French tank valve on US tank???

[eskimo3883]

Hi,

Has anyone ever tried to mate a vintage French tank valve (European tapered threads) to a US tank using an adapter of sorts?

All thoughts welcome.

[WD8CDH]

Which Euro thread? If it is one of the smaller ones, a bushing probably would allow adapting to 3/4" NPS SCUBA threads. I did a German valve to one of my rebreathers tanks in the past.

[eskimo3883]

It costs too much to ship tanks from France of unknown quality so I have a collection of just French valves from the 50's and 60's. I thought I might have a chance to use a bushing to mount a French 1950's tapered thread valve. The French version has a very large taper.

I also have later valves designed to be mounted with o-rings. I assume these are metric. They are close to the current US standard so I doubt there room.

An obvious alternative would be to find an extra euro tank in the states. Anyone have extras?

[hallen41]

I took my spiro apart and got a friend of mine to put the nozzle on a lathe. He had to shave off about 2 thousands of an inch. It took the crome off but it fits US tanks just fine.

[eskimo3883]

My goal is not to get a French reg to seal but to mount my way-cool French valve with French tank straps yet still have DOT tank for fills, etc. I stole the picture below of the US version but the only difference is the French one has tapered threads.

[eskimo3883]

The US and French valves both have tapered threads. I should have said the French one has metric tapered threads (very tapered).

[WD8CDH]

Can you measure the threads? Large and small end diameter, length and pitch? If I can identify them, I may be able to find a tap.

[hallen41]

Sorry, I mis-undersood what you were trying to do.
A good machinest may be able to make an adapter if there is enough diffrence between the French thread size and the US size.
The fill them yourself Idea is the simplest method.

[YankDownUnder]

I have a 1958 French tank with the Gagnan side J system. It is used with a French Mistral and harness. The nylon seat is a bit hard now, but it works. I don't think it is a practical idea to put it on a 3/4 " tank, because I would still not have the required burst disc, so I just decant. I would just end up with something which is not original and dosen't work too well anyway. My French Mistral is rarely used and is sort of a show piece. I had the valve pulled and and inspected it. It was tested but not stamped. As it is safe, I just whip fill it when I want to use it.

[eskimo3883]

I am slow to catch on but the solution is getting to be pretty clear.

Anyone in the US have a French tank with tapered threads they are willing to sell or trade with?

[seakrakken]

how much does it cost to ship a tank from France?

[scaph]

Bob,
From France to US, by priority mail:
15 kg = 126,10 euros
20 kg = 149,10 euros
25 kg = 172,10 euros
30 kg = 195,10 euros

More than 30kg, you have to check with UPS, fedex ......

[WD8CDH]

My goal is not to get a French reg to seal but to mount my way-cool French valve with French tank straps yet still have DOT tank for fills, etc. I stole the picture below of the US version but the only difference is the French one has tapered threads.

Would this valve be way-cool enough to solve your needs? It fits US tank threads.

[eskimo3883]

Hi Ron,

Have never seen that valve before. Interesting, but I am set on using my vintage valve.


Hi Scaph,

Shipping is quite high from Europe but your numbers are a lot more reasonable than others I have seen. If you have a divable vintage French tank with tapered threads available I am interested.

I bought a set of aluminum French doubles about two years ago. The seller was too afraid of shipping without a signature on delivery so he said it had to go FedEx. The shipping jumped to 500 EUR. These were a special set, and it was almost same price to fly, so I made a vintage dive vacation out of it. Flew carry-on only to France, picked the tanks up Toulon, and carried back the tanks and a pile of other French dive gear as luggage to further save in shipping costs. Baptized my wooden goggles off Antibes and my Squale mask at Bandol. Dumas Museum at Sanary. Week in Paris for the wife. A very good time.

I think I could have brought one tank for free as luggage but aluminum twins in a wooden crate came in at 32 Kg. This was 2 Kg above the limit for a single piece of luggage and should never have been allowed on the plane. When I told them I could not break them down further Air France just put them on the plane anyway (with a 100 EUR charge). I was in my seat having a glass of wine when just before the doors closed the French TSA pulled me off the plane. They held a 747 full of people for over 30 minutes while I got to prove the tanks were empty. I left the valves open but when I checked in I could not get anyone to inspect the tanks. Got a few cold looks when I re-boarded the plane.

[WD8CDH]

Could you measure the smallest and widest part of the tapered threads? From that, I can tell if it is even feasable to make an adapter. For example, a 1/2" NPT valve is anout .804 small end and .845 at the wider part of the threads. I have made adapters for 1/2" NPT valves to US SCUBA tanks in the past. Adapters are legal to the DOT.