Identify the thread types

Identify the thread types

Growing up together -DICSA has compiled a simple Thread Identification guide to help you to identify common threads including BSP, JIC, ORFS, Metric, Flange, NPT. For measuring thread you need a caliper, a thread gauge and a DICSA chart to match your information.

Remember flange fittings have not thread, so you have to measure its outside diameter and thickness flange heads. Below, we show you the five simple steps that you should follow to identify thread:

Step 1 – Male or female

A male fitting will have the threads on the outside, while a female fitting will have the threads on the inside of the hex nut.

Step 2 – Tapered or parallel

Parallel threads are the same diameter from end to end, while the diameter of tapered threads gets smaller towards the end of the fitting. NPT and BSPT fittings have tapered threads, (DICSA NPT fittings have a hex mark to facilitate its identification).  UNF, ORFS and BSP have parallel threads. Metric fittings can be tapered and parallel.  You can make sure by using a caliper.

Step 3 – Pitch Size

A thread’s pitch size is the number of threads per inch or the distance between threads on metric thread types. A pitch gauge be used to calculate the pitch size, because is highly accurate.

Step 4 - Thread diameter

Measure the thread diameter using a caliper to determine the diameter and measure on the thread. Tapered threads have to be measured by the first and last thread and the parallel can be measured in any part of its threads.  Measure the outside diameter on a male thread and inside diameter on a female thread and check the DICSA chart. (measurements are approximate).

Step 5 – Thread Type Standard

Determine the thread standard. Use the parameters obtained in the steps 1, 2, 3 & 4 in order to find the appropriate thread in the DICSA Chart.