Pinning and Tone

[fssturm@unm.edu]

   There are two things being said in this discussion. One is that there can be a 
perceived loss of power on repetition with high check, due to how close the 
hammer is to the string at the moment when the jack is re-engaged. I've never 
heard that complaint myself, but  I'm sure it's within the realm of possibility, and 
Ed Foote confirms that he has had such a response from a performer. (The 
performer has the option of altering his/her technique, allowing the key to rise a 
bit more, and will then get the same power. And the key would have risen the 
same as it would have to rise were the check lower - or at least fairly close. But 
by all means we should meet the performer's desires if possible.). 
   The other observation has to do with geometry of tail versus check. Certainly 
at the limits of high checking, there will be a point at which there will be drag on 
a hard blow. But that point will vary depending on the geometry involved. If you 
have optimum geometry, you can get 3/8" check without having the drag 
problem - I'm convinced of this through experience. What exactly is that 
geometry - or are there a few variations?
   Roger Jolly tells me that 2 1/2" radius on the tail, together with something like 
70 degrees for the check is optimum. And Roger is usually right about this sort 
of thing (except for the rare instances when he is wrong <g>). Steinway is using 
68 degrees for the check, which keeps the top of the check away from the tail a 
bit longer, or so I picture it to myself. However, when I was told the radius was 4 
1/2", I thought that would mean the bottom portion of the tail would tend to graze 
on the way up, and would dig in on the way down, rather than creating a good 
friction bond. Hence my hypothesis that perhaps they do machine to a radius of 
4 1/2", but from a point above the shank (which would kind of give you the same 
angle at the bottom of the tail as a far shorter radius from a point on the shank, 
and might actually give better clearance on the way up).
   In general, according to my understanding, a smaller radius on the tail and a 
more acute angle for the check will yield higher checking without drag. But at 
some point that falls apart, because the check and tail are at less and less 
optimum mating angle when they come together on rebound.
   Does all this make sense, or am I off on a shaky limb here? And is an arc of a 
circle the optimum shape for a tail, or is there a variant that would work better? (I 
am thinking of a mild parabolic curve - starts like a circle segment, but the curve 
gets steeper). Or is what I have suggested Steinway may be doing another 
wrinkle that works?

Regards,
Fred Sturm
University of New Mexico

Quoting Jim Busby <jim_busby@byu.edu>:

> List
>  
> I need to clarify that Richard Davenport says it engages slightly
> when
> the backcheck is close (high checking) on hard blows. As I understand
> it
> if it is regulated that close the tail may skim the surface on a
> hard
> blow because of shank flex. Could be. I'd like to see his
> presentation
> and those films.
>  
> Thanks,
> Jim Busby BYU
>  
> -----Original Message-----
> From: caut-bounces@ptg.org [mailto:caut-bounces@ptg.org] On Behalf
> Of
> Jim Busby
> Sent: Tuesday, October 28, 2003 4:57 PM
> To: College and University Technicians
> Subject: RE: Pinning and Tone
>  
> Alan,
>  
> According to Richard Davenport the backcheck does slightly involve
> the
> tail if you look at those high speed tapes of it. I'd like to see
> it,
> but he says that higher checking does result in less power as
> Richard
> said, and Ric. clarified for me.  As Ric said, more drop = slower
> rep,
> and higher checking = (slightly) less power. I agree. 
>  
> I misunderstood Richard and thought he meant higher checking would
> give
> slower rep speed but after Ric. pointed out my misreading I re-read
> it
> and Richard was actually very clear. My "Oh" meant "oh, do I feel
> dumb
> that I didn't read it right the first time."  Sorry if anyone read
> more
> than that into it. I'm not mean spirited at all and would never
> intentionally offend anyone.
>  
> Thanks,
> Jim Busby
>