brass rail loose hammers

[Richard Moody]

I am having a similar problem with a brass rail flange piano.  What is
happening in my case is the tongue of the rail is cracking : ((   . 
Sometimes this is not apparent, but with the butt removed, and some
pressure applied to the tongue with a screw driver and light tapping will
break the tongue off.  This indicates a weak tongue, that was ready to
break, and made the "hammers seem loose" ie they move from side to side
more than they should.   Where the tongue is solid, it will not give in
this test.  I don't know what brand of new butts you used, but they can be
pinned loose from the supply  house.  Take a butt that is solid and put it
in the brass rail where one is loose.  If that solid butt is still solid,
the problem then has to be in the plate or the rail. 
	Now maybe you are lucky and the plates are weak. Usually on close
examination of these, out of the piano of course, will reveal a slight
crack. However it is best to put the plate in a pliers and try to "bend"
it in the bench top.  If weak it will break. It is then a simple matter to
replace those plates.  
	A last hope is that the screws are too small or the screw holes too
large.  Given the quality from supply houses today, of brass rail
replacement screws plates and makeshift tongues, the tolerences in these
leaves much to be desired.  You have to "select" like you do in the lumber
yard, for good parts. On the piano I am working on, I have yet to find a
replacement tongue that I did not have to file with a "needle" file.  
	Another test is to put the action on an action cradle, tilt it so the
hammer shanks are parallel to the bench, then drop the  hammers against
the rail and listen for "singing" flanges.   If you are familiar with this
test, it can be done in the piano for a pleminary indication.  If they
sing, they are weak either in the bushing or the rail, ie the plate or
tongue. To these "singing" hammers, apply the tests mentioed above.  

Richard Moody.  
----------
> From: James Dally <jdally@knox.net>
> To: pianotech@ptg.org
> Subject: 
> Date: Saturday, June 13, 1998 12:09 AM
> 
> I installed new butts and hammers on a Kroehler upright.  I have checked
> the brass rail and the brass butts where the screw goes in.  This is the
> type where the screw goes through the rail and then the brass butt
receives
> the threaded screw.  The butts have been replaced where hammers have
> loosened but the problem continues.  When it seems I have solved the
> problem, another hammer loosens.  As near as I can tell the rail is not
> cracked.  If anyone has had experience with this problem I will
certainly
> appreciate advice.  Jim Dally