[CAUT] Bore distances for Steinway L

[David Love]

Which illustrates the danger of choosing the knuckle hanging dimension
before knowing the hammer weights and corresponding match to the overall
leverage.  Of course, to be fair, we don't know how much lead is in the keys
either.  Maybe it's minimal.  Judging from the regulation specs you are
getting it seems like the overall leverage would have to be on the lower
side of things.  I wouldn't worry about the gap between the shanks and the
rest cushion.  Determine the proper blow distance first to go with your
targeted dip.  If you are able to regulate the whole thing with reasonable
compromises between dip and blow and the shank/rest cushion gap is too great
you can always build up the rest cushions.  Keep in mind that sometimes the
sharps have a different key ratio than the naturals and may require amount
of dip.  You might have to raise the starting point if they are burying or
consider raising the hammer line overall.

 

David Love

www.davidlovepianos.com

 

From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Paul T
Williams
Sent: Thursday, May 27, 2010 2:13 PM
To: caut at ptg.org
Subject: Re: [CAUT] Bore distances for Steinway L

 

Hi Ed, 

 Yes, I ran out of keydip, but increasing blow distance to .410 has helped a
great deal, but still am having trouble with the sharps. The naturals have
turned out nicely now with an increase in dip without being dramatic. The
sharps, tho are getting very close to burying, but not quite...very close.
I checked other L's around the school and found that they are nicely
regulated with slightly less than 1/8" clearance above the naturals.  On
this beast, the clearance needs to be more like 1/16"above the naturals
which is really weird.  The knuckle to centerpin is just 16mm, like what I
replaced. Sharps are exactly .5" above the naturals. 
I checked the distance from shank to rest cushion, and it's a bit high, but
not nasty...like 1/4"...higher than I like to see. 

This is the weirdest action I've ever dealt with, and I've done lots and
lots over my years in this crazy biz!.  The bass section is getting close,
and I'll try tomorrow to raise the blow on the treble a bit to see what I
get with that. i've regulated the naturals in the treble, and strangely, it
is coming together rather nicely, although the DW is huge.  The next problem
to deal with. I see that the tapering was minimal, so I can trim the hammers
some to get some weight out of the hammers. The DW is starting out above 60g
all over! 

This action is driving me nuts! 

Thanks for all the help to you and all.  I will defeat this beast! 

Best, 
Paul 










From: 

Ed Foote <a440a at aol.com> 


To: 

caut at ptg.org 


Date: 

05/27/2010 01:55 PM 


Subject: 

Re: [CAUT] Bore distances for Steinway L

 

  _____  




 Ok, I might be confused:

paul said 
The key level and dip is factory perfect, I've got the proper blow distance
of 1.75". I can't get let off any closer than 1/4"!! The rebuild was done
right and the plate is the same height as before.  I've even tried to raise
the blow a bit, and still can't get it to let off correctly. The frame is
perfectly bedded.  The wips are old, but in pretty good shape. 

then later posts: 

>>The buttons are original and plenty of room both up and down compared to
the rail.  

Is the problem that you run out of keydip before going through escapement?
If so, you have too much leverage in the action.  I would recheck the
knuckle to center pin distance.  This sounds like 17 mm shanks being put on
a whip/key assembly that works with a 16 mm. 

>>I decreased the blow a bit, increased the dip a bit. 
How much is too much of either? <

Your dip will be limited by your sharps.  They can't bury under the keytops,
and they can't be much more than .500" above them.  Set them .5" over the
naturals, then set the deepest dip possible and raise then raise the blow
until you have the amount of aftertouch you need.  If it is too high, you
will need to change the ratio,(either capstans or knuckles)

>>I can't raise the bass hammers any farther or I won't be able to get the
action in or out.

If the shanks are more than 3/8" off the rest cushions, you risk
catastrophic action failure, so there are other limits on shortening blow
besides action clearance.
Regards,

Ed Foote 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://ptg.org/pipermail/caut.php/attachments/20100527/b2bc8ce0/attachment.htm>