Lyre braces

[Ted Sambell]

Susan,

Your point about overtightening the lyre braces is well taken; I mentioned
it too. But I feel it raises another issue, which is the design of the
modern pedal lyre. In the dry climate of this part of the world, it is
almost a given that the posts will come loose. In his book, 'Understanding
Wood' Bruce Hoadley points out the difficulty with the round tenon type of
joint. Even when wedged it is vulnerable to loosening from shrinkage.
Yamahas and Kawais here nearly all loosen in time. Dismantling the lyre is
virtually impossible without damage, as each joint is double wedged, and the
wedges are driven in so hard that the tenons are oval. Yet they still
loosen. We fix them by temporarily sealing the undersides of the top block
and tops of the posts with tub and tile caulking, and pouring thin epoxy
into the gaps in the joints, then repeating the process at the pedal box.
ends. This could easily be avoided if the lyres were made like some European
pianos  from the 1900's or earlier, where the posts were dovetailed into the
front edge of the top blocks and pedal boxes. These never seem to be a
problem, at least not in those I have seen, such as old Broadwoods. Makimg
dovetail joints with modern specialized machines should be no problem, and
no more costly than the present inferior though universally accepted design.
Even if these joints did loosen, re-glueing would be very straightforward
and workmanlike. (The dovetails were always reinforced with a screw as
well).

All the best, Ted----- Original Message -----
From: "Susan Kline" <sckline@attbi.com>
To: <caut@ptg.org>
Sent: Wednesday, April 03, 2002 10:49 AM
Subject: Re: Lyre braces


> At 11:04 AM 4/3/2002 -0500, you wrote:
> >I do very much realize that a turnbuckle would look just hideous, but the
> >idea of being able to tighten these is very appealing.
>
> There are systems, such as Ted's, which are not hideous. Of course the
> upper end is used. I saw one Steinway M which used a long hexagonal
> nut on a piece of darkened threaded rod in place of the wooden square
> piece at the top. It was very easy to adjust.
>
> However, this piano illustrated a danger of adjustable lyre braces --
> One brace must have been overtightened at some point, because the glue
joint
> between the right post and the (lovely old 1918 S&S) lyre box had failed.
> Since I saw (and mended) this, I adjust braces to just touch, not exert
> pressure.
>
> Susan Kline
>