[pianotech] Glue for hammers - question

[Ed Sutton]

Ron-

I don't understand your reply.

My impression is that as long as the glue holds the hammer on the shank 
without rattling or wobbling, that is probably adequate for tonal purposes. 
Other factors may cause someone to choose a particular glue.

Since the claim is sometimes made that hide glue is "acoustically superior," 
I'd like to hear the evidence (pun intended.)

Having used hide glue, carpenter's yellow glue (both straight out of the 
bottle and thickened) and Titebond Molding glue, my impression is that they 
all sound fine, as long as you get enough in the joint to make a good bond. 
If something is better, I'll adopt it.

Incidentally, Mr. Thorndahl said that with a few household chemicals, he 
could make hide glue behave like most of the bottled glues. I hope to get 
with him on this some day. I'd like to reduce my shop clutter.

Ed

----- Original Message ----- 
From: "Ron Nossaman" <rnossaman at cox.net>
To: "Ed Sutton" <ed440 at mindspring.com>; <pianotech at ptg.org>
Sent: Sunday, June 07, 2009 10:19 PM
Subject: Re: [pianotech] Glue for hammers - question


> Ed Sutton wrote:
>> I am curious what the arguments or evidence may be for the tonal 
>> superiority of a rock solid hammer to shank joint.
>>
>> A rattling joint is not good, but what is lost if there is a small degree 
>> of flexibility in the glue?
>>
>> The hammer felt itself is definitely flexible by design, and not rock 
>> hard.
>>
>> The hammer is not being driven when it reaches the string, it is moving 
>> by its own inertia.
>>
>> It is generally considered desirable that the hammer stay in contact with 
>> the string a period of time, and not rebound instantly.
>>
>> Eugene Thorndahl, the former glue chemist at Peter Cooper, suggested to 
>> me that a small amount of glycerine added to hide glue would give it a 
>> little more flexibility, and produce a more dependable hammer joint, but 
>> he was addressing the strength of the joint under stress, not acoustic 
>> issues.
>>
>> Ed Sutton
>
> And don't forget the action bedding, and the flange pinning, and the 
> backcheck height (2mm below the tail at drop), and the front rail 
> punchings, and the coupling of the casters to the floor, and the room 
> acoustics, and the front leading in the keys (for inertia control), and 
> the hammer needling and lacquer application techniques and locations, and 
> the duplex scale tuning, and, of course, the A-4 pitch and temperament 
> choice. Why, with all this sterling ammunition, are these things still 
> being endlessly debated as if they were real? All evidence considered, it 
> doesn't seem to much matter, since it's not apparently possible to make 
> the right set of choices in *any* specific situation.
>
> If all this nonsense still hasn't been hashed out by now in the real world 
> of day to day piano service, what's the point?
> Ron N