I've never tried this, but those numbers are interesting and raise some questions for me, especially the UW/DW relationship, where the UW is reduced by almost as much as the DW. Would you ascribe the effect strictly to spring action when the front of the punching is first compressed and then released? If so, how much difference would thick vs. thin punchings make? How much of the weight difference (in the case of the original whole punching) goes away as the punchings are compressed in front through use? (if it changes much at all, leveling the keys and replacing the punchings in a different orientation would seem to produce random key-weight changes). Would the effect be mitigated by beveling the balance rail at the point where the pin enters the rail (ignoring for the moment the problem of likewise beveling the rail under the sharps)? These all would seem to be random variables in the key-weight equation that I've never considered before and make me wonder if some of the weigh-offs that I've done could have been avoided. On a related note, has anyone retrofitted a standard keyboard with S&S bearings? How much difference did it make and how much trouble was it? Thanks in advance to anyone who can answer any of these. Kerry Kean www.ohiopianotuner.com <http://www.ohiopianotuner.com/> _____ From: Mark Dierauf [mailto:pianotech at nhpianos.com] Sent: Friday, January 08, 2010 11:37 AM To: pianotech at ptg.org Subject: Re: [pianotech] PUNCHING TRICK ??? I seem to consistently get more like 5 grams from the half punching trick (that is, tacking the punchings to the keys with a drop of glue just behind the balance hole and slicing them in half at the hole when the glue has dried. Here are the before and after numbers from an S&S B action I currently have on the bench. As can be seen in the bottom row, I've saved and average of 6.1 grams of downweight and nearly 6 grams of balance weight. This piano had new Renner parts installed probably 40 years ago and has always been a beast to play. I'm storing it long term and am just trying to make it more playable without spending any more of my uncompensated time than possible. SW's are all over the place and FW's are near maximum values. Before After Note DW UW BW DW UW BW 1 57 32 44.5 52 27 39.5 2 62 32 47 55 26 40.5 9 59 30 44.5 52 24 38 10 60 33 46.5 51 25 38 16 61 32 46.5 57 25 41 17 64 35 49.5 53 28 40.5 20 55 29 42 50 25 37.5 21 64 41 52.5 57 34 45.5 28 64 38 51 59 34 46.5 29 67 45 56 60 39 49.5 40 52 31 41.5 49 25 37 41 64 39 51.5 58 33 45.5 52 55 35 45 50 30 40 53 53 32 42.5 47 28 37.5 64 43 28 35.5 39 24 31.5 65 42 24 33 35 20 27.5 76 53 33 43 47 29 38 77 50 29 39.5 42 24 33 87 52 32 42 47 27 37 88 55 34 44.5 50 30 40 Averages 56.6 33.2 44.9 50.5 27.85 39.175 - Mark Barbara Richmond wrote: Hi Jack, I guess the need would be to make more than 1 gram of difference in the touch. ;-) Barbara Richmond, RPT near Peoria, Illinois ----- Original Message ----- From: JWyatt1492 at aol.com To: pianotech at ptg.org Sent: Thursday, January 7, 2010 4:53:50 PM GMT -06:00 US/Canada Central Subject: [pianotech] PUNCHING TRICK ??? Hello to All. For the last 50 or so years the punching "Trick" has been called " Clipping the Centers ". It is not necessary to do any gluing. You clip the center rail felt just a little in front of the center pin hole then replace the punching, clipped side forward. It is generally thought this will make about one gram difference (lighter) give or take. I use my center pin cutter to do this procedure. If you can understand the principal of a see-saw then you understand the principal of a lever. The Herz- Erard action is a group of levers working with each other. Five ( 5 ) to be exact. Not 50 just five. Its really " not " that hard to figure out how to change touch knowing the key depth and the hammer blow distance. You lighten the load, change the fulcrum or reduce friction. Maybe one, two or some of all three. You do not have to make things complicated unless you have " the need ". Jack Wyatt Dallas, -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100108/0e6dc72a/attachment-0001.htm>
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