Posted by Klaus on August 17, 2001 at 17:18:52:
In Reply to: Re: Re: Re: valve extensions or other remedies posted by Rick Denney on August 17, 2001 at 09:32:10:
I am no engineer, as I found the education on our tech university quite boring (still I achieved so much, that I could work as an assistant in teaching the old days paper equivalent of present days Computer Aided Design. Basically bringing virtual 3D objects down on a 2D paper form).
And I happen to be so reassured of my understanding of classical theories of mechanics, that I find that you are preaching a non-kosher statement in one certain matter:
We do agree, that off-center valve buttons have to be attached to the stem/piston in a way, that establishes a stiff system.
Now we enter an area where my English tech vocabulary has its strong limitations. But I will maintain the view, that if an off-center valve button should be applied at all, then because the contact point of the finger (representing the acting force) necessarily means an application of a force off-center to the axis of the piston movement.
In that light the off-center valve button will act as a fixed, non-hinged lever arm. By definition transmitting powers in a way, that will try to tilt the piston. Hence causing bilateral forces, that will cause excessive wear on the "finger-touch-point" side in the upper half of the piston casing. And excessive wear in the opposite side of the bottom half of the piston casing.
And this no matter how straight the finger movement is done.
This is not intended to be an argumentation by me against the very "off-set-valve-button" idea. Only I want to arise some awareness about the fact, that the needs for valve rebuildings will come up after some years. A technical operation that might cost som $$$. But which still is greatly to be preferred to a hand rebuilding or even to the transplant of a donor hand.
Klaus