Weird Frontweights

[Ron Nossaman]

>I assume you're talking about distortions of DWs due to friction.

Yes, since the weigh off and individual key leading is done after action
assembly and is intended to even up DW.



>If in fact that kind of troubleshooting is part of that factory's 
>assembly schedule. More likely, not. So the choice of leading (either 
>fixed pattern, or individually set FWs) is irrelevant. 

No, the leading choice isn't irrelevant, at least not when the individual
leading is done at the end of the assembly process. Done at the beginning
like pattern leading, individual leading would yield the better job, then
the regulator would have to make the action "work" by means other than
positioning leads. As you say, it probably doesn't get done, but the
pattern leaded action will be easier to repair and regulate after delivery
than the individually leaded. It's easier to repin a flange than to
(re)move a key lead. If the action parts are uniform enough at assembly,
the leading methods should be pretty much interchangeable.  


>With a pattern 
>leading, at least that portion of the lever train's inertia coming 
>from the leading will be held uniform (regardless of what kind of 
>mess may be sitting on top of the capstans). DW/UW will be reflective 
>the wide range of friction, leverage ratio and hammer weight from 
>note to note. With individually leaded keys (set for DW not BW, mind 
>you) the static measurement of DW will look good, but inertia will be 
>even more cock-eyed from note to note.

Yep, and as the friction changes in the action through wear or technical
intervention, the DW will also change, though nothing has been done to the
leads. Then when someone comes along to get it working again and measures
FW, they find these wild differences from key to key.


>>That's why pattern leading is a better idea. It's a known weighting
>>progression, and it helps to have SOMETHING reasonably dependable to work
>>from.
>
>I agree that it does a much better job of holding overall inertia so 
>a reasonable level of eveness than individual leading for DW. Inertia 
>is a far more critical quality to a pianist than simple DW.

I agree, until the action loosens up enough for the DW differences to
become annoying. Pattern leading produces actions that should tend to age
more uniformly, at least in feel.


Ron N