pianotech-digest V2000 #984

[Walter Gramza]

Hi Ladies And Gentlemen:
If you are lucky enough to make or brrow a zapper formerly designed by
Francis Mehaffey which consists of a 12volt transformer and a set of probes
of which you would put onto the frozen letoff screws and the low heat would
eventually loosen the frozen letoff screws.  I have used this method a few
times very sucessfully.  If you need more information let me know.

Walter GramzaAt 09:30 AM 11/12/00 -0800, you wrote:
>What is this?  A piano question?  ;-]
>
>I'd try Protek.  It won't hurt anything.  If you can get at the broken
>screws...prop up the rail and tap them out with a thin punch. CA in a shim
>if needed and install new ones.
>
>David I.
>
>> -----Original Message-----
>> From: owner-pianotech@ptg.org [mailto:owner-pianotech@ptg.org]On Behalf
>> Of Dave Nereson
>> Sent: Sunday, November 12, 2000 8:55 AM
>> To: pianotech@ptg.org
>> Subject: Re: pianotech-digest V2000 #984
>>
>>
>> Does anyone know how to loosen up "frozen" (seized-up) regulating
>> screws --
>> in this case, let-off screws.  This is in a Baldwin studio, only 20 years
>> old or so.  I tried turning them carefully and the eyelets would
>> break off.
>> So I had to take off the button, grab the other end of the screw with a
>> vise-grips and turn out the remainder of the screw.  But in some
>> cases, that
>> would break off also, leaving only that portion of the screw that's in the
>> wood, and nothing left to grab.  So I tried heating them all with a torch,
>> thinking the expanding metal would also expand the hole in the wood, then
>> when they cooled, they might turn easier, but no dice.  They still break
>> off.  And they're not even rusty.  I hate to put any type of oil or liquid
>> lube, thinking that would expand the wood cells, making the let-off screws
>> even tighter.  How to get the remainder of the screw out of the wood?  (I
>> can do it by carving away enough wood to let me grab some screw with the
>> visegrips, but hate to butcher the rail).  Can ya buy a new let-off rail
>> from Baldwin (it's the common studio model that's in many many schools)?
>>
>>
>