Cressi SL trigger screw and pin

[Crispin]

Namely the one above. I'm in the process of chopping down my SL 100 to an 85, because once it has a vacuum kit on it, I just don't need the extra length, it's also easier to load and handle for me.

Now when I bought my tovarich kit from Ramon, I got a replacement one of these screws and a 1.5mm pin instead of the 3mm. It made the gun so much nicer to use, so I want to do the same for this gun.

Ramon isn't with us any more, so I need to find another way to do this. I can either make the screw and pin myself, or if anyone has any ideas on where I might source such a thing then I'd appreciate your input. Thanks guys.
Crispin.

 

[popgun pete]

Have a look around for conversion kits as there are some available, for example the original "Cyrano" had an insert and the same could be done for other models.

 

[Diving Gecko]

Edosub.it sells them for about 20E as far as I remember. Just not 100% if Cressi use the same thread in that bushing as Mares and Seac but he would know.
Changing from a 3mm pin to a 1.5mm pin, you need to incorporate an extra o-ring and some of the parts get really small. I have made some of these myself now but I also have a hobby lathe. It wouldn't be easy to do without it and for E20 from a shop, it might not be with trying to DIY.

 

[popgun pete]

It is a query that has come up before, but right now I cannot find the reference, however a search in Italian might locate it as you are surely not the first to ask. Going purely on memory the first “Cyrano" has a bush that fits in the 3 mm hole to convert to the 1.5 mm trigger connection pin or trigger transmission pin. That adds an extra "O" ring to seal the combination and the whole lot is sealed on the gun by the screw threaded disc bottoming flush on the female threaded plastic well in the rear grip handle.

People forget that when the "Cyrano” first appeared it had a fat trigger transmission pin and only the “Apnea System” version was fitted with a 1.5 mm diameter pin. Then after a number of years Mares only made the 1.5 mm trigger pin version and suggested that any guns needing new handle parts should be upgraded to the 1.5 mm pin equipped handle. That is why there is an adapter in all those later “Cyrano” guns.

 

[Diving Gecko]

Yeah, I don't think Mares on anyone else changed the size of the bushing when they went to 1.5mm threads, so this is how they are made (haven't bothered to check the Evo handle). One internal small o-ring inside the threaded bushing to seal the 1.5mm to the inside walls of the threaded bushing and then the top part of the bushing assemblye which is often a 3-3.5mm tube seals against the seat in the handle using the same size o-ring as the original 3mm pin.

Here's one of my homemade ones - with proof of my obsession with double o-rings whenever possible:

I can't recall the exact dimensions but the bigger green o-ring would be close to what a ø3mm pin would normally use. I think the two smaller o-rings might be 4.5mm x 1.5mm (OD x W)

 

[Diving Gecko]

Oh, I did one for my Predathor, too though the Predathor 2mm pin is already substantially smaller then the older 3mm standard but the pics do an alright job at showing the differences (original on the left):

 

[popgun pete]

Here is the "Cyrano" patent and parts diagram detail. The 1.5 mm pin adapter is part 51. Now I look at it again after some years since last seeing it I think Mares used only one "O" ring to do two jobs, i.e. seal both the pin and the base of the bush adapter.

 

[popgun pete]

The upshot of this is you might try the Mares adapter in your Cressi SL gun. Now I think that Mares sold these as the complete grip handle, but you may be able to recover one from a junked gun as those parts don't wear out.

 

[Zahar]

Why bore?

 

[Diving Gecko]

Why bore?

To give more support to the thin trigger pin.
(If you are asking about what looks like a small hole then it's just a shadow, not a hole).


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[Diving Gecko]

Here is the "Cyrano" patent and parts diagram detail. The 1.5 mm pin adapter is part 51. Now I look at it again after some years since last seeing it I think Mares used only one "O" ring to do two jobs, i.e. seal both the pin and the base of the bush adapter.
View attachment 53470

I am not really getting this diagram. Or rather, I can't see how the trigger would not leak in that design. The o-ring only seals the pin against the inside of the bushing. It looks to me like there's still a leak path between the plastic and the bushing e.g. along the threads. I guess it could possibly seal if the the bushing is screwed in really, really tight but then you run the risk of stripping the thread in the handle.

If you designed the handle from scratch, you could certainly make it work with one o-ring only but you would need to make the bore (o-ring seat) smaller so you can run a smaller o-ring. A bore around 3.8-4.0mm would work with a 4.5mm x 1.5mm (OD x W) o-ring. But I have a feeling the Mares designers kept the original bore size from the times of the bigger pin and hence they needed to use the trigger design with two o-rings.

[EDIT] I notice now that it is a patent diagram so perhaps not everything is correct in it? Maybe the trigger doesn't look like that in the production Cyrano.
[EDIT_2] Looking more closely at the right hand exploded diagram it might have an o-ring on the adapter but it's hard to tell as the resolution is a bit low. But it would sense if it did have one.

 

[popgun pete]

That is what I thought the first time that I took a “Cyrano” apart, but the threaded disc or bush seals up against the plastic at the bottom of the well. Scratch the surface there and you will ruin the handle, although the situation might be retrieved with a thin rubber washer. The sealing mechanism at that location is analogous to how the inlet valve housing seals in the rear of the plastic handle as no "O" ring there either.

In earlier guns the metal disc just sandwiched the "O" ring sealing both on the trigger transmission pin and the surface of the well in the handle.

 

[Diving Gecko]

That is what I thought the first time that I took a “Cyrano” apart, but the threaded disc or bush seals up against the plastic at the bottom of the well. Scratch the surface there and you will ruin the handle, although the situation might be retrieved with a thin rubber washer. The sealing mechanism at that location is analogous to how the inlet valve housing seals in the rear of the plastic handle as no "O" ring there either.

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[Diving Gecko]

Yeah, I thought about the inlet valve too. But that one you can tighten to your heart's content since it screws into an alu barrel.
But interesting - I'll take the trigger bushing out of the Evo handle after this trip and see how they did that one.


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[Zahar]

To give more support to the thin trigger pin.
(If you are asking about what looks like a small hole then it's just a shadow, not a hole).


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shadow,

 

[popgun pete]

shadow,

More a reflection, look at the other one, black mark is more pointy, but lighting effect "rounds" off the same mark on the right hand image.

 

[popgun pete]

Drawn from memory, but the principle is shown, only sizes are approximate and not to scale.

 

[Crispin]

The only place on the the internet where an "obscure question" like this would turn into a trove of information, this group is fantastic for this, thank you guys.

I am going to move it to 1.5mm when the gun is done, just because it made such a difference in the 70 I have.

@Diving Gecko, where do you get your parts from, o rings and stainless pins in particular?

I'll see if I can find a mares but here in NZ there are no pneumatics really....

 

[Crispin]

Oh forgot to ask what is the thread pitch of the main screw please?

 

[popgun pete]

Edosub is the place to look, as for the thread size on the disc or bush that traps the "O" ring I never bothered to measure it, but DG will know. All my pneumatic guns bar the Mirage are under pressure, so I cannot check it. My Cressi guns are similarly under pressure as we are in the diving season, but 44 Celsius temperatures for the last couple of days and I am staying out of the heat. Being boiled alive in my wetsuit struggling to make it into the water is something I have done in the past, but not now. Blast furnace conditions are no place to suit up in!

https://www.edosub.it/
https://www.edosub.it/ecommerce/ind...mart&page=shop.browse&category_id=57&Itemid=1