Choosing Air Fittings

Choosing an air fitting may seem like a simple task. For most people, they will use whatever came on their hoses and tools without even thinking about it. Although for many people the 1/4” Industrial fitting is a good choice, it simplifies what can be a fairly important decision affecting the safety and productivity of a workforce. In this guide we will cover how best to choose air fittings for your company.

A sample of different connector standards from the Milton catalog.

The first thing to understand is that a quality fitting matters. Proper machining and material selection will make a big difference in the longevity of components and their ease of operation. Air hose fittings may be connected and disconnected dozens of times a day for years, so their performance is a meaningful concern for any shop manager. Buy your fittings from a company with a reputation to protect. Many air fittings are white labeled products that have no underlying company behind them. Buy from a company that specializes in air fittings. Cheap knockoffs perform as expected of cheap knockoffs. Even expensive fittings can have their problems, but they are far fewer in number than the problems encountered with poor knock-offs.

A great thing to consider are safety couplers. Safety couplers differ from their normal variety by requiring a two step process to disconnect. The first step depressurizes the connection, and the second step separates the two pieces. They are sold by many companies and there are a variety of designs. Do be careful though. We have found that many of these, including expensive ones, don’t work very well and will lock up. It requires serious brute force in order to get these disconnects to disconnect. This is a problem as many people simply don’t have the brute strength to get it done. This means you shouldn’t go out and replace all your fittings, but start with a couple and try a few different brands or models. When you find one that your workers like, replace them all. I have found that reviews are not necessarily a good indication of what works well. I have found out the hard way that some expensive, well reviewed safety couplers did not last very long and were hard to use.

Another consideration is airflow. Most of these standard types move up to 40cfm. This will vary with the diameter of the hose. For a large nailgun, you will want a 3/8 or larger inner diameter hose to ensure that it is getting the air it needs. I have found that smaller hoses do work OK but you often miss the power that a large hose can provide. If you have very high cfm tools, like some impact tools, you can get air fittings that offer very high cfm. We are talking 90 or more cfm, enough to run a jackhammer. With a sufficiently large air hose and coupler, you can supply almost any tool with air without resorting to industry-specific specialty connectors.

Chart from Milton showing different connectors’ airflow characteristics.

There is another choice that come companies make which is to use high end fittings. Typically found in industry and research, these fittings are expensive and well made. For most companies, using a high performance fitting simply doesn’t make sense. The price performance ratio is low when using an air tool and the fittings are often subject to abuse which shortens their life. As a result spending too much money on a fitting can prove to not have any meaningful benefit.

Compatibility can be an issue. Be sure to buy a fitting that uses a commonly available standard for a connection. You don’t want to buy a fitting to find out that only one company makes a compatible fitting. There can also be the case where many companies make a compatible fitting, but the availability is low. This means that you are constantly vulnerable. Stick with mainstream fittings whenever possible for this reason.

Hopefully this article has provided some clarity on choosing air fittings for your production line. There are a wide variety of choices and it is important to think about these choices before simply settling on what is easy. You can significantly improve worker’s safety and speed with the right combination of air hose and fitting.