On 13 Feb 2004 18:34:11 -0600, Barry S. wrote:

I was in Harbor Freight today and they were having some sort of huge
sale as it the line was so long I refused to stand in it. But they
had a couple of displays of quick couplers for air tools. I grabbed
a male and female and tried to stick them together. Wouldn't go.
Noticed they had a couple of different sized on the male side, but the
female side of the connection appeared to be the same size.

How does this work? I thought there was only one size for quick
connects. Are their multiple sizes and are some compatible with each
other?
Toolbert gives a good explanation of the different series. As far as
quality - it's hard to beat Cejn. I was a distributor for them for
years and I think they make the finest coupling available - their web
site is http://www.cejn.com/ and if memory serves correctly the "310"
series is the industrial standard (with various sizes available). In
addition to sales, we also did tool repairs and used Cejn at our test
bench (and throughout the shop). These were coupled and uncoupled
literally hundreds of times each week and they lasted for years. We
ran over them with forklifts, stepped on them, dropped them and they
performed like the Energizer Bunny. They also make couplers with neat
features- they are "push to connect" meaning you don't need 3 hands to
connect them - the collar remains back until you push the male into
position and their "vented" line which holds the male and female
parts together until the pressure is reduced which eliminates the
"whip" when disconnected. They may be hard to find and a little more
expensive but how many do you have to buy? I have a couple on my home
compressor that have been on there for over 15 years so the cost per
year is mighty cheap - too cheap to fool with junk couplers.