[CAUT] Key bottoms (was Re: key-easing pliers?)

[Jim Busby]

Fred,

 

One difference/question I have is - isn't it easier to insert the proper
sizing cauls, then turn the set upside down and insert the BR pins (the
cauls won't let the pins fall through), then add sizing fluid? After
they dry, ream the mortise so the "foot" of the hole is the exact
thickness. Replace them on the Keyframe to check BR fit and fix pulley
keys. Many times pulley keys are no longer an issue with the glue sizing
formula. BTW I use a much diluted (12/1 or so) Elmer's glue for sizing.
Ron N. tells me that this is the only place on a piano where he uses
that glue. (Thanks Ron) There is no sound, click, etc. with Elmer's glue
as there is with PVCE, Hot Hide, and or other glues.

 

Baldassin taught me to add this extra step (it really doesn't take long)
of placing the keys back on the frame BEFORE the bushings are in so that
you can work the BR holes w/o "false readings" from overly tight new
bushings. It takes about 10 - 15 minutes longer but the total focus on
the BR hole pays big dividends, IMO. Here is when I deal with the pulley
keys because now you're sure of which ones weren't fixed by the glue
sizing.

 

Anyway, just a bit more to consider for your book... Who knows?
Marriott's success, he said, was to "write out every tiny process and
revise it in writing until nothing more could be perfected, then get all
your employees to do it THAT way."

 

(I vote for you to write that book, sometime before your beard is
entirely gray?? You and Ron. Oh well, Ron...))

 

High regards,

Jim

 

________________________________

From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of
Fred Sturm
Sent: Thursday, July 26, 2007 8:00 AM
To: College and University Technicians
Subject: [CAUT] Key bottoms (was Re: key-easing pliers?)

 

On Jul 25, 2007, at 11:03 AM, Mark Cramer wrote:





BTW, Bill's system is absolutely beautiful! I think we started with the

cauls in 95 (?) then added the heated-broach system (thank-you Master

Wolfenden!) from Pianotek, and finally the mortise-sizing cauls,
whenever

they became available.

 

With the control over key-pin, mortice and cloth sizing, so little
variable

remains. We record the cloth and heating broach size (as many of you do)

right on the key-board and in our records.

 

I couldn't agree with Mark more on how much better work is possible with
current techniques, tools and materials. The fly in the ointment for me
has been bottom holes. I have wished for years I could finish the
bushing job, take the keys from the clamps, put them on the pins and be
done (essentially, with very, very minor tweaking). But I find bottom
holes slow this considerably, needing custom work on most keys after
steaming out bushings. I've tried a lot of ideas, and none were quite
satisfactory. But I have finally come up with a system I like, which
takes me under 20 minutes, keys in clamps.

 

1) Check for holes that are too large, for sizing. Keys laid balance
holes up, take a loose balance pin and insert in each hole. If a hole is
loose enough the pin wants to fall in, wiggle the pin in the hole. If
there is any chatter, chalk it and move on. Size the chalked holes with
your favorite method.

2) Remove excess wood where present. I know, lots of "experts" have told
us for years we should "never remove wood" here. They are wrong. We
should never remove _too much_ wood here. Eric Shandall is now teaching
use of parallel reamers for the purpose of easing too tight balance
holes, in Steinway factory seminars. He uses .1470, .1475, and .1480 I
believe, usually finding .1475 best. These are available on the web for
maybe $10 each.

            I decided there was too much danger of taking too much wood
using a reamer, and anyway I don't need yet more tools to keep track of,
so I decided to try a drill bit instead. #26, from a #1 - #60 set, is
.147. (If you feel paranoid about humidity swings and whatnot, use #27,
.144". And, obviously, if the keypins are a different size, change
accordingly). My technique is to push the bit into the hole by hand (no
twisting) and pull back out. If the hole is particularly small, I repeat
once or twice. To make it easier, I attach a stop collar to the bit (a
pin vise would work). With a new, sharp bit, the flutes will cut pretty
well. I find I mostly remove some splinters and some black sticky
residue.

3) Heat size, using a home made caul in the keybushing iron setup (heat
controlled soldering iron). Short piece of 1/4" brass, drill a hole with
#27 bit (.144"), pound in a balance pin cut in half. Use it like ironing
keybushings: about the same temperature and same time. No more than 1.5
seconds per hole. (The idea comes from Brian DeTar, who used something
similar for sizing damper guide bushings. I have three similar things
for that purpose, with #6, #7, and #8 bridge pins as the "irons. Works
great!)

4) Even up key bottom thickness, using a balance hole reamer (idea of
doing the whole set, as a common procedure, courtesy of Roger Jolly).
Keys are held vertical, so that you can get at both sides at once.
Insert through the top of the key, gauge how much should protrude
through the bottom hole by eye and by feel (I guess you could make a
stop gauge of some sort if you wanted to). Go through the whole set
doing the same to each key. Sometimes this is a formality, sometimes it
was really needed. I guess this step might go earlier in the process,
before you even glue in key bushings, so chips can be easily knocked
out. 

5) Ease with balance hole easer, to make holes tapered. First feel holes
with a loose balance pin. THey should be pretty consistent, with a
little friction resistance. Find one with fairly high resistance. Insert
the easer from the other side and ease. Feel with the pin. When you have
it so that there is next to no friction, and no chatter at all, remember
the feel and distance the easer is protruding through the bottom. Match
that for every key. At first, you might check every key or so with a
pin, until you feel confident. But this can be done quite precisely and
easily, now that all holes are so consistent. If you like, make a stop
gauge for more control and consistency, if you don't trust the feel of
your hands and your eyesight.

            Now take the keys out of the clamps and install. Eureka! It
works! Perfection at last! 

            Next time for this set of keys, steps 2 and 4 can be
omitted.

 

Regards,

Fred Sturm

University of New Mexico

fssturm at unm.edu

 

 

 

 

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