Baldwin hitch pin replacement?

[Michiel van Loon]

Thanx Del,
This explains a lot to me.
We don't se many Baldwins here in Europe, the only ones I've seen were on
the Frankfurter Musik Messe.
Is 10mm thickness of the hitchpin panel thick enough? I'm talking about a
Grotrian Steinweg plate here.

Michiel van Loon
Meppel
the Netherlands

-----Oorspronkelijk bericht-----
Van: Delwin D Fandrich <pianobuilders@olynet.com>
Aan: pianotech@ptg.org <pianotech@ptg.org>
Datum: dinsdag 17 augustus 1999 17:24
Onderwerp: Re: Baldwin hitch pin replacement?


>
>----- Original Message -----
>From: Michiel van Loon <mvanloon@xs4all.nl>
>To: <pianotech@ptg.org>
>Sent: Tuesday, August 17, 1999 10:55 AM
>Subject: Re: Baldwin hitch pin replacement?
>
>
>
>Del or anybody else,
>
>Could you please explain to me a little more precise what kind of pins can
>be used as verical hitchpins?
>I understand that they should be 4mm in diameter. But the word tension pin
>does mean anything to this dumb Dutchman. What are they? What kind of steel
>is preferred for those pins?
>And how are they fixed in the plate? Just drill a hole a bit smaller , say
>3.9mm and drive them in?
>
>Michiel
>
>-------------------------------------
>
>Michiel,
>
>Go to http://www.preciseprod.com/whatis.htm and read about the "slotted
>spring pin."
>
>They are installed such that about 12 to 15 mm of the pin extends above the
>plate surface.  The holes are usually drilled at about a 1º to a 2º back
>angle.  The string is passed around the pin an string tension holds it in
>place.  String bearing can be "adjusted" by moving the string up or down on
>the pin.
>
>I prefer to design the bridge such that proper string bearing can be
>achieved with the string about 5 mm off of the plate surface.  This does
not
>leave much room for "adjustment," but then I don't think of this as a way
to
>get around sloppy work.  In fact, my favorite hitch pin is one called a
>"Groov-loc" Type IV (I think -- it has been a while since I have had to
>order.  10,000 pins goes a long way!).  It is a solid pin with an annular
>groove about 2 or 3 mm down from one end.  The other end is staked with 3
>sharp v-grooves running parallel with the pin.  It is these grooves that
>hold the pin in place.  The advantage is that the string is held precisely
>where I want it to be.  No one is going to be "adjusting" bearing on the
>piano indiscriminately.  (Yes, it does happen.  Yes, soundboards have been
>damaged.)  With these pins, the string can be lowered -- carefully! -- by
>tapping the pin further into the plate.  It cannot be raised without
>removing the plate.  This is the type of pin I used in the Walter 190
design
>(among others).  I do not know if they are still using it or not.  I hope
>so.
>
>The strings should never be very high off of the plate surface with any of
>these designs.  The stresses on the plate can become extremely high.
>Baldwin plates are made thicker through the hitchpin panel to compensate.
>Others, obviously are not.  Proceed at your own risk.  Even with the
heavier
>Baldwin plate I would be cautous about placing the strings much higher than
>6 or 8 mm.  Yes, I know.  Baldwin workers often place them higher than
this.
>I would rather spend a bit of extra time and fit the plate a bit closer.
>The higher the strings ride on the pin, the more potentially unstable the
>piano will be.  Especially if it has to be pitch-raised.
>
>Del
>Delwin D Fandrich
>Piano Designer & Builder
>Hoquiam, Washington  USA
>E.mail:  pianobuilders@olynet.com
>Web Site:  http://pianobuilders.olynet.com/
>
>
>
>
>