[CAUT] Steinway extra-bore-length

[Mark Cramer]

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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