
Introduc on
7
July 2013
Piano Ac on Regula on
This
discussion
is
not
intended
to
be
a
complete
course
on
grand
ac on
regula on,
but
rather
may
prove
helpful
in
restoring
the
ac on
to
proper
performance.
Proper
alignment
of
ac on
parts,
and
key
easing
are
all
very
important
steps
in
the
regula on
procedure.
The
following
procedure
assumes
that
this
preliminary
work
has
been
checked
and
performed
as
necessary.
Before
removing
the
ac on
from
the
ac on
cavity,
evaluate
ac on
regula on.
If
the
ac on
is
not
well
regulated,
proper
perfor
‐
mance
of
the
system
cannot
be
expected.
During
the
installa on
process
of
the
PNOma on
II
Player
System,
it
is
quite
possible
that
ac on
regula on
will
be
directly
a
ff
ected.
A
por on
of
the
keyframe
and
back
rail
cloth
will
be
removed
so
that
the
note
solenoid
plungers
can
contact
the
keytails.
This
opera on
may
cause
the
keytails
to
be
lower
than
their
original
posi on.
The
result
of
lower
key
tails
is
an
increase
in
both
key
height,
and
hammer
strike
distance.
Restoring
the
strike
distance
to
speci
fi
ca ons
by
turning
out
the
capstan
screws
is
not
the
proper
remedy.
Always
re
‐
work
the
back
rail
height
so
that
the
key
height
is
at
its
original
posi on.
‐
Are
the
keys
level?
‐
Do
the
hammers
let
o
ff
1/8
in
the
bass,
tapering
to
1/16
in
the
high
treble?
‐
Is
the
drop
1/16
below
the
point
of
let
‐
o
ff
?
‐
Is
the
hammer
line
straight?
‐
Are
the
hammer
shanks
approximately
one
shank
thickness
above
the
hammer
rest
rail?
‐
Is
there
adequate
a er
‐
touch?
With
the
ac on
on
a
fl
at,
clean
workbench,
measure
and
record
the
following:
Natural
key
height
at
bass
and
treble
ends.
Sharp
height
above
naturals.
Key
dip;
both
naturals
and
sharps.
The
height
of
the
fi
rst
and
last
hammers
in
each
sec on
of
the
ac on.
Replace
the
keys
and
ac on
stack
on
the
ac on
frame.
Refer
to
the
regula on
measurements
recorded
earlier
to
see
if
regula on
has
been
a
ff
ected
by
the
modi
fi
ca ons
to
the
ac on
frame.
If
key
height,
key
level,
or
strike
distance
are
di
ff
erent
than
previously
recorded,
steps
must
be
taken
to
restore
proper
regula on.
To
restore
key
height,
replace
the
back
rail
cloth
with
one
of
a
thicker
dimension.
Remove
the
ac on
stack
and
keys.
A er
removing
the
old
back
rail
cloth,
be
sure
that
all
traces
of
glue
have
been
removed
from
the
back
rail.
Replace
a
few
of
the
end
keys
and
try
various
thickness
of
back
rail
cloth,
without
glue,
to
ball
park
the
correct
key
height.
Light
fi
nger
pressure
on
the
capstan
screw
will
approximate
the
force
that
is
normally
on
the
capstan.
Set
key
height
with
the
back
rail
cloth
at,
or
slightly
below
the
desired
key
height.
When
you
are
sa s
fi
ed
that
you
have
the
best
choice
of
back
rail
cloth,
glue
the
material
to
the
back
rail,
leaving
the
rear
edge
unglued.
Name
board
felt
is
available
in
a
few
di
ff
erent
thicknesses,
and
can
be
used
for
fi
ne
adjustments
when
glued
under
the
back
rail
cloth.
Although
key
height
can
be
reestablished
quite
accurately
using
the
above
procedure,
some
key
leveling
is
to
be
expected
when
replacing
back
rail
cloth.
Remember
that
subsequent
ac on
regula on
adjustments
will
a
ff
ect
those
already
performed.
To
prepare
the
ac on
for
fi
ne
regula on,
do
the
following
quickly:
Check
or
set
repe
on
lever
height
so
it
is
slightly
higher
than
the
jack.
During
your
fi
nal
regula on,
trip
the
jack
tender
with
your
fi
nger
and
release
it
slowly.
If
regulat
‐
ed
properly,
you
will
be
able
to
feel
the
jack
brushing
the
knuckle
as
it
is
released.
The
jack
must
return
completely
under
the
knuckle.
Set
strike
distance
to
1
3/4.
Be
sure
that
hammer
shanks
are
above
the
rest
rail.
Check
or
set
jack
posi on
so
that
the
back
edge
of
the
jack
is
aligned
with
the
back
edge
of
the
knuckle
core.
Set
let
‐
o
ff
1/8
from
string
in
the
bass,
tapering
to
1/16
in
the
high
treble.
Make
sure
that
you
have
some
drop
a er
escapement.
Set
drop
to
1/16
below
let
‐
o
ff
.
With
the
above
preliminary
steps
completed,
level
keys
as
necessary
to
their
fi
nal
speci
fi
ca on.
Note
that
with
key
height
at
the
same
speci
fi
ca on
as
it
was
before
ac
‐
on
frame
modi
fi
ca on,
key
dip
should
be
correct
(assuming
that
the
dip
was
correct
prior
to
the
installa on
procedure).
Also,
damper
li
ming
is
reestablished.
Check
or
set
repe
on
spring.
The
spring
should
carry
the
hammer
upward
with
a
steady
mo on,
without
kicking.
With
the
preliminary
ac on
regula on
done,
you
are
ready
to
establish
the
strike
distance
and
key
dip
measurements
that
will
result
in
proper
a er
‐
touch.
Since
the
key
height/key
dip
rela onship
has
been
reestablished,
consider
varying
only
the
strike
distance
to
get
the
proper
a er
‐
touch.
If
you
are
working
on
an
older
instrument,
consider
varying
both
strike
distance
and
dip
to
arrive
at
an
acceptable
compromise.
Select
sample
keys
with
which
to
work,
like
the
fi
rst
and
last
two
keys
in
each
sec
‐
on.
Depress
your
fi
rst
sample
key
very
slowly,
stopping
its
movement
just
a er
let
o
ff
.
Look
to
see
if
there
is
addi onal
key
travel
le .
If
there
is
no
addi onal
key
travel
a er
the
let
o
ff
point,
there
is
no
a er
‐
touch.
Key
dip
will
have
to
be
increased,
or
strike
distance
will
have
to
be
decreased.
If
there
is
too
much
addi onal
key
travel
a er
the
let
o
ff
point,
the
hammer
may
block
against
the
strings
when
the
key
is
played
fully
into
its
dip.
Key
dip
will
have
to
be
decreased,
or
strike
distance
will
have
to
be
increased.
Be
sure
that
the
sharps
have
the
same
a er
touch
as
the
naturals.
As
a
second
check,
see
that
with
the
key
fully
depressed,
there
is
s ll
some
travel
le
at
the
jack
tender.
When
you
have
the
key
dip/strike
distance
established
on
your
samples,
set
your
key
dip
to
your
established
speci
fi
ca on
uniformly
throughout
the
ac on.
You
are
now
ready
for
the
fi
nal
regula on.
Using
your
new
strike
distance
measurements,
carefully
repeat
the
above
outlined
steps
for
the
fi
nal
me.
Summary of Contents for PMII
Page 26: ...Installa on Procedure 26 July 2013 Installing the Steinway Sostenuto Assembly Order 70897 ...
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