Posted by Jim Andrada on June 02, 2002 at 21:00:09:
In Reply to: Re: Re: Re: Re: Re: Re: Re: Swedging Your Rotors posted by Rick Denney on June 02, 2002 at 08:12:22:
Rick,
Thanks for your comments. My recollections were from quite a long time ago and I wasn't sure they still had any "bearing" on the subject. (Pun intended)
Yes, as I think back it was exactly the precession issue I was thinking of.
However, I'm also not quite sure if 90 degrees of rotation might be "enough" to minimize the problem - I guess it depends on the diameter of the bearings themselves.
I think the oilite bronze is wonderful stuff, but I've also been wondering about teflon impregnation. We use a teflon impregnated sheet metal in some of our tape applications where there is significant exposure to sliding contact.
I guess the other thing to think about is what kind of duty cycle a tuba valve should be designed for.
Probably each valve gets cycled a few hundred times a day in a high use (professional) environment - say mabe 5k cycles per week or a couple of hundred k cycles per year if really used a lot so a ten year or longer life would be on the order of a couple of million cycles. And maybe 1st valve is most active so maybe an "engineered" tuba would have a larger diameter bearing on the first valve.
Maybe we can get a thread going on what am "engineered" tuba would be like - I'll post a note with this subject line.