Chickering Quarter Grand Pinblock - another way.

[Nick Gravagne]

Hello Kendall,

 

Thanks so much for your detailed and thoughtful reply to my Chickering
pinblock question. The two-piece idea had occurred to me but I dismissed it
thinking that my old workhorse bandsaw didn’t have enough height (or maybe
power) to work with. But perhaps it does; I will have another look. Also,
the thought of having to resaw the new Delignit material seemed too
daunting. I will revisit these ideas and make some measurements. I can at
least do the short bass section using this method as a trial run for the
longer piece.

 

The whole process generally appeals to me as it avoids working “blind” as to
the hidden step.  I will get back to this post when I have more information.

 

And Kendall, if it really isn’t too much trouble, I would like to avail
myself of those photos you so generously offered to email me.

 

Thank you.

 

PS And thanks also to Will Truitt for his detailed additions, as well as to
Ron N, PR Jones, and Dean May. It all adds up when there are so many “go-to”
folks out there!

 

 

Nick Gravagne, RPT

Piano Technicians Guild

Member Society Manufacturing Engineers

Voice Mail 928-476-4143

 

  _____  

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Kendall Ross Bean
Sent: Sunday, July 20, 2008 2:25 AM
To: 'Pianotech List'
Subject: RE: Chickering Quarter Grand Pinblock - another way.

 

Nick~

 

There is another way of fitting the two step pinblock. I don't know if it is
easier or faster than the router table set up, (I haven't tried the router),
but this worked well for us. It involves different tools. (No router.) One
of the problems with a router setup is that the old pinblock sections
sometimes have shrunk away from the plate flange, so if you are using the
old pinblock as a pattern or template that way, you could still be off.
(Also the router method requires a lot of setup IMHO) The method I used
allowed me to individually fit each individual "step" to its respective
flange on the plate, just like you would a normal pinblock. If you only want
to get "close" to the flange profile and then make up the difference by
glassing, I guess that's possible too.

 

Consider the two step pinblock as two layers that can be "disassembled".
Measure the overall thickness of the old pinblock, and figure out how thick
each layer needs to be. You will be sawing the old pinblock apart, into two
layers (or two individual steps). (By the way, this works for all sorts of
other double step pinblocks as well. It's how we used to do Victorian
Steinways.) Each one of these old pinblock "layers" can be used as a pattern
to make the layers of the new pinblock, which can be individually fitted to
the plate flanges/recesses, and then glued together, using the plate itself,
and clamps, as a fixture. (Just as you would a normal pinblock, make each
layer slightly oversize so that it can be fitted to the flange.) Drill the
machine screw holes, after the assembly is glued together, in such a way
that the bevels on the flathead machine screws pull the block tightly
against the plate flange,  then mark the tuning pin holes with a machinist's
punch. Remove the glued up pinblock from the plate recess/flange and drill
it on a 7 degree tilting table on the drill press (or if you want, you can
drill it in the piano, if you have the set-up to do that).

 

If you have a bandsaw that has sufficient height (I have the Delta with the
height attachment, but you may not need it -  as I remember the Chickering
pinblock wasn't that deep/wide) you can easily saw the old pinblock apart
into the two layers. The bandsaw does make a kerf, so that's why you need to
know the thickness before you rip the old block apart. If you use a
relatively narrow blade on the bandsaw (say 3/16' or 1/4 " x 10 tpi) it will
tend to deflect backwards rather than curving to the side, making a
straighter cut than a wide blade. (A trick I learned from Mark Duginske's
Bandsaw Handbook). I use a ripping fence on the bandsaw that is angled to
compensate for the bias of the blade (have to change it for every blade) but
you can just eyeball it as well, or use one of those little resaw point jigs
to keep the pinblock vertical while you try and follow a pencil line or the
side of one of the "steps".

 

You'll need to make new pinblock layers that are the same thickness as the
ones you cut from the old pinblock, plus the kerf. It's easy to make these
from stock pinblock panels using a bandsaw to "resaw" them to proper
thickness, and then a planer or jointer to surface. You can try to duplicate
the original lamination thicknesses, using different types of pinblock
blanks, or you can just use something like Delignit.

 

Some pinblocks, we were able to separate the laminations into two layers
with a putty knife or chisel. They just sort of fell apart. Others are
better sawn.

 

I believe I used dowel centers to locate the machine screw holes in the new
pinblock. You can also try using the old pinblock as a drilling template,
but that's dicier.

 

I seem to remember on the last quarter grand I did there were basically two
pinblock sections, a bass (short), and a treble (long). But other
Chickerings we have done have different configurations. One larger grand had
four individual pinblock sections.

 

If you want, I took quite a few pictures of the operation I can e-mail you,
and give you more details with the actual sequence. It actually went quite
fast, from what I remember.

 

Sincerely~

 

Kendall Ross Bean

 

PianoFinders

www.pianofinders.com <http://www.pianofinders.com/> 

e-mail: kenbean at pianofinders.com

 

Connecting Pianos and People

 

  _____  

From: Nick Gravagne [mailto:gravagnegang at att.net] 
Sent: Saturday, July 19, 2008 5:23 PM
To: pianotech at ptg.org
Subject: Chickering Quarter Grand Pinblock

Hello All,

 

I have found myself knee-deep (and delightfully so) in an authentic
Chickering Quarter grand rebuild (belly job only).  

 

Questions: most of us know about the machine-screwed, two-step pinblock fit
to the two-step plate flange (ouch). I understand per my fellow tech and
friend, Les Conover of Albuquerque, how to fit the new block using a
straight ¾” router bit and a router table set up. Any other (aka simpler?)
ideas out there?

 

Also, I would like to replace the agraffes, but the original threaded studs
are slightly smaller in diameter than the standard size available today. Has
anyone re-bored and re-tapped the holes to accept a standard ¼” stud?  Or
might it be better to remove and recondition the existing agraffes?

 

Progress thus far: the crowned soundboard is made and fitted to the case;
the bridges are underway; and it is now time to begin thinking seriously
about the block.

 

Thanks for your consideration.

 

 

 

Nick Gravagne, RPT

 

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