How much wall reduction is necessary?

Tight tube joints are necessary on all kinds of projects. For example, they are vital for pipe lines that will carry any kind of gas or liquid. The goal here is to ensure there is no risk of a leak or rupture. A joint is just as important though with products like handrails, bicycle frames, and furniture. Here they have to provide stability and avoid weak points. To get the right joints you may need tube expansion.

Calculate the wall thickness

Before you do anything you need to get an accurate idea of how thick the wall of the tube is. The manufacturer should be able to tell you this but you may want to do your own checks to.

The easiest way to determine the wall thickness is to begin by measuring the outer diameter (OD). Then you can measure the inner diameter (ID). A simple subtraction of OD minus ID should give you the size of the wall. It may be a good idea to take measurements at different points on the tube circumference to ensure the wall is consistent.


Tube expansionOnce you know the wall thickness of the tube you can see how much you may need to adapt it to create the joints. This can tell you what kind of tube expansion service you need. Again it is vital you get an exact idea of how much wall reduction is necessary. If you go too far here the joints won’t be tight enough. As a result, leaks or weakness can occur.

In most cases you won’t need to reduce a tube by more than 10%, regardless of the material you are working with. Only a few metals can even allow a wall reduction over that amount. For example, it can be possible to reduce 6061 aluminium by up to 12% in some cases.

With the majority of metals a reduction of between 5% and 8% will be sufficient. This includes substances like carbon steel, admiralty brass, and titanium.

What you do need to think about here is metal hardness and lubrication. The first could result in cracking if you try to expand the tube hole too much. The latter is often vital to protect expanders and the surface of the tube.

Ask us for help with tube expansion and more

Multiform Tubes Engineering Ltd is the UK’s leading name for tube manipulation. We can offer services for many industries and a huge array of applications. Our goal every time is to deliver quality tubing that you can rely on.

In terms of adapting tubes, we can provide everything from tube expansion to reduction, tapering, swaging, and bending. What this means is clients can come to us for a full range of solutions. Even if you need to create complex products with lots of bends and precise ends, we can cater for you.

So, get in touch today if you want to talk to us about your tubing needs.