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Discussion of diving methods and equipment available prior to the development of BCDs beyond the horse collar. This forum is dedicated to the pre-1970 diving.
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luis
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Re: USD Royal Mistral (again)

Sat Jan 16, 2016 10:52 pm

Yes, digital caliper is at least as good, if not better.
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Ron
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USD Royal Mistral (again)

Sun Jan 17, 2016 1:29 am

Ach so! The sleeve sits on the orifice, not around it. The orifice with its o-ring goes in first, then the sleeve sits on top of it. The poppet sits in the sleeve, with a spring between it and the crown block. A final spring sits between the crown block and filter.

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Ron
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Re: USD Royal Mistral (again)

Sun Jan 17, 2016 1:34 am

Like so:

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luis
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Re: USD Royal Mistral (again)

Sun Jan 17, 2016 7:24 am

slonda828 wrote:Ach so! The sleeve sits on the orifice, not around it. The orifice with its o-ring goes in first, then the sleeve sits on top of it. The poppet sits in the sleeve, with a spring between it and the crown block. A final spring sits between the crown block and filter.
Yes, that makes more sense. That is what I expected.

The O-ring is designed to seal directly with the body.

The length of the sleeve matches the dimension for the (balance chamber) supporting edge on the other balanced regulators (RAM, Conshelf, etc.).

Thanks
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Herman
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Re: USD Royal Mistral (again)

Sun Jan 17, 2016 8:34 am

No wonder the thing didn't work, it's metric !!
Sorry, just had to say that. :)

Ron you need to remeasure the diameter of the body (12.41) , it can't be less than the diameter of the orifice (12 .590), the orifice would not go inside . Nor would the sleeve at 12.6 Based on other regs, It should measure about 12.7mm . Sorry, the machinist in me coming out.
Also, please measure the thickness of the orifice and the total depth of the body, top edge to the bottom (where the bottom of the orifice would rest)- it should be about 26.4mm .

I will have to admit, you guys have me wanting to try my hand at making one of these things.... just what I need, another project. :)
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antique diver
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Re: USD Royal Mistral (again)

Sun Jan 17, 2016 10:34 am

Makes more sense now that we know how it's assembled. I think a good starting place is to build a new orifice with some modern material. The other parts shouldn't present much of a problem. If I had better machining skills I would be tempted to try modifying an old Mistral body, and would try to use a crown block with a backup ring. That one particular original item may have caused some of the original problems that made this reg cantankerous.

I might try it anyway if I find a Mistral with a damaged orifice.

Herman, you should tackle this! I have an original metal poppet available if you or Ron need it, but no other parts for this reg.
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Herman
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Re: USD Royal Mistral (again)

Sun Jan 17, 2016 10:47 am

What is scaring me is I have several ideas on how to proceed......I may take you up on the hard seat.....and if anyone has dead mistral bodies, I am interested in them...doesn't matter what is wrong with them.
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Re: USD Royal Mistral (again)

Sun Jan 17, 2016 11:56 am

Herman wrote:What is scaring me is I have several ideas on how to proceed......I may take you up on the hard seat.....and if anyone has dead mistral bodies, I am interested in them...doesn't matter what is wrong with them.
email sent
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Re: USD Royal Mistral (again)

Sun Jan 17, 2016 5:25 pm

More measurements gents. I will add that the measurements of the depth of the body are to the shelf where the orifice rests, and not to be space behind it. I have attached another shot of the inside of the body for clarification.

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Ron
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USD Royal Mistral (again)

Sun Jan 17, 2016 5:26 pm

If you have any tips for how to measure better, by the way, then I am all ears. I have no formal training in precision measurements or machining or anything of the sort, so I will be receptive if you tell me what you need and explain it, like Herman did :)

I am also willing to provide materials or monetary support for this endeavor. All I ask is that I get enough parts to keep my RM running. A balanced single stage regulator has been a pipe dream of mine for a long time. If we can create something that Bryan can sell to convert or revitalize the RM or a faux RM then my hope is that we can provide him with a product to sell in the store.


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luis
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Re: USD Royal Mistral (again)

Sun Jan 17, 2016 9:40 pm

I have a complete design for a working balanced single stage regulator, including the mechanical and fabrication drawings and a couple of working prototypes. I have done extensive testing with the prototypes and consider them a relatively mature design, not just an idea.

My design includes high pressure ports and it uses many off-the-shelf parts. The final touch is a lever system with adjustable mechanical advantage to drop the cracking effort down to a range close to a two stage regulator.

I offered the design to Bryan, but he did not see much of a market potential for a balanced single stage. I tend to agree with him, but maybe you will change his mind.

There is a very small number of Royal Mistrals. IMO it would be very hard to sell enough part to make the investment worthwhile, but Bryan would have to answer that.
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Bryan
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Re: USD Royal Mistral (again)

Mon Jan 18, 2016 10:45 am

>I offered the design to Bryan, but he did not see much of a market potential for a balanced single stage. I tend to agree with him, but maybe you will change his mind.<br /><br />There is a very small number of Royal Mistrals. IMO it would be very hard to sell enough part to make the investment worthwhile, but Bryan would have to answer that.

Negative Ghostrider....The pattern is full............

Now before you spill coffee or start up a game of sand volleyball with a bunch of oily bohunks give me time to explain in detail.

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ScubaLawyer
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Re: USD Royal Mistral (again)

Mon Jan 18, 2016 12:19 pm

Bryan wrote:
Now before you spill coffee or start up a game of sand volleyball with a bunch of oily bohunks give me time to explain it.
"oily bohunk" - wow. I'm starting to see Bryan in a whole new light what with use of linguistic paradigm vis a vis Top Gun and 16 Candles. Although indirect reference to any Molly Ringwald movie is somewhat disturbing on a molecular level. I love it! :lol:
"The diver who collects specimens of underwater life has fun and becomes a keen underwater observer. .. seek slow-moving or attached organisms such as corals, starfish, or shelled creatures." (Golden Guide to Scuba Diving, 1968) :D

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Bryan
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Re: USD Royal Mistral (again)

Mon Jan 18, 2016 5:12 pm

I really hope we can keep the conversation going on how the Royal Mistrals of the world can be made to function reliably.
I'll make a new post to discuss the pros and cons of a new Single Stage regulator.

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Ron
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Re: USD Royal Mistral (again)

Mon Jan 18, 2016 6:06 pm

I know we can figure something out together. My main concern is can we get enough seats working without having to hand make each one? I'm sick of hand making seats and stuff. I did that with the tilt valve regulators and the original calypso and whatnot.


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