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

[Keith Roberts]

When I replaced the balance rail holes ala Spurlock, I drilled them slightly
smaller the first pass and they were tight, really close. I took a
1/8" chainsaw file that mics at .130 to .135 on the cutting surface and it
was tight so I inserted the file in the hole and rotated 1 turn
counterclockwise and removed. (I had to make a handle). They were perfect on
the new pins.
Lucky me.
So I ground off the back and sides of one of those files till I could taper
the hole until the key rocked nicely and leave the bottom untouched.

And when I checked them 2 years later they are still perfect.

Keith Roberts


On 7/26/07, Fred Sturm <fssturm at unm.edu> wrote:
>
>  On Jul 26, 2007, at 11:46 AM, Jim Busby wrote:
>
>  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.
>
> Takes a long time to insert those balance pins in each hole, and then pull
> them out later (I don't have a bunch of student helpers, so a few seconds
> here and there on each little procedure add up). I'm "reaming" with a drill
> bit, which doesn't remove as much wood as a real reamer, and maybe leaves a
> bit of "uncut splinters" (we're talking fairly microscopic) to hold glue if
> I need to size later. That's my reasoning, anyway. And I think it leaves a
> more stable condition than just putting in BR pins and letting the wood
> conform to them, if your holes are too small to begin with. I'm closer to
> having the right amount of wood (in this dimension, not to be confused with
> the reaming you are talking about above). Making the hole exactly the size
> of the pin will require a bit of easing. So I use one sizing caul, which is
> heated. The heat increases the size of the balance pin in the caul from
> .146" to .147", and the heat helps size the wood - make the size relatively
> permanent. It puts the hole .001" larger than the pin, very nicely and
> consistently. (Glue-sizing to make the hole smaller where needed is a
> separate part of the procedure, done only to holes that are too large).
>
>  Replace them on the Keyframe to check BR fit and fix pulley keys.
>
> That's a lot of time and work. I like to leave the keys in the clamp, and
> bring the balance pin to the key. I can feel that pin going into the hole
> very precisely, and also feel if there is any play in any direction..
>
>  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.
>
> Rick B is certainly correct in wanting to separate bottom hole from
> bushings, so one doesn't mask the other. I think I do it with a lot less
> time and effort. Putting a loose pin into the hole removes the factor of the
> weight of the key. All that lead can mask a lot of problems.
>
>  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 don't like having employees other than myself. That's one reason I am in
> this business <G>.
>
>  (I vote for you to write that book, sometime before your beard is
> entirely gray?? You and Ron. Oh well, Ron…))
>
> I don't think there's much chance of me compiling and writing in book
> form. But if anyone else wants to do that, and make use of what I have
> posted from time to time, that would be fine with me. Have at it with my
> compliments.
>
>  High regards,
>
> Jim
>
> Regards,
>
> Fred
>
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