<font color='navy' size='2' face='Comic Sans MS, sans-serif'><font color="#000080" face="Comic Sans MS, sans-serif" size="2">Last Sat. Laroy Edwards and I taught a joint class in my shop to members of several local chapters in the region. Great fun and the Head piano Meister at 84 yrs young; ... was on his game.</font> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2">  I had the pleasure of sitting in his "<u>after touch class".</u> where He clearly defined after touch. </font></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2"><br> </font></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2">  Short story is that after touch begins as soon as the jack escapes the knuckle. How far it moves past that is the real after touch number/distance/feel. One limiting factor to jack movement and hence after touch is determined by the total length of the repetition lever slot. The jack cannot move beyond the rep.lever slot stop with out the jack tender binding and then breaking off. Bummer. Ca glue please anybody.</font></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2"><br> </font></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2">  Another limiting factor is that the jack must escape enough that it DOES NOT have </font><font color="#000080" face="Comic Sans MS, sans-serif">opportunity</font><font color="#000080" face="Comic Sans MS, sans-serif" size="2"> to dance with the knuckle and do the mister booble head thing. With repetition in mind the farther the jack escapes the farther it has to travel back, and we all know this of course will slow repetition.</font></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2"> </font></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2">   So within those  parameters in mind some variability is allowed/acceptable based on subjective feel. I'll leave it at that for now. Using Davids cardboard method to just sense jack escapement is quite good I think.  Many techs that use this method state a preference like..... "I like .040....050 ...060. cardboard placed on top of the front punching as there sensory gauge" </font></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2"> So these are small parameters to be sure but we and our pianists clients live in the realm of the subjective. Some like dip/key travel deep some like it so short that mister bobble head can almost dance and these folks, oddly enough....have learned to control it.</font></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2"> </font></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2"> </font><span style="color: rgb(0, 0, 128); font-family: 'Comic Sans MS', sans-serif; font-size: small; ">Dip.</span></div> <div><span style="color: rgb(0, 0, 128); font-family: 'Comic Sans MS', sans-serif; font-size: small; ">  This Sticky wicket wording to me </span><span style="color: rgb(0, 0, 128); font-family: 'Comic Sans MS', sans-serif; font-size: small; ">always</span><span style="color: rgb(0, 0, 128); font-family: 'Comic Sans MS', sans-serif; font-size: small; "> needs clarification</span></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2">   So this means to me overall key travel top to bottom. How we measure it will be confusing unless we speak specifically how we do that. In setting up any action regulation parameters I am  looking for roughly those numbers David suggests. ie. 45mm or 1 3/4 blow....Let off at approx. .050/1.3mm,  </font></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2">(I like it close.) and a .390 dip.  I measure that just in front of the key pin & right under where the finger touches the key much of the time with a direct measurement gauge. (the Erwin dip gauge)</font></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2"> ( see picture.)  Now I realize that the key travel depth can vary given the wide variance of action ratios, typically 5 to 6.5, but actions that fall within what we all refer to as normal compliance, fall into these numbers routinely. So its at least a starting point when looking for parameters.</font></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2">Other folks measure at the very front of the key with a metric ruler. Whatever works</font></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2"><br> </font></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2"> Another consideration is that the standard green front rail punching available can easily squish .035. </font></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2">That seems like a lot don't ya think? This is not a promotional but the fairly new Cresendo punching compress a very predictable .015. So,.... over all key travel can be set very precisely. Some don't like the feel but that's another story. So overall dip/key travel set from a basically static method changes quite variably under different dynamic ranges/key pressures with the green squishy punching. </font></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2"> So now;... what is the dip really?</font></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2">  I just wanted to clarify some other reasons why Jim might be a bit confused since I was thinking about it lately.