[CAUT] fulcrum of a key

[Ron Nossaman]

Don Mannino wrote:
> The 1/2-round changes the way the key rolls, but I believe it actually
> reduces the amount of fore-aft movement of the pivot line as compared to
> a normal rail.  

It most certainly does. You can see the difference in action 
models.


>It is my feeling that it reduces the ratio change as
> compared to a normal rail, and that may be why it was adopted in the
> first place!  

That's my suspicion.


> It seems that David Stanwood's nifty idea does force the rotational axis
> to become more stationary, although it seems there are other drawbacks
> to the system, such as increasing the vertical movement of the key on
> the pin.  This is not a desirable motion to have, although it is
> probably OK as a trade-off for improving the touch in other ways.  The
> amount of up-down sliding must be pretty minimal, even at the most
> extreme settings.

Not a lot, if at all more than in flat punching systems, I'd 
think.
Ron N