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Paul wrote
Rather, I was picking up on Del's comment about never using oversize =
pins and the question of open vs. closed blocks. He's not the only one =
who refuses to use oversize pins, and why not?=20
I can think of two good reasons. Presumably we want tuning pins to be =
as narrow in diameter as possible because a) the amount of leverage =
(torque) exerted by the string tension increases with each increase in =
diameter (radius) and b) the amount of string moved per unit of =
rotational movement also increases accordingly. Smaller caliber pins =
are therefore easier for the technician to turn (and less easy for the =
string tension to turn), and permit smaller, more precise string =
movements, all other factors being equal.=20
Paul ,the other reason is that when Del Or I or any rebuilder says that =
we don't install oversize pins the third answer or consideration is that =
usually we're putting in an entire new belly system and we want and =
beleive that good practice dictates a new block.Afterall our idea is =
that we're starting the life of the piano over.=20
Now I see nothing wrong with repinning from a no.2 to a 3 pin in an =
original well preserved block andI do that on occasion with very good =
results.But no.3 are my limit.
Best, Dale Erwin
The fact that they are less easy for the string tension to turn also =
makes the tension more stable. I don't think I'm saying anything new =
here, but if there are other reasons not to use oversize pins (in =
principle, not in practice), I would be interested to know.=20
On the other hand, there are also reasons not to use pins that are too =
narrow. Even if pins were made of a material stronger than they are, we =
would not want them to be so narrow that they would slice through the =
pin block or deform the holes. We need enough surface area so that the =
integrity of the block is not in jeopardy. Another consideration is =
flexion. Narrower pins will flex more than wider ones. I agree that =
some flex is necessary, but generally speaking, I consider this =
something to keep to a minimum. I would rather maximize the ability to =
change tension in the smallest possible increments through changes in =
pin setting (rotational movement in the block) than to depend upon =
flagpoling to modify pitch in small amounts.=20
On the other hand, flagpoling becomes more feasible when string geometry =
is designed in conjuction with it. When there is more friction at the =
bearing points, flagpoling becomes more necessary to overcome it, and at =
the same time the friction helps to prevent changes in tension that =
might otherwise result from a pin that flexes too easily. However, I =
think that this is a second best approach, and the best is still to have =
a design that permits finer pin setting and depends less upon =
flagpoling.=20
One of the advantages of open face pin blocks is that they achieve =
exactly that. The force of the string tension is much closer to the =
fulcrum, which makes flagpoling less of a factor. This permits the use =
of narrower pins, which is presumably why 1/0 pins are standard in this =
design. On the other hand, 2/0 pins are pretty much standard in closed =
blocks, where 1/0 would generally be too flexible. Unfortunately, this =
distances us from the advantages of narrower pins.=20
Obviously, oversize pins remove us even farther. That is why I designed =
my pins. They are oversize where they need to be, but the same size as =
standard pins at the coils, and therefore with the same torque =
characteristics as standard pins. It is even possible to reduce from a =
size 2/0 to a 1/0 without putting in a new pin block.=20
Although my pins are designed for repinning, whether as single pins, =
sets of bass strings or an entire piano, the same principle can be =
applied to new instruments, allowing the size at the string coils to be =
divorced from the size that goes into the block. This gives more =
options with regard to torque, flexibility, contact area in the block, =
etc.=20
Oh, yes. They cost about 30% more than regular Diamond pins.=20
Paul Larudee=20
David Skolnik wrote:=20
Paul, Joe-=20
Joe, it sounds to me as though Paul is describing something different. =
Paul, I guess we could find out your special reason directly from you, =
or by getting in touch with one of two Davids. I'm not clear on the =
engineering, however, for starts the implication here is that the =
benefit of the smaller pin resides in its smaller string coils rather =
than the total surface area in contact with the block. I'm not clear as =
to why you would want additional stiffness in that area of the pin =
unless you think the pins are being pulled forward due to insufficient =
surface area (part of pin in the block itself) or due to excessive =
flexing. If you are talking about repinning with these, two problems =
come to mind:=20
1) Given the current discussion of pins already in contact with the =
plate, it seems to me you would have a bit of a problem installing them, =
unless you were to drive them in from the bottom of the block. That =
would certainly be something to write about.=20
2) As a few on this topic have mentioned, and with whom I agree, a =
small degree of flex is a useful fine tuning tool. It would seem that, =
by stiffening the pin up to the coils, and then reducing the size at the =
top, you would be directing the flex force to one, already weakened area =
of the pin (string hole).=20
Share your thought, and how much did you pay for them (the pins, that =
is)?=20
David Skolnik=20
=20
=20
=20
At 09:23 AM 05/14/2001 -0700, you wrote:=20
Paul,=20
Many years ago, Piano Manufacturers actually used a tuning pin like =
you describe. It is called a tapered tuning pin. They had many =
advantages. One of which is, slight tapping of one that is considered =
loose, fixed the problem. These pins were approx. #1 pin size at the =
bottom and approx. 3/0 at the top. (that is not a typo: #1 tuning pin =
dia.=3D.265"). Hope this clarifies for you.=20
Regards,=20
Joe Garrett, R.P.T.=20
----- Original Message -----=20
From: larudee@pacbell.net=20
To: pianotech@ptg.org=20
Sent: Monday, May 14, 2001 7:40 AM=20
Subject: Re: Ditch the tuning pin bushings=20
Del & David,=20
What about a tuning pin that is oversize from just under the coils =
down and size 1/0 or 2/0 from there up? That would give added stiffness =
to the pin in the portion that passes through the webbing without =
sacrificing the better torque and smaller string coils that you get with =
standard size pins. It also allows reuse of the old pin block (if it is =
in good condition) while still retaining the benefits of standard size =
pins. (David Love and David Ilvedson know that I have a special reason =
for asking this question.)=20
Paul Larudee=20
=20
=20
David Skolnik wrote:=20
At 11:22 PM 05/13/2001 -0700, you wrote:=20
=20
Another thought though; someone mentioned to me the problem of =
restringing=20
with oversize pins -- something I'd not really thought about =
since we don't=20
do this.=20
Del
Del-=20
Could you make clear what size pin qualifies as "oversized", =
assuming that 2/0 was the original? Thanks.=20
David Skolnik=20
=20
=20
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