Re: Re: Re: Re: valve extensions or other remedies


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Posted by Greg Crider on August 17, 2001 at 23:11:50:

In Reply to: Re: Re: Re: valve extensions or other remedies posted by Rick Denney on August 17, 2001 at 09:32:10:

If you'll think about it a bit further, the evenness vs. unevenness of the motion of the valve will depend on how tight the valves are. In other words, the play in the valves will determine how much side-to side motion enters into the valve's travel.

Ideally, pushing the valve straight down will provide perfect travel with the vectors aligned exactly with the valve's axis. However, a significant amount of play in the valves combined with off-center force will still create some uneven forces in the valves that do not fit the ideal model. These should create sticking and uneven wear. The better your valves are to begin with, the more ideal the motions and frictions. More wear, more problems.

Regarding the off center valve stems of some old Conns with short-action valves, pulling the valves on several old horns and looking at wear marks usually shows some uneven wear in the valves. However, this shows up to some extent in all valves, mostly because of the player's finger motions. The tip of the finger does not naturally go perfectly up-and-down; there is a lateral component involved because the natural motion of the fingertip is an arc, not a straight line. Some people tend to push against the valves as they play, and some will pull on the valve tops. No valve is likely to wear perfectly evenly. The question becomes "what part of the wear is because of the player's fingering style, and what part is because of the offset stems?" Who can say without a true statistical analysis? All you can do is come up with a WAG.


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