Need yoke solution for Sherwood (7/8) tank

[WD8CDH]

It's not an engineering reason. Back in the 70's, the 5 thread DIN was the norm and used regularly at 4500psi. I even have a Poseidon regulator with the 5 thread DIN, rated for 4500psi, that won't even work with a "300 bar" 7 thread DIN. The 7 thread DIN came into use in the SCUBA industry later to prevent the few DIN regulators that were unable to handle pressures over 3500psi from being connected to 300 bar tanks. It is not a DOT requirement. The 7 thread DIN is no stronger than the 5 thread DIN as far as pressure handling capability, in fact it is actually weaker on impact resistance. Thermo's catalogue shows service pressure based on installed burst disk but the actual service pressure of the valves themselves is the same for all versions.

You may have asked Northeast SCUBA the wrong question. What you need to put either "300 bar" DIN, "232 bar" DIN or Yoke regulators on your tank is a Thermo 8082RH-5250 Modular Valve (7/8" inlet thread) and a Thermo 9020RH "H Connector Attachment". And a Plug for the unused port. These parts will easily handle 3500psi and more.

As far as removing some threads from a "300 bar" DIN valve, you will loose the chrome and also the body probably doesn't have the dimple for the yoke screw.

You may also be able to find a machinist to re-thread a K valve to 7/8"-14 UNF thread and change the burst disk. That is legal.

But.....as others have said, the better solution is to convert the regulators to DIN. You can put a DIN to Yoke converter on the regulators in the field without tools if needed.

 

[donooo]

The reason I don't want one rogue tank and one rogue reg is so I can put any reg on any tank, either any of my family's other tanks or a rental tank, and not have to worry about disassemby of my regs and yokes.

You already have one rogue tank, its called a HP 100. It is a special and unique tank, you have none other like it. If it is of no use to you because it is "special" get rid of it. I dive one because it is special. I like the 300bar din and I like the weight. I carry it around the northwest in my RV. I have five regs and they are all Din, I have three adapters for the AL 80's in my life and I only take one on vacation

Sell it,,,,, don O.

 

[MajorJohnson]

You may have asked Northeast SCUBA the wrong question. What you need to put either "300 bar" DIN, "232 bar" DIN or Yoke regulators on your tank is a Thermo 8082RH-5250 Modular Valve (7/8" inlet thread) and a Thermo 9020RH "H Connector Attachment". And a Plug for the unused port. These parts will easily handle 3500psi and more.

I see how that would work.

As far as removing some threads from a "300 bar" DIN valve, you will loose the chrome and also the body probably doesn't have the dimple for the yoke screw.

You may also be able to find a machinist to re-thread a K valve to 7/8"-14 UNF thread and change the burst disk. That is legal.

But.....as others have said, the better solution is to convert the regulators to DIN. You can put a DIN to Yoke converter on the regulators in the field without tools if needed.

Yes, I realize I will lose the chrome plating from the edge of the threaded portion and expose the brass, but I'm assuming that this is cosmetic only and will not lead to some catastrophic corrosion.

Now re-threading the tank threads on a valve never occured to me. Do you know if once the 3/4" outside threads are machined off to their deepest "valleys" if the resulting diameter is large enough to form the outside "peaks" of the 7/8" thread?

 

[Jimmer]

Now re-threading the tank threads on a valve never occured to me. Do you know if once the 3/4" outside threads are machined off to their deepest "valleys" if the resulting diameter is large enough to form the outside "peaks" of the 7/8" thread?

Yes, it will be fine, there is more than enough material present.

 

[fatnold]

Hi

I am looking at the exact same problem. what did you end up going with?

 

[MajorJohnson]

Hi

I am looking at the exact same problem. what did you end up going with?

I decided to machine off the last few threads of the DIN 300 connection on the tank valve to become DIN 200 length. This would allow me to use the spin-out adapter. I have not made the detailed measurements yet. When I eventualy do the job, I'll post the results.

 

[marchand]

make sure the valves have the little yoke detent dimple in the back. if they don't you will need to machine that too.

 

[AlainD]

I guess no update on what happened ? Hope majorJohnson didn't have an accident on his experiment. I too am in the same situation.

I'm about to buy 2 older HP100 steel 7/8 thread for a great deal (just hydro), but my regulator (Aeris AT600) DIN converter is outrageous $120 on leisurepro (OCNDAK99) - more than I paid for first stage new on ebay! I need to see if I can find one cheaper, maybe another compatible brand as some are around $40. Having to carry a DIN to yoke on travel is an added hassle. Would love to have DIN200 on those tanks instead....

 

[tbone1004]

I guess no update on what happened ? Hope majorJohnson didn't have an accident on his experiment. I too am in the same situation.

I'm about to buy 2 older HP100 steel 7/8 thread for a great deal (just hydro), but my regulator (Aeris AT600) DIN converter is outrageous $120 on leisurepro (OCNDAK99) - more than I paid for first stage new on ebay! I need to see if I can find one cheaper, maybe another compatible brand as some are around $40. Having to carry a DIN to yoke on travel is an added hassle. Would love to have DIN200 on those tanks instead....

not possible to get 200bar din, don't even bother trying. If the adapter is not practical, get either a new first stage that is din *easily sourced for around $120 btw, call Cave Adventurers they have a couple for that price*, or flip the tanks to someone who has DIN and get different bottles.
DIN to Yoke is very annoying, but if you buy the conversion and have the ability to change a tire on your car, you can swap the din back over to yoke in about 5 minutes

 

[Tracy]

Just saying