[Michael Spreeman]

Oh, here's a photo showing the counter bore numbers. I'm not sure it will come out; these are made by Union Butterfield and I have two different sizes for different plate applications:  a 7/16th" # 6210037 and a 13/32" # 6210036.  
 
As a quick note of clarification:  the V-bar insert can be used to change the string height in the treble.  
 
This modification can also work well when rebuilding a piano which has a large variance of string heights from tenor to treble where the pinblock wasn't installed properly at the factory, or by another tech, and one is not replacing the block.  Obviously, the best solution is to put in a new block or reposition the exiting block in order to return the string heights to factory spec. But changing the location of the block in a piano which has it mortised and doweled into the stretcher, inner rim, and side of the case is almost impossible, and the block has to be cut out anyway, so why not just put in a new one.
 
I'm curious about how many rebuilders take into consideration string height parameters when installing new blocks vs simply duplicating what was there to begin with?
                Michael C. Spreeman http://www.spreemanpianoinnovations.com


From: m_spreeman at hotmail.comTo: pianotech at ptg.orgSubject: Date: Fri, 25 May 2007 15:02:20 -0600


Terry, There's been ample quality input about your agraffe dilemma.  But if you are determined to make corrections by changing string heights, I thought I'd offer a coupld of alternatives. You could consider removing material from the plate instead of the agraffes. The attached photo shows two counter bores with centering pins which I use for leveling agraffes. The centering pin keeps the counter bore perfectly centered in the agraffe hole. You could also consider installing a V-bar insert which would require meticulous recording of the original V-bar location, grinding the original V-bar down to the exact diameter of a new V-bar rod, and then shaping and attaching the new V-bar to the plate.  Each of these steps opens the door to extensive conversation and controversy on the list: how to measure and document the location of the original V-bar, grinding the plate (are you SERIOUS!!), what type of material to use for the new V-bar, how to affix the new V-bar, and on and on.  I thought I'd throw it out here to shake things up, rattle a few cages,  and give everyone something to debate for bit. BTW,, Major Kudos to Terry for the exquisite manufacturing of the laminated bridge bodies shown in the May Journal article about the Ravenscroft!  That's right,, both of those bridge bodies were "hand crafted" by non-other than our wonderful Terry!
                Michael C. Spreeman http://www.spreemanpianoinnovations.com

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