[CAUT] Steinway extra-bore-length

[David Love]

So the standard bore of 1 15/16" in the tenor treble increased to 2  1/16"
was the difference between being able to get the hammers under the block?
If that's the case then practicality reigns supreme.  Use the maximum bore
that still allows the hammers under the block and angle the hammers back to
get them at 90 degrees at string contact.  There are many examples of pianos
that do this without any problems and an extra 1/8" of travel requires a
minimal angling especially when combined with the upward slope of the
strings from termination to bridge.  

 

David Love

www.davidlovepianos.com

 

From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Mark
Cramer
Sent: Tuesday, June 01, 2010 8:43 PM
To: caut at ptg.org
Subject: [CAUT] Steinway extra-bore-length

 

A week or so back,  Jon Page mentioned the correct method of calculating
hammer-bore length. 

Thanks for that Jon, it's the same method we use, excepting where the
hammers are deliberately pitched, but here's a funny story from a few
years... okay, a decade ago:

I was preparing hammers for a 1980's D and found that bore length worked out
about 3mm (1/8th) longer than spec. Since we tend to buy our hammers
un-trimmed and extra-length, it was no problem to bore them with plenty of
tail length. As a caution, I tested samples on the bench and all was fine.
Fine... until installing the action that is.   

The action wouldn't fit back in the piano... even with the shanks buried in
the cushions, no deal! (that was the chuckle part, the rest is pretty
boring, but I do have a question)  

So, we thinned the cushions and even shortened the balancier height
adjustment screws. All worked wonderfully, and three years later I repeated
the dimensions with the next set of hammers. 

Three years later again, I was pressed for time and ordered some pre-hung
aftermarket hammers. The supplier was quite adamant that the hammers be
bored to original spec, even though this would result in over-strike.
Knowing I had room to push the action back (return to factory position), I
went along with their advice, even though it meant replacing cushions, etc.

Now it is "three years later" yet again, and time for fresh hammers. 

I really like the idea of the hammers being at right angles to the string,
and the shanks horizontal at strike, which is the result we get with Jon's
measurements. However, I wonder about the implications of the extra-long
bore... aside from the need to get the action in and out of the piano that
is.        

Raising the stack (3mm) would take care of things, but this is really a very
efficient action, and I neither want, nor see a need to tamper with that.
What's more, I can't say I really noticed a difference in performance with
either bore dimension.

The Question:

So, what are the rest of you (and Jon) doing in this situation, and why?

thanks,
Mark Cramer, RPT
Brandon University



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