String termination devices

[Phillip L Ford]

I had an idea similar to this, but the central portion of the
device was like an agraffe, an upright piece with holes
through it. The string passes over a bearing area, as with
your device, deflects down and through the hole in the
'agraffe' and back up over the second bearing area. I had
thought of screwing it into the bridge. The problems are
that the holes would be difficult to put in by machining,
although with casting or powder metal process would be OK,
and that screwing them in gives you some alignment problems,
just like with agraffes on the plate.  Your device addresses
these problems.  I do also worry that the separate 'bearing
rod' held in place by string pressure (if I understand your
sketch correctly) might buzz.  Give me a couple of days on
the Patent Numbers.

Phil
---
Phillip Ford
Piano Service & Restoration
1777 Yosemite Ave - 215
San Francisco, CA  94124


On Thu, 8 Nov 2001 10:39:37   
 Delwin D Fandrich wrote:
>
>----- Original Message -----
>From: "Phillip L Ford" <fordpiano@lycos.com>
>To: <pianotech@ptg.org>
>Sent: November 08, 2001 5:59 PM
>Subject: Re: String termination devices
>
>
>> Del,
>> Thanks.  I could see the sketch, but for some reason my computer wouldn't
>> let me print it out, so it's now become a second hand sketch in my own
>> hand.
>
>Well, I'm just glad it made it to you intact. Ain't e.mail wonderful!
>
>
>>
>> This is very interesting and somewhat similar to a couple of things
>> I've seen in old patents.
>
>Don't suppose you have a couple of patent numbers handy?
>
>
>>
>> I like the idea that there is no net force on the
>> bridge (assuming no down bearing) - no twisting as in present arrangement.
>> Do you think the weight of these terminations would be an issue at the top
>> end of the scale?
>
>Shouldn't be. You're also taking a certain amount of wood (typically maple)
>off of the top of the bridge. There might be a bit of extra mass, but it
>won't be much. If it proved to be a problem you could alway shave a bit more
>off the sides of the bridge body, but I really don't think it would be
>necessary.
>
>The only real concern I had was the possibility of them buzzing or rattling
>sometime in the future. I looked into using CA adhesive to bond them to the
>surface of the bridge but was advised by the CA manufacturers that CA
>wouldn't be practical for this use. They couldn't assure me of its long-term
>bond strength and they had concerns about its standing up under continued
>vibrations. I'm not sure this would be necessary anyway, string bearing
>should be adequate to hold it tight against the bridge body along with the
>one screw.
>
>I still like the idea and will try it again as soon as I figure out a way to
>have them made economically. There are a couple of powdered metal processes
>that look promising.
>
>Del
>
>
>
>