Yoke Adapter Problems

In the process of resolving another issue I've ended up with DIN to YOKE adapters from three different manufacturers. Now these things are simple devices. But I've discovered a question that neither I nor the other folks I've talked to have an answer for; widely varying performance. Two of the three leak at the tank, either all the time, or some of the time.

Here is their performance when using any of my yoke tanks.
DiveRite: When mounted the adapter rocks on the tank valve and leaks no matter how much manual force is applied when tightened. They do stop rocking, but still has a small leak.

Atomic: They rock when mounted on the tank valve but do not leak if enough manual force is applied when tightened.

Poseidon: When mounted they are flat on the tank valve; do not rock and give a tight seal using only finger pressure.

Now I suppose I could make them stop if I used a pair of pliers, or a wrench. But, I've always been under the impression that DIN to YOKE adapters were supposed to seal without the use of tools, other than hands.

Anyone have any insight on this?

When you say they rock, what exactly does that mean? Are they rotating about the axis of the yoke screw (the "roll" axis)? Are they rocking up and down (the "pitch" axis)? Or are they rocking side to side (the "yaw" axis)?

I have never seen a yoke adapter that was anything but stable when used on a yoke valve. Obviously, a valve that was not designed for yokes (i.e. one that does not have the "dimple" opposite the tank outlet) should not be used with yoke fittings, as without the "dimple", the attachment is not stable in the pitch or yaw axes. (Yoke fittings are never perfectly stable in the roll axis, but that is irrelevant except in cases of extreme abusers who insist on repeatedly rotating the yoke fitting while it is under pressure.)

Valves without the dimple to properly stabilize the position of the yoke screw should not be used with yoke fittings, even if you find a DIN to yoke screw in adapter to fit them. Valves with the dimple should work with *any* yoke.

These adapters are a very simple mechanical connection. If they leak, there is a problem somewhere. The two models I have are the DiveRite version and the XS Scuba Version. The DiveRite is better made, from a machinists point of view. Neither leak and both are solid with hand pressure only. If one did leak, I’d suspect the tank valve or o-ring, not the adapter.

Are you using rental tanks or your own?

It's acualy very simple
Din = Din where ever you go.
Yoke is not,there are 3 different sizes.
We had the same problem with the new Oceanic FDX10/delta4 with DVT
There was no way that we could get a tight seal, gave Oceanic a call and they sent me the European DVT witch is a lot wider and a bit deeper than the US ones.
As for the Poseidons(have 2 of them) they do fit the US valve but fit very poorly on ours.

Since there is no leak with one set of the adapters, nor any leak with my yoke regulators and no obvious deformity or damage to the valve or O ring I feel certain the problem is with the yoke adapters, not the valve, O ring, or tank.

Oh, yes all the tanks I tried these yoke adapters on had dimples and all provided the same results; no leak with the Poseidon adapters or with yoke regulators but did leak with the Atomic and DiveRite adapters, as described above.

The rocking is like the yoke adapters and the tank valves just don't quite match.

I didn't know there are different size yoke adapters or yoke valves. But, that seems to be the most reasonable explanation based on what I know now.

The dealer I bought these things from does business in both the US and other countries. So maybe the dealer doesn't know about the different sizing either.