Balance rail felt

[V T]

Hello Bob,

I proceeded with some experiments:  I have all the
Pianotek balance rail punchings, so I measured the
compression on them for a given force (nothing
elaborate - just a simple comparison).  Then I ironed
them and measured again.  Interestingly, the thinnest
punching (1mm) was not the low compression winner
after ironing!  The 1.8 mm part was firmer after
ironing.  I am letting them sit without compression to
see how much they spring back.  I suspect that the 1.8
mm part will be worse than the 1 mm part in a few
days.  Just for reference, the 1 mm part would
compress about 0.006" before ironing and 0.003" after
ironing.  The 1.8 mm punching would compress 0.009"
before ironing and 0.002" afterwards.  I expect that
heat has a different effect from compressing on a
threaded rod, so I will repeat that experiment with
Ron's method.

I somewhat dislike the key leveling process and I
don't make it easy on myself by refusing to use the
split paper punchings.  I have observed key height
variations of as much as 1 mm with humidity changes,
so I am determined to do something about it.  Of
course, the key height is also determined by the
stability of the back rail cloth, so to do it right, I
will have to find the combination of balance rail
punchings and back rail cloth that tracks well with
weather change.  I am equally concerned with the
absorption of power in soft balance rail punchings.

Best regards,

Vladan
==============================================

Ron's idea of compressing the punchings on a rod
sounds good.  I've been taking them (regular felt
balance rail punchings form pianotek) one by one and
hammering them on the concrete shop floor before
installing.  This obviously compresses and I don't
think that rethicken enough to be concerned.

Bob Hull

> 
> >If anyone has done a survey of balance rail felt
> >punchings, could you please let me know who is
> selling
> >the thinnest, hardest ones (as little compression
> as
> >possible).  Thanks!
> >
> >Vladan
> 
> Yup, hitch pin punchings. I store a half dozen sets
> or so (90-100 each) on 
> threaded rods, thoroughly pre-compressed by a couple
> of nuts and cardboard 
> punchings at the ends so they won't pack and settle
> much after installation.
> 
> Ron N


		
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