Bechstein B hammer rake

[Stéphane Collin]

< Hi Ric.

< Comments interspersed

We just went through a rake thread a bit back where several asserted that
its best to have the hammer at exactly perpendicular to the strings at
impact. 

< I (but who am I?) am definitely convinced that the perpendicular condition
is required for maximum power, certainly in the top last quarter of the
scale.


Strings angle up to the bridge from the striking point so an
backwards rake would just make the angle between hammer and string at
impact even farther away from this stated optimal.

< Ar, depends on the bore length, not ?  Do you use the dummy spare hammers
with known bore length trick to accurate the bore length measure ? It
shortcuts all measurements failures and approximations, including the less
than optimal keyboard frame bedding and the said strings angle up (or down).
I can't remember who brought up this trick, but it is one of my top 5 tricks
ever learned on this list.

I cant really see the rational for the original rake...which seems very
very consistant all the way up to the last 6 - 7 highest notes where the
rake becomes nearly 0 degrees to the shank.

< Me neither, to be honest.  The most clever comment about that came from
John Delacour, who considered that the distance between shank center pin and
hammer molding center was fixed by design, which makes sense in the way the
back checks for example are also at a fixed place offering the exact catch
angle if there is such a thing, and also that the strike line is considered
to be very accurate and really ideally straight from section to section
(which I doubt in real life, but which can come up astonishingly true on
certain Bechstein models).  John said that he then aims for the right rake
to obtain the perpendicular with string at impact condition, everything else
being observed.

I know Bechsteins have this tight fit at the top few notes of the
highest two sections... but am wondering if there is any reason why I
shouldn't use a 1-2 degree rake forward on this instrument.  This looks
to be pretty close to whats needed to get the hammers perpendicular to
the strings at impact if bore length is taken as string height over the
key bed minus. hammer shank center height over the key bed.  I usually
just make hammers perpendicular to the shank but wanted to try this
other since several folks recommend it so much.

Advice appreciated.

< For what mine might be worth.

Cheers
RicB