</font></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2">  </font></div> <div><font color="#000080" face="Comic Sans MS, sans-serif" size="2"><br> </font><br> <div style="color: navy; font-family: 'Comic Sans MS', sans-serif; font-size: 10pt; clear: both; "><font size="1" color="royalblue"><b><font face="Georgia, Times New Roman, Times, Serif"><font color="black"><font color="mediumblue" face="Comic Sans MS, sans-serif">Dale Erwin R.P.T.<br> <font color="green">Erwin's Piano Restoration Inc.</font><br> </font></font></font></b></font><font color="darkgreen"><span style="font-style: italic;"><b><font size="1"><font size="1" color="black"><font color="blueviolet"><font color="black"> <font color="black" face="Comic Sans MS, sans-serif">Mason & Hamlin</font><font face="Comic Sans MS, sans-serif">/Steinway/</font><font color="black" face="Comic Sans MS, sans-serif">U.S. pianos</font><font face="Comic Sans MS, sans-serif"><br> </font></font></font></font><font size="1" color="cornflowerblue" face="Comic Sans MS, sans-serif">www.Erwinspiano.com</font><font size="1"><br> </font><font size="1" color="crimson" face="Comic Sans MS, sans-serif">Phone: 209-577-8397</font><br> <font color="darkgreen"></font></font></b></span></font><tt><tt><font color="darkgreen"><br>  </font><br>   <font size="2"></font></tt></tt><br> <br> </div> <br> <br> <div style="color: black; font-family: arial, helvetica; font-size: 10pt; ">-----Original Message-----<br> From: David Love <davidlovepianos@comcast.net><br> To: pianotech <pianotech@ptg.org><br> Sent: Sun, Aug 26, 2012 11:51 am<br> Subject: Re: [pianotech] action ratio<br> <br> <div id="AOLMsgPart_0_cea1fe86-c92b-4ac4-ae2e-1a399da24379" style="margin: 0px;font-family: Tahoma, Verdana, Arial, Sans-Serif;font-size: 12px;color: #000;background-color: #fff;"> <pre style="font-size: 9pt;"><tt>I don't quite think it's apples to oranges because for any given action ratio there will be at least a limitation to the regulation specs or the dip/blow relationship. I agree that the formula is confusing but I don't think it has to be. Determining when let-off and aftertouch actually start seems to be the problem. Once established, however, I see no reason why a default setting for the sake of this formula can't be used. Moreover, I find that it's the aftertouch part that is confusing. As far as the formula goes, my own experience suggests that a let-off number of 1.5 and an aftertouch number of 2.5 produces regulation specs that I expect to find with a given action ratio. The problem seems to be defining exactly what aftertouch is, at least as it pertains to this formula. Blow, dip and let-off are more easily defined. David Love <a href="http://www.davidlovepianos.com" target="_blank">www.davidlovepianos.com</a> -----Original Message----- From: <a href="mailto:pianotech-bounces@ptg.org">pianotech-bounces@ptg.org</a> [<a href="mailto:pianotech-bounces@ptg.org?">mailto:pianotech-bounces@ptg.org</a>] On Behalf Of Jim Ialeggio Sent: Sunday, August 26, 2012 8:32 AM To: <a href="mailto:pianotech@ptg.org">pianotech@ptg.org</a> Subject: [pianotech] action ratio David L said: <The question at hand has to do with what exactly is the after touch spec that's used to make the formula ratio by product of the levers equal to the blow/dip ratio as given. (and) <But when I input those numbers in this calculator, as you can see, then by that formula a 5.75 AR with 45 mm of blow distance should regulate with 8.6 mm of dip. This illustrates the confusion I find in these formulas, if they are to be used from a design perspective rather than as a ballpark reactive position in the field. I feel the (blow distance-let off)/key dip-aftertouch) part of the equation, when compared to the lever arms part of the equation is apples to oranges. The lever arm side of the equation looks at the lever arms as the product of fixed ratios. However, the blow distance ratio does not look at blow distance and key dip as fixed ratios, but rather inputs arbitrary letoff/aftertouch as necessary to make that side of the equation match the fixed ratio side, as I think you've noted, David. Or seen another way, if you are going to use the blow distance side of the equation as given, then the lever arm side must take into consideration the whip's changing leverage and the shank's changing leverage during letoff. This changing leverage presents difficulties that would require computing complexities way beyond simple algebra. Taken in this light, your shy 8.6mm dip could be more a result of blow being quantified artificially. According to the fixed leverages, blow is not the distance between hammer at rest and the strings minus letoff, but rather (Full unimpeded travel of the hammer with out any letoff or strings) = Action ratio*(key dip-aftertouch). By the way, my comment here is not that this formula doesn't empirically work, but rather that the thinking behind it seems to be selective and thus confusing, at least to me. Jim Ialeggio -- Jim Ialeggio <a href="mailto:jim@grandpianosolutions.com">jim@grandpianosolutions.com</a> 978 425-9026 Shirley Center, MA </tt></pre> </div>  </div> </div> </font>