To Rake or Not to Rake

[gordon stelter]

Which is why I suggested that you might want to
rebuild those "goofy" Knabe butts, rather than replace
them with new stuff. I have a bucket full of these,
from an 1893 piano, and I also have an 1899 piano. If
you need some measurements, just ask. If you want to
buy the bucket of 1893 butts and hammers, let's talk.
     Thump

--- Bill Ballard <yardbird@vermontel.net> wrote:
> Interesting question:
> 
> I'm reinstalling a set of new upright hammers on a
> piano (100 
> year-old Knabe) which should have had new butts
> under them. In 
> measuring the hammer bore specs, the one thing I
> notice is that the 
> rake in the top section is 0º (with the rest of the
> hammer boring 
> being a standard 5º). I've talked with the
> technician for whom I'm 
> doing this, who says that the boring is the supply
> company's, and 
> they followed whatever was on the original samples.
> 
> New butts and shanks along with however I choose to
> do the reboring 
> of the replacement hammers. I can get the hammers to
> hit their strike 
> points regardless of the rake. Just a matter of
> shank length. I'd be 
> inclined to use the rake in the lower sections. I
> was remembering 
> that this morning, at the piano, I was confirming
> the strike point on 
> string #88, using the original shank and replacement
> hammer (at 0º 
> rake), busted out of the "dead-meat" butt (go ahead,
> RicB, I dare 
> you...), that the hammer was striking square to the
> string, and that 
> after a little hammer reshaping and then locating
> strike point #88 it 
> sounded promising.
> 
> That was with the new butt as well (Pratt-Win). The
> interesting thing 
> is that when I get an old and new butt side by side
> with action 
> centers matching and the top surfaces (with the
> bore) parallel, the 
> shank on the new butt leans backwards by 4º. So
> re-introducing a rake 
> in the hammer bore added to this extra angle in the
> butt's bore will 
> actually swing more the butt's center of gravity
> closer to above the 
> center pin.
> 
> The 0º rake starts at #72, which is about halfway
> through the top 
> section, so if I had to bet, I'd say that it was
> somebody's accident.
> 
> As I said, in inclined (pun intended) to make a
> constant rake. But if 
> anyone knows what advantage there might be to a 0º
> rake in the top 
> octave, I'd be happy to hear about it.
> 
> Bill Ballard RPT
> NH Chapter, P.T.G.
> 
> "If you are in a dilemma about where to park your
> car, ask your 
> hostess. If she is engaged, ask some responsible
> person who can 
> indicate a convenient spot"
>      ...........Betty White's Teenage Dance Book
> (paperback, 1959)
> +++++++++++++++++++++
> _______________________________________________
> pianotech list info:
https://www.moypiano.com/resources/#archives


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