Push-on hose fittings—also known as push-lock, insta-grip, push-lok, or field-attachable fittings—allow for quick connections to fluid transfer lines. They are common in automotive assembly, packaging and manufacturing facilities, and pneumatic systems.
(It’s also worth noting that you might come across the term “push-lock hose.” While this term might be used casually, the push lock refers to the fitting and not the hose.)
Push-on hose fittings are popular because they don’t require clamps or crimp sleeves for installation. They are also designed to be safer and cut back on assembly time, but they can require an extensive amount of pressure and physical effort to lock into place. For this reason, this guide will discuss tips for making the easiest connection. Before you consider this, it’s imperative to find the correct size of fitting.
Comparing Sizes of Push-On Hose Fittings
The sizing chart below reflects general sizing for push-on hose fittings. These sizes can be compared to AN sizes in the second chart, although it’s important to note that AN fittings use a 37° flare as the sealing surface. You should not use AN fittings with different flare-type fittings. If you’re not sure how to measure a hose fitting, follow this guide.
| Size Number | Inside Diameter (I.D.) |
| #4 | ¼" |
| #6 | ⅜" |
| #8 | ½" |
| #12 | ¾" |
| #16 | 1" |
AN stands for Army-Navy. In size fittings, it’s measured in 1/16" increments and can refer to either the outer diameter (O.D.) of a tube or the inner diameter (I.D.) of the hose with which it's being used.
| AN Size | Hose I.D. - Tube O.D. | SAE Thread Size |
| -4 | ¼" | 7/16"-20 |
| -6 | ⅜" | 9/16"-18 |
| -8 | ½" | ¾"-16 |
| -12 | ¾" | 1 1/16"-12 |
| -16 | 1" | 1 5/16"-12 |
How Push-On Hose Fittings Work
These types of fittings are made with a custom set of barbs that attach the hose to a number of different connections, and are made of different metals such as brass and steel to meet the needs of various fluid types. Hoses also come in a variety of materials, with a braided texture that is designed to expand over the fitting when it’s pushed into place. Pulling on the braid after a fitting has been inserted causes the braid to shrink tighter over the fitting, making it more secure.
Tips for Installation
Finding the right balance in order to secure a hose on a push fitting can be a challenge, but these tips should help.
Monitor temperature.
A colder hose will be less likely to expand over a fitting, but using powered heat could compromise the connection. For smaller hoses, keep the hose or hose end somewhere in your pocket to keep it warm before use. For larger fittings, consider using hot water that is just below the boiling point. Allow the hose to soak for a few minutes.
Consider size.
Whenever possible, try to work with larger hoses and hose diameters. They’re easier to grip in your hand and expand better.
Maintain a constant pressure.
Move the hose over the fitting in one motion, applying constant pressure to avoid the hose locking over the first barb or two without reaching the last barbs. With this in mind, it’s also worth noting that additional barbs are not always better. According to the Brookhaven National Laboratory, more flexible tubing can more successfully grip to a single barb.
Use a vise.
In situations where it’s possible, use a vise to get a better grip and a plastic vise jaw when possible to avoid damaging the hose. Don’t use a vise in situations where damage to the tube might be inescapable.
Don’t use greases or oils.
Most lubes could compromise your connection or cause other issues and should not be used. In some cases, a temporary, water-based rubber lubricant that dries without causing connection issues may be applied.
While push-on hose fittings present some challenges, they can prevent injury due to a lack of sharp edges, and usually do not require additional clamps or crimp sleeves.
Product Compliance and Suitability
The product statements contained in this guide are intended for general informational purposes only. Such product statements do not constitute a product recommendation or representation as to the appropriateness, accuracy, completeness, correctness or currentness of the information provided. Information provided in this guide does not replace the use by you of any manufacturer instructions, technical product manual, or other professional resource or adviser available to you. Always read, understand and follow all manufacturer instructions.