<html> At 05:10 PM 04/05/2001 -0700, you wrote: <blockquote type=cite cite>I must get in here!  I haven't been hampered by a formal education, but I have been exposed to alot of this technical stuff. Please excuse my lack of understanding of the finer points of inertia and my use of made up terminology. Let me hypothesize that an infinite weight applied to an infinitely small radius, would have no inertia in the rotational mode but have lotsa inertia in the horizontal mode.  Vertical mode would introduce gravity and confuse the issue.  ( we all know that there is no such thing as gravity.  The earth sucks.) Now, since more weight closer to the balance rail will still give the same dw/uw the inertia will be less due to the radius of the weight. Now, someone said that the smoothness of the uw/dw is affected.  Let me suggest that the friction is increased due to the dead weight of the increased weight closer to the balance rail pin.  Now the rotational movement of the key is restricted due to the additional weight, resulting in erratic dw/uw measurement.  Additional (dead weight) at the balance rail will compress the balance rail felt punching and add up/dw due to the added weight. Now, my question is:  Is that why the patent for the accelerated action includes the round surface of the balance rail to compensate for the increased weight of the lead in the keys nearer to the balance rail. I haven't read the patent so I might be out in left field. I believe someone said that S&S doesn't use this anymore.  Would that be because the price of lead went up or it wasn't such a good idea anyway or nobody appreciates or understands it? I don't have a clue.??????? Carl Meyer</blockquote> From what I have observed, the balance rail bearing maintains the fulcrum close to the pin. If you scrutinize the movement of the key on a flat punching, you may notice that the key pivots from the back of the punching to the front; an increasing KR as the key depresses. Jon Page As for the other stuff, re-read this: ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ To: <pianotech@ptg.org> Subject: Re: Keylead inertia and leverage (was Re: Ideal leading pattern:) Ric, This is one of those counterintuitive concepts:  how can more weight result in less inertia?  The key (no pun intended) is in the leverage.  The closer the weight is to the balance rail, the shorter the distance it moves during a keystroke.  Less acceleration.  The closer the weight is to the balance rail, the more leverage is available to the pianist to overcome the inertial resistance.  These two leverage effects (less acceleration, more mechanical advantage) combine to cause less resistance to be felt by the pianist.  If you can struggle through the math of my earlier post, I think you'll see how it all works out. Mike </html>