Tube and Wire Fittings Buying Guide

How to Measure Tube / Pipe – Tube Inserts & Wire Fittings: Buying Guide

A Step-by-Step guide to help you find the right size and type of tube/wire fitting for any application

1. What Size Do I need?

When buying any tube inserts, end caps & wire fittings the first thing you need to do is know how to measure tube / piping so you can determine which size of fitting you need. Depending on which type of fitting you decide on there are 2 measurements you will need to know; the outside / external dimensions, and for internal fitting tube inserts you will also need to measure the wall thickness / gauge size.

a. How to measure the outside dimensions


If you don’t have a Vernier you can also use a ruler to measure the dimensions

Measure the distance represented by the solid line to the outside of the tube/wire.

A. How to Measure the outside diameter

b. How to measure the wall thickness / gauge 

Wall Thickness

If the wall thickness of an insert isn’t listed on our website then it’s generally 1-2mm or 14/20 gauge.

2. Tube Insert Or External Fitting Ferrule?

When you know what size is needed the next step is to decide on which fitting you want. At BPF we offer the choice of internal fitting tube inserts or external fitting ferrules:

Tube Insert Or Ferrule3. What type of fitting do I need?

The final thing to decide is which type of fitting you need. Here at we BPF we have a range of different Inserts and ferrules for various applications:

Which type do I need