<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html> David, You guessed correctly.  The pins I have are Diamond brand made by Klinke to my specs.  The actual specs are1/0 or 2/0 (7.00mm. or 7.15mm.) from the top to 4mm. below the becket and 3.5/0 (7.30mm.) the rest of the way. You're right that they have no bearing (no pun intended) on the question of pin contact with the plate.  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? 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.  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. 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. 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. 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. 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. 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. Oh, yes.  They cost about 30% more than regular Diamond pins. Paul Larudee David Skolnik wrote: <blockquote TYPE=CITE> Paul, Joe- 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: 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. 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). Share your thought, and how much did you pay for them (the pins, that is)? David Skolnik       At 09:23 AM 05/14/2001 -0700, you wrote: <blockquote type=cite class=cite cite>Paul, 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.=.265"). Hope this clarifies for you. Regards, Joe Garrett, R.P.T. <blockquote type=cite class=cite cite>----- Original Message ----- From: <a href="mailto:larudee@pacbell.net">larudee@pacbell.net</a> To: <a href="mailto:pianotech@ptg.org">pianotech@ptg.org</a> Sent: Monday, May 14, 2001 7:40 AM Subject: Re: Ditch the tuning pin bushings Del & David, 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.) Paul Larudee     David Skolnik wrote: <blockquote type=cite class=cite cite> At 11:22 PM 05/13/2001 -0700, you wrote:   <blockquote type=cite class=cite cite>Another thought though; someone mentioned to me the problem of restringing with oversize pins -- something I'd not really thought about since we don't do this. Del</blockquote> Del- Could you make clear what size pin qualifies as "oversized", assuming that 2/0 was the original?  Thanks. David Skolnik    </blockquote> </blockquote> </blockquote> </blockquote> </html>