Pin Block Torque

[DGPEAKE@AOL.COM]

In a message dated 10/03/2000 4:51:17 PM Pacific Daylight Time, 
mfarrel2@tampabay.rr.com writes:

<< Hello Piano People. I am drilling my first real pinblock (don't ask what
 that means). The material is standard supply house hard maple multilaminate
 (I think about 9 to 12 ply or so). Pins are size 2/0, and mic out @ 0.2865
 inches. Drill size is 0.271 inches. This combination is giving me between 90
 and 100 inch-pounds of torque on the pins when driven into the bare,
 uninstalled pinblock, to their final installed height (the amount of pin
 that will be in block when block is installed in plate). This is also after
 one full turn of the torque wrench (simulating taking up tension on new
 string).
 
 I have two questions. Will I find the torque different when I have
 everything in piano - a turn or two on pins when installing new strings
 (ultimately decreasing torque) - and after plate bushings are installed
 (this plate is a full 1/2 -inch thick) (ultimately increasing torque). Do
 these two cancel out, or what does one normally experience in differences
 between torque testing in the bare pinblock and after final installation?
 And the second question is: waddaya think of the 90 to 100 inch-pounds of
 torque. I know this is great for tuning, but do I want more - like maybe up
 to 150 - just for longevity? This is a cheap little grand that will be tuned
 in the future at most once a year .......etc. Thanks for good input.  :-)
 
 Terry Farrell
 Piano Tuning & Service
 Tampa, Florida
 mfarrel2@tampabay.rr.com
 
 
  >>

I prefer to bore the pinblock between 125 and 150 inch pounds. The torque 
will go down after a while. How long is difficult to predict. 

Dave Peake, RPT
Portland Chapter
Oregon City, OR
www.davespianoworks.locality.com