Tuning Huma Regulator Rebuild Questions

[Bugman]

Hi all: Yet another thread on my Marauder .177 rebuild. I tore it down since the regulator no longer worked and I have a couple questions. I have replacement parts on order. 

On the picture below, what would cause the disk to break as I assume it wasn't made this way?

Second question. Does the belleville spring layout make sense for a low power operation? I want around 1500 PSI for a high shot count, quiet, low FPS tune (715 or so). 

Thirdly (promise is the last...). To avoid any fatigue question on the belleville springs, would you take two of the 4 flat washers out and exchange them for the 2 up front and replace back in the 4 washers stack? My guess would be the two on the left in the photo were under more stress. I also read elsewhere that these should basically last forever, so curious if that is any consideration once I get this put back together. 

Thanks.

 

[FuzzyGrub]

If you are talking about the "bite" out of the white disk, that is normal. The rebuild kit will look the same. It does look like it has a deep imprint where the spool seals. Flip it over and use the other side.

I don't know about the stack, but huma has always answered my technical questions in a timely manor.

 

[Motorhead]

Yes Flip the disk over ...



Now here is perhaps a lesson or "Case in Point" on the seat making such an heavy DENT into the seal material * Generally this is what happens when there is NOT A GRUB SCREW in the adjustment bonnet air bleed hole. The regulators spool cycles very quickly w/o the screw in place and reg doses recover faster, but at a cost to beating the seat to death and creating a slowly but ever changing set point until such time seat NO LONGER seals as it should.

The grub screw is a FLOW DAMPER that slows down the motion and recycle speed so seat is not pounded on.

If said regulator had said grub screw in place I would honestly be shocked !



Scott S

 

[biohazardman]

You can usually just flip the disc over. That could be the reason the reg does not function. I don't have a Marauder so cant help you with the order of the spring washers but you don't want to mess with it if it is stock as it is probably right where you want it to be. Motorhead has more info for you.

 

[Bugman]

Yes Flip the disk over ...



Now here is perhaps a lesson or "Case in Point" on the seat making such an heavy DENT into the seal material * Generally this is what happens when there is NOT A GRUB SCREW in the adjustment bonnet air bleed hole. The regulators spool cycles very quickly w/o the screw in place and reg doses recover faster, but at a cost to beating the seat to death and creating a slowly but ever changing set point until such time seat NO LONGER seals as it should.

The grub screw is a FLOW DAMPER that slows down the motion and recycle speed so seat is not pounded on.

If said regulator had said grub screw in place I would honestly be shocked !



Scott S

Scott: Are you referring to the M3 screw on top of the set screw on the Huma reg? If so, in my case it was in place but was a well used 5 year old rifle. Not too surprising.

 

[Motorhead]

Color me surprised ... having serviced dozens and dozens of Huma's I generally see the o-rings harden up & fail before seat gets anywhere that beat down.