Anticarus
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I have a pair of steel 72s circa 1960 with archaic valves that I would like to replace with DIN compatible valves, however, they have tapered threads. Anyone know of a source for tapered thread DIN valves?
Tapered thread DIN valve?
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Faber Dude
Guest
In my opinion, it would be more worth it to down a few extra bucks on newer cylinders. The reason is because valves with tapered threads are becoming increasingly difficult to find. Since your cylinders are so well-aged, they probably won't serve you for too much longer before they fail hydro anyways. So it's probably not even worth the trouble.
Age in itself has absolutely no bearing on a steel cylinder failing hydro. Statements referring about the age of a steel cylinder affecting structural performance are totally incorrect.
If the cylinders are 1/2" NPT threads they are kind of a pain to inspect and clean, but it can be done.
I am not aware of any DIN valves that were ever made for 1/2" NPT threads. I have several European DIN valves (actually it was not called DIN when these valves were made) with tapered threads, but they are metric treads, not US pipe threads.
The most likely way of having a 1/2" NPT valve with a DIN fitting is to have the base of a DIN valve machined to the tapered threads. This is not very hard and most modern valves with the air intake in the center of the 3/4" NPS threads will have plenty of metal to work with. Any machine shop can do the job and it is acceptable technically and by the codes.
The cylinders you have are probably stamped for only 2250 psi and the volume is only 65cuft at that pressure. They are 71.2cuft at 2475psi.
Personally I would not bother changing the valves to DIN, but then again I have been using DIN fittings for over 35 years and haven't found any over all advantage to them. They are better in some respects, but also they are not as good as a yoke for a lot of ways. For most of my diving I have move back to yoke fittings.
Here are pictures of some tapered European valves that I own. They have a DIN connection, but as I mentioned it was not called DIN when I started using these valves. They are Draeger or Poseidon valves. Notice the reserve lever on the first two valves and on the center manifold on the double tanks.
Here are some European cylinders. The white cylinders are Draeger and the manufacturing hydro date is 1957. They pass hydro every time with better results than most newer cylinder.
Here is the adapter I had to have made to be able to hydro test the cylinders. The female threads are for 1/2" NPT threads. The male threads are metric and they are just a bit smaller than the 1/2" NPT pipe thread.
If the cylinders are 1/2" NPT threads they are kind of a pain to inspect and clean, but it can be done.
I am not aware of any DIN valves that were ever made for 1/2" NPT threads. I have several European DIN valves (actually it was not called DIN when these valves were made) with tapered threads, but they are metric treads, not US pipe threads.
The most likely way of having a 1/2" NPT valve with a DIN fitting is to have the base of a DIN valve machined to the tapered threads. This is not very hard and most modern valves with the air intake in the center of the 3/4" NPS threads will have plenty of metal to work with. Any machine shop can do the job and it is acceptable technically and by the codes.
The cylinders you have are probably stamped for only 2250 psi and the volume is only 65cuft at that pressure. They are 71.2cuft at 2475psi.
Personally I would not bother changing the valves to DIN, but then again I have been using DIN fittings for over 35 years and haven't found any over all advantage to them. They are better in some respects, but also they are not as good as a yoke for a lot of ways. For most of my diving I have move back to yoke fittings.
Here are pictures of some tapered European valves that I own. They have a DIN connection, but as I mentioned it was not called DIN when I started using these valves. They are Draeger or Poseidon valves. Notice the reserve lever on the first two valves and on the center manifold on the double tanks.
Here are some European cylinders. The white cylinders are Draeger and the manufacturing hydro date is 1957. They pass hydro every time with better results than most newer cylinder.
Here is the adapter I had to have made to be able to hydro test the cylinders. The female threads are for 1/2" NPT threads. The male threads are metric and they are just a bit smaller than the 1/2" NPT pipe thread.
Last edited:
james croft
Contributor
What Luis said !
I would use the tanks the way they are. They will last you for longer than you will probably be diving if taken care of.
I would use the tanks the way they are. They will last you for longer than you will probably be diving if taken care of.
The oldest tank I ever saw come through for hydro was a welding cylinder made in 1911. It still qualified for a plus rating. It was 90 years old at the time and I am pretty sure it will still be in service in 2011 when it turns 100.
I have 2 72's from 53 and 55. Still going the remark about the failing hydro is a crock-o-shiite!
oxyhacker
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The 3A specification was codified in 1909, best I can figure out, so 1911 would be almost as early as it could get. I had a 1914 "+" in my O2 rotation once. I hated to send it back but I seem to collect quite enough things without adding K tanks.
Scared Silly
Contributor
Again, a bunch of malarky.
Luis is spot on with his very nice post.
As for a source for 1/2 valves, try this guy. Never bought anything from him but he seems to have a good selection.
http://stores.shop.ebay.com/Scuba-Valves__W0QQ_armrsZ1
captain
Contributor
Back in the 90's at work I came across a steel commercial o2 K cylinder with an 1898 original date. That tank is probably still in service somewhere.
halocline
Contributor
Luis, very cool looking valves. I also like the rounded boots for the white doubles and would like to find a pair for my 72 doubles. I'd like something to protect the very bottom of the tanks from dings without adding a typical modern-style boot.
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