Doubles manifold leak

[Gone for diving]

Yep there is your problem

 

[MaxE]

You have pictures?

 

[Gone for diving]

How handy are you? What's you shop tool collection like?

 

[MaxE]

Yep there is your problem

What are you seeing?

 

[MaxE]

How handy are you? What's you shop tool collection like?

I consider myself handy. I could
Probably build a house with the tools I have but it’s not a machine shop. I tend to not shy away from an excuse to buy a tool

 

[Gone for diving]

The hole is to small for the regulator center nipple,
If you have a vernier measure it and double check.
But just by the picture it's small

 

[MaxE]

Yep there is your problem

Ok but what do all of my other reg sets seal fine and why to both sides of the manifold have an issue with this one reg?

 

[Gone for diving]

This reg has a larger diameter than your other regs.

You manifold is machined the same in each din hole.

 

[MaxE]

I’ll get the calipers out and confirm, this in line with my thinking as well but wanted to talk it through before I order a new DIN nipple

 

[Gone for diving]

You have a few options.
Simplest is get a new din end for the regulator.

Next best is remove the valves,
Remove the valve guts.
Clamp and jig properly.
Center and drill the center hole open.
And finish with an end mill....

Or machine the end of the DIN smaller in diameter. But you will need a lathe, and don't know if you have enough metal to do that....