Updating My Air Fittings

[RonL]

I have hose crimping tools. I noticed that Milton did not have any V style fittings with hose barbs. I looked at the CEJN fittings that had hose barbs. I ordered some of the 320 series that is the European high flow standard ( Milton V series). The fittings were compact and looked nicely made. The sleeve pushes back and the snaps into place when you push in a plug. When you pull back on the sleeve, the plug pops out to a second position to drain the air. when you push the sleeve forward the plug can then be removed. Very nice.

However:

When they say the barb is 10mm- 3/8, it is a full 10mm. 3/8 inch hose is usually listed as 9.5mm. While I made up hoses with the right size ferrules and regular 3/8 barbs, I could not do the same with the 10mm barbs. I went up a size on the ferrules and was able force in a couple with major effort. Another i could not for the life of me get the barb in. I also had to ream out the hole in the end of the ferrule.

Something to be aware of!

Parker Hannifin makes the RF series to the European high flow specs. I'll have to pay a visit to my industrial supplier.

[RonL]

Something you should be aware of if you are considering Milton V fittings.
They are made in Taiwan. Usually products made in Taiwan are very well made, as opposed to products made in mainland China. However, the pipe threads on the Milton fittings are out of spec. They will screw all the way in without tightening. They only snug up when they bottom out. If you back them out a fraction, they will rattle in the fitting. I used some of them because I had work to do. I put extra teflon tape on them and screwed them down all the way. Some of them still leak air. I sent two emails to Milton informing them of this and heard nothing. I asked them to replace the full box of fittings that I had. I heard nothing. I am replacing the Milton V fittings with Parker and CEJN fittings.

[platypus20]

Personally I would not allow Milton V type fitting in the shop, everyone I ever had leaked out the fitting end, not at the start, but soon after. Numerous web postings citing similar problems. I went with the Amflo T style, the flow numbers were very close, are much better made and 2-3 years into it, not a single leaker.

[RonL]

So far the ones I'm actually using are working OK. Time will tell. I have Parker and CEJN replacements ready to go if they fail. I'm replacing the one that did not thread in properly.

I heard so much about the qualities of polyurethane hose that I bought a Milton "polyurethane" hose. That is how they list it ( with the quotation marks). I thought it was terrible. I got a Kuriyama polyurethane hose and it was a world of difference. Beautiful and tough hose.

I'm less than impressed with Milton.

[Ironman]

I have had no problems with Milton M but I found it best to use a steel rather than brass male end. For impact or chisel use the steel balls in a Milton chuck will create divots under a vibrating load in a brass one.

Also because I run 165psi air, I have had a problem of the chuck blowing off the hose, usually when I am gone, and when I start the compressor I have to hunt the shop for the chuck and barb.
I began to use a Pex clamp ring (I have the pex tool) on my hoses.
Now not only does the hose stay on the barb, but the damn hose clamp does not hook on everything when it's reeling in on the hose reel. It's a clean smooth setup.

The non tapered pipe thread is a metric/imperial measure quandary.
No one ever invented a metric pipe thread, but they HAD to be different, so they used inch thread without the taper and called it Japanese straight pipe, usually has a sealing washer on a metric car for instance. I find lots of black iron pipe fittings coming from Thailand without a taper thread.

[RonL]

The pipe threads on the Milton fittings are tapered, you can see it. The problem is that they are undersized so much that you cannot screw them down to an interference fit. They bottom out before they tighten on the threads. I suppose you could put an o-ring on the top of the threads to attempt to seal them, but that is not how they are supposed to work.
After I crimp on a ferrule I put on a shrink wrap collar over the ferrule and a couple of inches down the hose. This helps to prevent snagging and works as a bend guard. On some I put a 3 inch, 2 1/2 inch, and a 2 inch shrink wrap collar as a bend guard.

[RonL]

I realize that this is an older thread, but I thought that an update would be useful.
I have used the industrial style fittings for at least 50 years. I used them in 1/4, 3/8, and 1/2 inch nominal sizes. I used 1/4 on smaller tools that had 1/4 NPT inlets. I usually used 1/4 ID hose on these. I used 3/8 nominal couplers on larger tools that had 3/8 NPT inlets. I used 3/8 hose with these. I used 1/2 couplers on large tools with 1/2 couplers and 1/2 hose.
Since I was replacing some couplers on my 1/4 hoses I decided to look at the high flow couplers. They were reported to flow more air that the 3/8 industrial couplers. I ended up replacing all the 1/4 and 3/8 plugs on all the small and medium sized tools and jigs that I own. I left the 1/2 as they were. I use 1/2 on larger tools and on the inlets to my air tanks (air pigs). I have three portable air tanks that I position near where I am working. I have a 30 gallon tank on wheels, a 12 gallon tank on wheels, and a 10 gallon hand carried tank. The 30 gallon tank has a 3/4 Chicago twist lock with a 1/2 adapter on the inlet side. I can feed this from my diesel compressor or from my stationary compressor. The other 2 tanks have 1/2 inlets that feed from the compressors. I generally run the air tanks at 125 PSI. The outlets have regulators on them that feed three way 1/4 and 3/8 couplers. Since the air tanks are close to where I am working I run relatively short hoses at 90 to 100 PSI.
I bought a 500 foot roll of Kuriyama PNEU-THANE 3/8 polyurethane (5096 blue) hose. I made a number of hoses up from this. I used Parker and CEJN hose barb fittings. The model Parker fitting I used are no longer available.
The Kuriyama hose is extremely tough and flexible. It is rated class A rated outside and inside for oil resistance. The most critical thing about it in my opinion is that it is about the same OD as 1/4 rubber hose. You can have one 3/8 hose that will adequately feed all your 1/4 and 3/8 tools.
I have had no problems with the fittings leaking. I believe the problems with leaking are related to the fact that some connectors will connect to multiple styles of plugs. The industrial style plug will only go in partway and seem loose. The air demand on some air tools will hammer the air fittings. The aluminum plugs don't appear to be able to stand up to this use.
If I was starting out again I would start by installing hardened steel high flow plugs on all my 1/4 and 3/8 inch tools and jigs. I would install a quality high flow connector on my hose.

[RonL]

As I said previously, although the fittings have an effect on air flow, the hose diameter may play a larger part. A long length of 1/4 hose will not adequately supply a larger air tool. If you are only going to have one hose, a 3/8 hose will better serve your needs.