Needle PackingScrew Set Fall Out!!!

[Than]

I use iwata hp-cs. After cleaning paintcup I dissemble my airbrush. While I pulling trigger, the needle packingscrew set fall out. I'm sure that it's tight enough before use. How did it come out?

 

[DaveG]

only one way for a screw to come out, right? It has to be unscrewed. The action of the needle sliding in and out through the teflon seal could cause torsional rotation - the unscrewing of the screw - but, not if it was actually tight enough to begin with. When tight enough, the screw forces the teflon to contact the front of the cup, compressing the teflon a small amount in order to seal against the needle. This compression puts tension on the threads, which would prevent it from turning on it's own...

 

[Mr.Micron]

Also I have found that is you use cleaning brushes or q-tips to clean in the area the needle bearing seal is; That is can loosen the screw as well.