Hatsan at44-10 5 screw mod failure continued.

[Agedd]

Click image for larger version Name: better than set screws.jpg Views: 0 Size: 95.4 KB ID: 1102Click image for larger version Name: valve two peices.jpg Views: 0 Size: 96.0 KB ID: 1103Click image for larger version Name: valve failure.jpg Views: 0 Size: 100.3 KB ID: 1104

I managed to remove the trigger mechanism and the rear assembly of the hammer tube. That opened it up enough to see what had happened following the valve body failure.
Apparently after valve broke the smaller piece was driven into the hammer with great force. The hammer however was already locked in place by that wishbone shaped lever that is intended to prevent the hammer form rebounding after striking the valve stem. The force on the hammer bent the lever at right angles and could no longer release the hammer and so the it couldn't be cocked. I removed the damaged lever and was able to disassemble the rest of the gun. I repaired the lever and finished cleaning out the debris (set screws, epoxy pieces everywhere).
As you can see in the picture I repaired the valve body with real silver (4.75%) solder but decided not to use it because it's too dangerous. If it fails again and the valve stem gets knocked out it would be like a bomb going off. Instead I see it as a better solution to plugging the 5 holes and the channel for the next valve body.

[rsterne]

In the 2nd photo, you can see that the screw holes are so large that three of them are touching.... That means that one side of the valve was badly compromised.... I would suggest that the screws used were too large in diameter....

Bob

[Agedd]

I used the correct 6 - 32 x 1/16 set screws but you're on to something. My tap was broken so I ground a tapper on the end to simulate the original. Not surprisingly I had difficulty starting the tapping process so I did drill the holes an iota larger. To make things worse I only had my hand drill to do the job and I doubt the holes were in the perfect direction.
From reading your excellent reports it's obvious you have a well equipped shop and machining skills. You also have better computer skill then I do because I couldn't even attach a photo without starting a new thread. That can't be right.
Perhaps I am right though in suggesting us armatures stick to solder or epoxy to fill the holes considering the potential danger.

[rsterne]

Yes, it looks like the holes are not spaced evenly....

Bob

[remtom1200]

My screw mod failed too btw. Just not enough meat between holes to harness the pressure. I made a new valve assembly with only the single hole. I will use cold weld on the next one. It was scary as hell holding the air reservoir with the end broke off full of air. Surprisingly it still held a full 200 bar when unscrewed.