Scubapro chrome plated brass regulators...

[Umuntu]

My apologies if I am in over my head here...

Try this link:

McMaster-Carr

Or here for button head screws:

McMaster-Carr

Scroll down a bit to see brass M3 x 0.5mm screws in different lengths [5-20mm] on either link.

I hope that helps!

Thanks. I really like McMaster Carr, particularly their ordering system. Although a few years ago they refused to ship abroad to me. Something about US export controls.

They don't have brass screws with a head 4mm or less. I would have to get 18-8 stainless, which is not salt water corrosion resistant. I may have to resort to @axxel57 's solution of reducing the head size.

Also their metric screws are considerably more expensive than the imperial equivalent, and hex screws in both are understandably much more expensive than slotted screws.

 

[Andrew Dawson]

Thanks. I really like McMaster Carr, particularly their ordering system. Although a few years ago they refused to ship abroad to me. Something about US export controls.

They don't have brass screws with a head 4mm or less. I would have to get 18-8 stainless, which is not salt water corrosion resistant. I may have to resort to @axxel57 's solution of reducing the head size.

Also their metric screws are considerably more expensive than the imperial equivalent, and hex screws in both are understandably much more expensive than slotted screws.

Bummer, well, if you find something on there you like and need me to ship to you, just let me know, I will see what I can do to help

 

[Angelo Farina]

My apologies if I am in over my head here...

Try this link:

McMaster-Carr

Or here for button head screws:

McMaster-Carr

Scroll down a bit to see brass M3 x 0.5mm screws in different lengths [5-20mm] on either link.

I hope that helps!

Those are DIN 912, so standard head. Approximately 5.5 mm diameter, instead of the 4mm diameter required for fitting on the head hole. here the table with the geometry of screws compliant with DIN 912:

These inox screws are easily found on Amazon, but they do not fit the ring of Scubapro brass regs...
https://www.amazon.it/50-pezzi-cilindrica-esagono-incassato-912-Acciaio/dp/B01IMGYTFK

 

[Angelo Farina]

Here’s what I use fits perfectly... so you think American made?
View attachment 580287

I was meaning the reg where Imperial screws are used should be built in the US. At least here is what I understood, having purchased 6 109s in Europe, and all have M3 screws, and two in the US (one 109, one 156), and they have Imperial screws.

 

[Open Ocean Diver]

Must be American made then 3/32, I did buy it here in the US.

 

[Angelo Farina]

Must be American made then 3/32, I did buy it here in the US.

The screw of American 109s is labelled as "4-40". For understanding what it means, read the article below. And then tell me if going Metric wouldn't be a sensible choice also in US....

Without Metric Threads We’re Screwed | The Metric Maven

 

[Open Ocean Diver]

I know I know I live here in Canada so I use the metric system more than ever and boy does simplify things. Thanks for the link was a cool read.

 

[saxman242]

The screw of American 109s is labelled as "4-40". For understanding what it means, read the article below. And then tell me if going Metric wouldn't be a sensible choice also in US....

Without Metric Threads We’re Screwed | The Metric Maven

Interestingly, metric screws tend to have much larger heads on them than imperial. I've had several designs I have worked where it was necessary to use a imperial fastener rather than metric for head clearance when using commercial off the shelf fasteners.

 

[lowwall]

The second stage above looks much like the very first regulator I ever dove. It belonged to my roommate in the early 1970ies. Yes, this one is fancied up a bit, but it's still an AMF Voit Swimaster.

Venturi & Bernoulli are up there somewhere smiling.

You dove the original MR12 which was introduced in 1970. The bypass tube was added in 1977 on the MR12 II. There's more info on the Voit regs on this post from my Mares regs thread.

And yes, the same design that began with the MR12 II is still in production today as the Mares Abyss Navy and Mares XR.

 

[Rusty Shackleford]

I wonder if you could take the 18-8 screws and give them a little extra passivation?