I 'spec someone does ...

[Mark Potter]

Michael Magness <IFixPianos at yahoo.com> wrote:    I don't CA every loose pin I run across, most times driving them about an 1/8 of an inch will tighten them up unless they're REALLY loose. Try it you might save a little on CA.
  I still stand by the rest, I would drive them before I would CA them. Drive them now and CA in 10 or 15 years when they need that!
   
  Mike 
  
To say I am reluctant to join in this fray is a major understatement, but...  in the 30 years I have been in this business I have always felt like driving pins in deeper was pure folly, just enough to get you out the door.  
   
  Follow me here...OK, the threaded part of the pin, in the longest pin available (2 1/2"), is in the pinblock 1 7/8", right?  And now it's loose.  Driving the pin in 1/8" more is gonna cure something for any length of time? Seems ridiculous, (sorry!).  So, you drive it, and it is now still loose in the top 1 7/8", and tight in the lower 1/8", right?  A few observations: 
   
  1) what makes you think that 1/8" is gonna last when 1 7/8 didn't?; 
  2) the feel of the pin when tuning is lousy; 
  3) if there is a crack or delamination, the condition worsens when driving, and unless you have access to imaging equipment I am not aware of existing there is no way for you to know this in advance; 
  4) given the above worries, it is also true that to do the job correctly you must remove the action and brace the pinblock from below before driving.  This translates into expense, (needless, IMO) 
   
  Compare this to CA:
   
  1) it treats the problem where it lies= in the part of the pin that makes contact with the block; 
  2) it appears to be long lasting at a much greater frequency than driving; 
  3) no potential damage is done to the block; 
  4) it is fast, easy, and cheap. Action remains in place.
   
  I don't see the compelling argument for driving here.
   
  Mark Potter
   
    
-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://www.moypiano.com/ptg/pianotech.php/attachments/20070926/cbc3d3e9/attachment.html