Regulating With Metrics

[mccleskey112 at bellsouth.net]

Just think, no more Chickering Quarter grand. Now it would be 6mm or .25 Chickering grand. 
Gerald McC
  ----- Original Message ----- 
  From: Dean May 
  To: 'Pianotech List' 
  Sent: Tuesday, February 05, 2008 8:07 AM
  Subject: RE: Regulating With Metrics


  A hearty amen. When going through engineering school we primarily used metrics and even when I worked in design in industry.  It sure did make the calculations easier. 

   

  Here's a rough chart for you:

   

  1" = 25 mm (25.4)

  3/4 = 19 (19.1)

  1/2 = 13 (12.7)

  1/4 = 6 (6.35)

  1/8 = 3 (3.175)

  1/16 = about 1.5 (1.6)

  1/32 = about 1 (.8)

   

  Dean

  Dean May             cell 812.239.3359 

  PianoRebuilders.com   812.235.5272 

  Terre Haute IN  47802

   


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  From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Jurgen Goering
  Sent: Monday, February 04, 2008 11:53 PM
  To: pianotech at ptg.org
  Subject: Re: Regulating Without Specs

   

  At the risk of opening a large can of worms and an even larger debate, I think this is perfect example of why going metric (like Dale Erwin demonstrated) is such an elegant mode of transport through exercises such as these. Mixing fractions with decimal inches may work in this prepped example, but the numbers are hardly ever so fortuitous. I heartily suggest to all technicians to immerse themselves in millimeters, stop converting to inches, buy metric rulers, calipers and whatever other measuring tools they need and discover the brilliant ease of working in that system.
  ducking for cover...
  Jurgen Goering


  On Feb 4, 2008, at 19:20, pianotech-request at ptg.org wrote:

  snip...
  Let's just say you want something typical like a 3/8" key dip, 1/8" letoff, and .050" aftertouch.  (Later I'll show the equations for solving for different variables)   Given the 3/8" key dip (.375") and the .050" aftertouch, we subtract aftertouch from key dip and know then that we have .325" of useable key dip to move the hammer.  How far will it move?  It will move 5xs the amount of keydip.  5 x .325" = 1.625".  But that's not the hammer blow distance, because we haven't accounted for letoff.  If we want 1/8" (.125") letoff, we need to ADD that to the hammer travel of 1.625", so the blow distance is then 1.75", or 1 ¾".
   ...snip...
  OK, Lemme know whatcha think!


     
    John Dorr, RPT 
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