most popular threads are integer multiples of millimetres, such as:

• Thread G1/2

• Thread G1/4

• Thread G1/8

What size is a 1/4 thread?

A 1/4 thread is 6.35mm with a pitch of 28.