Air Tool Connectors
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I have been asked several
times over the last few months what are the “standard” air tool connector used.
There isn’t really one standard, so this article gives some idea of the
options.
One of the basic problems is
that the thread of the air inlet port of most tools is either BSP (British
Standard Pipe thread) or NPT (National Pipe Thread) – the US version. Some time BSP fittings will fit into an NPT
thread, but it is something I rarely do. Clearly PTFE tape is your friend if
you find yourself in that situation.

This picture shows several connector
types that are available along with converter connectors. From left to right,
- British PCL male (available at any good tool
shop) on a tyre inflater
- PCL female to US Quick Connect male converter
- Quick Connect Male (sometimes called ”Standard
Industrial Interchange” connector) on a die grinder powered mini belt
sander
- Quick Connect female to PCL male connector
- US Mini Coupler male on a Sioux air drill (with
Rohm keyless chuck)
- Mini Coupler female to Quick Connect male
converter
- Quick Connect Female to Mini Coupler male
converter
Please bear in mind that I
have made all of the converters myself, they are only available to special
order.
US Tools almost always have ¼” NPT threads, both male & female Quick
Connect and Mini Couplers are available with this thread. We can usually supply
male Quick Connect fitting with male BSP threads, but female fittings (and
threads) are slightly more difficult to come by – we may not be able to supply
from stock.

In this picture we have,
- An airline swivel (part no 954) fitted to a 30
degree angle drill with a PCL male fitting on the end. The purpose of the
swivel is to allow the air hose to fall straight down to the floor which
makes the tool easier to handle.
- A rotating and swivelling fitting on a die
grinder (with a 1” scotchbrite wheel in the end – used for de-burring)
with a Mini Coupler male.
- A Mini Coupler male on a 3X rivet gun
- The female end of a ¼” air hose with female mini
coupler. The ¼” hose is much lighter and much more easy to handle than the
ticker hoses.
To get air to the tools you
require air hoses. The ¼” hose in the picture above has a ¼” NPT male thread
swaged onto the end – better picture below.

Some more examples below,
This is a fair cheap and
nasty coiled hose often supplied with cheaper compressors, again male ¼” NPT
thread swaged on the end. I would avoid these if you can – you will quickly
become fed up with its desire to go back to this shape, or to kink and stop the
air flowing.

One the left are the end of
the 3/8” diameter hose that is on the right, again male threads swaged on the
ends, protected by a rubber sleeve. This is quite a heavy hose that I try to
avoid using to drive air tools as it is tiring to hold up for very long.
So that is OK if you only
want to connect one air tool to your air supply. If you need more then a
manifold is called for – colloquially known as a “pig”. The picture below shows
a aluminium version with 3 Quick Connect female connectors. The input is a “fir
tree” fitting that the hose is pushed onto and secured with a jubilee clip. One
of the output hoses in the 2nd picture has the hose connected to the
male Quick Connect connector (that has a female thread on the end) in the same
way.


So that is the air tool end,
and the air hose connectors, what about the compressor end? Down stream of the
compressor I would recommend a pressure regulator is fitted with water trap.
The regulator on your compressor can be used, but its much easier to use a separate
(and better quality) version. I use this a lot when I am riveting to control
the pressure at the gun to make riveting easier – about 40 psi for 3/32” rivets
and about 60 psi for 1/8” rivets. Some people use pressure control valves on
the end of their rivet gun – I don’t like those and much prefer a reasonable
quality pressure regulator.
- Input from compressor
- Regulator screwed to the wall, balck cap on top
is used to select the output pressure, the gauge shows the output
pressure, while the bowl below is a water trap. This regulator is British,
so I have fitted PCL connectors – some people complain that PCL connector
do not allow sufficient flow, I have never found a problem.
- Out put to a Y splitter
- Input to a self winding hose reel, via a PCL to
Quick Connect adapter
- Output to pig above.

The feed from the compressor
has a ball valve – to de-pressurise the flexible lines – and Quick Connect
female connector, with the blue hose leading to the regulator above.

I hope this has been useful.
Most of the items pictured can be obtained from Gloster Air Parts on 01252
617484. We’re always happy to provide advice is you’re unsure as to what to ask
for.