Tensioned hammers and "the staple"

[John Delacour]

At 20:06 26/09/01 -0700, Delwin D Fandrich wrote:


>  Is that why the staples in the last set of Abel hammers I used has a 
> noticable gap between the head of the staple and the felt?

Or why I have a Steinway action beside me with machine-stapled Abel hammers 
where 90% of the heads have flipped wide open pulling the staples with them 
after a few months in a damp place where 90 year old hammers are intact?

>The staple probably had some tonal effect back in the days when there was 
>still some resiliency in hammer felt. It's been some time since we've seen 
>much of that in production hammers.
>
>I regularly pull them in the upper third to half of a typical hammer set 
>so I can remove some of the excess felt most hammers come with.

I think the distinction has to be made between the useless staples, which 
are U-shaped wires driven into the moulding by machine and T-rivets which 
are pushed through a pre-drilled hole and folded over, like the older 
twisted wire method, either of which is superior if anything is needed at 
all.  However plastic the modern felt may be, it has some resiliency.

When I plane the taper on Imadegawa hammers, which are T-riveted, I 
occasionally have to fold up the tails of the rivet to avoid damaging the 
plane, but I leave them in except, according to need, in the higher treble.

It seems to me that any stretching effect of the rivets on the outer layer 
of the felt (however resilient) would be annihilated before it reached a 
few millimetres up the hammer and they are unlikely to have any tonal effect.

JD