Balance pin holes

[Roger Jolly]

Hi Richard,
                A couple of suggestions.

Easing should always be done from the top of the key with a Yamaha style
bushing hole reamer.
The easing should be be done by rotating the tool with little or no
downward pressure. A little at a time
is the key, ( no pun intended <g>) the key should just slowly slide down
the pin.
Before reaming check the balance rail bushing to make sure this is not
causing the problem. 0.002" is the desired clearance for balance rail
bushings.

Sizing holes.

#1  A very wet cloth over the hole and press with a steam iron this will
swell the hole quite a bit.
#2  to swell holes and improve the key bushings.  I use a set of Accu Cauls
inserted into the mortice, and then steam the B/R hole with a fine jet of
steam for a whistling steam kettle, (whistling thingy removed.Heck I'm
nut's enough all ready)  Swells the hole up nicely, as well as swelling up
the bushing cloth. Leave cauls in place over night to dry. Next day you
will be suprised that most of the cups have disappeared and you will have
to lightly size the holes.
#3  Glue sizing, use 50% white glue and water, once the glue has fully set
you will find it will be a little more elastic than carpenters glue, and
less lightly to click. 
#4   CA glue is a fast and nasty fix for sizing, but it clicks and is not
recommended for a good piano.
But for an old clunker and a client that has no money, who am I to judge.
Better than an unstable key.
#5  Saw kerfing the hole and inserting a slip of veneer, text books shave
this well covered.
#6   Routering off an 1/8" X  2" from the bottom of the key and inserting a
maple shoe, you need to establish two centre line on the key stick before
routering to define where you will drill the hole after glueing the shoe in
place. After drilling the hole you need to counter sink the hole so that
only about 1/16" comes in contact with the pin.

As a foot note, I always check the front rail bushings for tightness before
tackling the B/R, the standard is about 0.005" just a perception of side play.

ALWAYS, ALWAYS,  front rail first. Go slowly for the best results, you can
not un squeeze a bushing.

I think there will be some photos in next months Journal.

\Regards Roger

At 11:12 PM 23/02/00 +0100, you wrote:
>Hi list.
>
>It has come to my attention that I should seek advice on proper sizing
>techniques for balance pin holes in keys. I find often that these are
>too tight (symptom... keys ride up the pins with play making key
>leveling an impossibility). Yet as known if they get too loose you get
>checking problems.. noises.. and other un-nice results.
>
>I need someone to write out a complete description of the entire hole
>preperation process. Not just sizing the bottom of the key.. but the
>whole tomato..grin
>
>Newton.. you are great with this kinda thing.. so if you got the time..
>or anyone else for that matter. I would be most apreciatofortisimo.
>
>--
>Richard Brekne
>Associate PTG, N.P.T.F.
>Bergen, Norway
> 
Roger Jolly
Saskatoon, Canada.
306-665-0213
Fax 652-0505