Long yoke?

[Ron]

Yell at me later, because I know it's on here, but I couldn't find it. I know that in order to use my SPG with a banjo fitting I need a longer yoke on my mistral. I also know that service pressure on my current yoke (and the one on my Conshelf VI) are only 3000 PSI max (for a 2250 working pressure). Which yoke is a good one to add to facilitate adding a banjo fitting and also using higher psi tanks like we may have to for SD?

[usddude]

I'm not sure by what you mean by "higher psi tanks for SD"

[Fibber McGee]

2250 to 2400 should be about all the pressure you should be using in the usual 72's. Even more so with a Mistral since it will breathe easier at lower pressures anyway. (And, unlike the Phoenix/Conshelf/etc., its high pressure seat may not be happy with much more than that anyway.)

As for the long yoke, the VDH store has one that will fit all of the USD 2 stage regs, but I do not know if it will also match the Mistral's attachment point....so I would defer that one to Bryan.

What I have been doing for now is to put an SPG on the high pressure port of the tank's valve. (my 72 has a Dacor K valve with an HP port that is downstream of the shutoff so it works fine) At some point I will get a good J valve on there and go that route for my older setup.

[Ron]

I'm just trying to plan ahead if I manage to scrape enough money together for the next Sand Dog in the bahamas. I need some way to tell how much air I have left in my tank. There's no guarantee that the tanks we will get will all have working j valves, so I need a way to hook my SPG up and stlil use my mistral. If I use the actual connection on the valve itself, I'm going to have to change my SPG every time I change tanks. I guess I'm just trying to plan ahead. For around here I'm going to get a J valve.

[Fibber McGee]

Yes, the spg on the tank is not ideal...especially if you are traveling since you can't always get the tank/valve combo you want....if the long yoke on the VDH store site won't fit the mistral, perhaps another long yoke can be modified to fit? or one custom made ...seems like basic machining for the most part.....if you know someone with a milling machine who needs a winter project you are set.

[Nemrod]

The standard long yoke is adequate for the 3,000 psi tanks.

By "higher pressure" he is referring to 3,000 psi vs our typical 2250 plus 10% 72s etc.

The standard long yoke will serve you well, true, it is a little on the light side but several of us have used them for years on 3,000 psi tanks and at least one engineer we all know has done an analysis.

Does that answer the question?

Nem

[Fibber McGee]

I think part of his question is which long yoke would fit the Mistral...I do not know if the one in the store that fits the 2 stage models will work or not(??) ...my guess is it would, but I'd hate to tell someone wrong.

[luis]

Here are some dimensions I took:

Mistral
Nut OD: 0.935”
Yoke ID: 0.977”

DA Aqua Master
Nozzle OD: 0.866”
DA yoke ID: 0.9”

The yoke form the Mistral and the DA Aqua Master are not interchangeable.

A DA Aqua Master yoke will not fit a Mistral, but it can be machined to enlarge the opening to fit.


Just for general knowledge:

The Mistral yoke is too large for a DA.
I tried a Mistral yoke on a DA nozzle and it has too much play. Even if it wasn’t a problem structurally (which I am not sure about that) the yoke may not provide even pressure to the O-ring connection. I would think that the chances of blowing an O-ring would be fairly high.

[Bryan]

Below is from a conversation Luis I and a few others were having on Sunday.....More info will follow by the end of the week on this subject........There will be no 2250 cylinders or J valves in the Bahamas unless folks bring them in themselves....Everything will be 3000psi K valve. No problem for any Mistral in my opinion...

I tried a Mistral yoke on a DA nozzle and it has too much play. Even if it wasn't a problem structurally (which I am not sure about that) the yoke may not provide even pressure to the O-ring connection. I would think that the chances of blowing an O-ring would be fairly high.

Here are the dimensions I took:

Mistral
Nut OD: 0.935"
Yoke ID: 0.977"

DA Aqua Master
Nozzle OD: 0.866
Nozzle hex dimension across the flats: 1 inch
Nozzle hex max dimension across the rounded corners: 1.098

[Fibber McGee]

Thanks Luis...I was thinking of doing something similar so that is good information to have....looks to me like it would be very simple to buy a long yoke for the DA and bore the hole to fit the Mistral. (making sure it is straight, true, and not oversized, of course)

[Nemrod]

My Mistral has a long yoke which I took from a dead Calypso (not J) circa 66 or so. I use a banjo with it.



Nem

[Ron]

Ok, since we know we are going to be using K valves and 3000psi tanks (which you guys said were fine with the standard yoke) I need to find a way to get a longer yoke for my mistral if I want to use a SPG (which I do if we're using K valves). Nem, you said the yoke from a USD calypso works? IIRC the only difference between the calypso and the conshelf is in the first stage guts. I think the yokes even have the same part number...

[Bryan]

Below is from a conversation Luis I and a few others were having on Sunday.....More info will follow by the end of the week on this subject........There will be no 2250 cylinders or J valves in the Bahamas unless folks bring them in themselves....Everything will be 3000psi K valve. No problem for any Mistral in my opinion...

I tried a Mistral yoke on a DA nozzle and it has too much play. Even if it wasn't a problem structurally (which I am not sure about that) the yoke may not provide even pressure to the O-ring connection. I would think that the chances of blowing an O-ring would be fairly high.

Here are the dimensions I took:

Mistral
Nut OD: 0.935"
Yoke ID: 0.977"

DA Aqua Master
Nozzle OD: 0.866
Nozzle hex dimension across the flats: 1 inch
Nozzle hex max dimension across the rounded corners: 1.098

[Nemrod]

I am not sure if a 66 Calypso had the same yoke as the Conshelf of that era, I just don't know. The yoke I have is not relieved on the bottom. It fits my Mistral nicely with about normal play. I really hate to take it apart and get measurements because I just put it together a few weeks ago.

The red letters in the post by Bryan, read it, it means something. If after the end of the week you still need my Mistral measurements I will get them to you. So, chill.

Nem

[captain]

I am not sure if a 66 Calypso had the same yoke as the Conshelf of that era, I just don't know. The yoke I have is not relieved on the bottom. It fits my Mistral nicely with about normal play. I really hate to take it apart and get measurements because I just put it together a few weeks ago.

The red letters in the post by Bryan, read it, it means something. If after the end of the week you still need my Mistral measurements I will get them to you. So, chill.

Nem

I compared my Conshelf VI yoke to the long yoke on my Mistral and they appear to be identical. The only difference I could see is the retaining nut is a hair longer on the Mistral.