knocking keyframe

[RobertD429@aol.com]

Hi again, Avery. You wrote:

>   There is a knock on each end with all pressure removed and with the glide
>bolts up, and no knocking anywhere else. I think I'm going to order the
>adjustable guide plates that several have mentioned to me. We sometimes go
>through some pretty wide humidity changes in this area so I think I would
>like that "adjustability" the other plates would give me. I believe, for me,

>that would be easier than moving the guide pin. Also, probably less chance
of
>error on my part.
>   I'll probably also sand the bottom of the key block some so that I can
>replace the shims on the from of the block. That will also give me some room

>for variances in humidity.
--------------------
I expect from your description of the knock that you won't find anything
bizarre with the bottom of the keyframe. I was just wondering why the pin was
low -- it sounded suspicious !

We're lucky in my part of California not to have very wide humidity swings,
so our guides (and tunings) stay pretty stable. It sounds like you might
benefit from the adjustable ones, though.

I'd still keep moving the pin an option, depending on how your new guide
fits. Sanding the keyblock enough to add shims will change the position of
the fallboard by moving its hanger either outward if you sand only the front
of the block, or downward if you sand the whole block. It would also change
the angle of the keyblock dowels. Moving the pin is no big deal. While it's
wonderful if you get the hole perfectly parallel to the keybed, any small (I
say small) error can be taken care of by bending the pin. It needs to be
supported so it won't tear out the frame. For instance, to bend it down,
support it with a small block at its point of entry, and tap down with a
small hammer on another block at the pin's end. To bend it up, reverse the
process; support it at the end and tap at the point of entry. Pad the hammer
with leather to avoid marking the pin.

I keep thinking of more details, but this is the last one, I'm sure. I doubt
this is the case in your situation, but I've also found dirt or a piece of
paper clip or other debris in the holes in the keybed the dowels go into.
They of course keep the block from seating and make it too high.

Bob Davis
Stockton, CA