What Is This Brass Grub Screw?

[MikeAllen]

What is this brass grub screw and what does it do? I removed then replaced the reg 1 air gauge and when I replaced the air bottle it began leaking from here. I noticed it was fairly loose, I snugged it down and the leak disappeared, but I want to know what it does and what I may have affected.

 

[Bigragu]

That is the tunnel path that FX drills out thru one end of the trigger block to the rear. It’s main purpose is to supply the HPA to the regulator behind the trigger, or in your case, level one of regulated HPA to the second reg behind the trigger.

If you look you will see the reg 1 Gage’s thread port is directly tapped perpendicular to that tunnel, so it reads reg 1’s pressure(M3)

You adjust reg two and that pressure now steps down and is read by the rear reg at the rear block

If you remove or peel back the rear upper portion of your hand grip you will see another grub screw plug back there.

Those two grub screw plugs aren’t meant to be touched, ever, but do know it can be a leak source

 

[MikeAllen]

That is the tunnel path that FX drills out thru one end of the trigger block to the rear. It’s main purpose is to supply the HPA to the regulator behind the trigger, or in your case, level one of regulated HPA to the second reg behind the trigger.

If you look you will see the reg 1 Gage’s thread port is directly tapped perpendicular to that tunnel, so it reads reg 1’s pressure(M3)

You adjust reg two and that pressure now steps down and is read by the rear reg at the rear block

If you remove or peel back the rear upper portion of your hand grip you will see another grub screw plug back there.

Those two grub screw plugs aren’t meant to be touched, ever, but do know it can be a leak source

Thanks for the information - I'll need to digest it and determine what made the leak occur and what I've done by tightening the screw. Hopefully more info in the way!

 

[jphef]

There is an oring on the brass screw, if leaking it will need to be replaced. Think it is a 2.2x1 and does not need to be more than snug. Be careful that thing strips in the socket for the wrench easily if you tighten it down too much.

 

[MikeAllen]

And of course I meant to write grub screw but my brain wrote scrub screw!