To get the composite reading, don't you simply add the front and rear angles and divide by two to average and get the proper value for the bearing angles? ugh...no...now I see why you were trying to find some reliable reference to work off of...this will just complicate your life immeasurably, help you to make mistakes, and give a reading that has no practical value, ie doesn't mean anything. The way I described using it uses the device as an indicator to determine composite angle by simply noting the difference between front and back angles. Uh, I don't need any help making mistakes or making my life complicated, I do that well enough on my own, thank you. As a side note on downbearing, as an experimenting belly designer myself (getting better too, I must say, yay), you might find it useful to intellectually chuck everything you knew, or thought you knew about downbearing and start fresh in your thinking, especially in an rc&s design (if that's where you are going). Reading through trad approached to determining and setting downbearing will just take you down confusing dead ends, as rc&s vs cc behavior is not apples to apples in this regard. The composite angle gives you (individual string lbs bearing= sine of composite angle x individual string tension) a way to determine how much load the board has to carry...thats all thats of practical use...at least thats the way I'm using this measurement. Well, my mind has been getting expanded, sometimes fighting tooth and nail. I'm just trying to sort out the blooming, buzzing confusion into coherent thought forms.. I'm not doing R, C, & S yet, but a hybrid rib crowned board based on calculations that Jude Reveley has been helping me with to establish rib crown, bearing load, deflection, etc. This early in the game, just managing the new skills of installing boards is a lot to know. Add this stuff, and my little ole brain gets chock full and starts to overheat. For example, I really don't know what practical value the measurements you are taking on the old B have, other than to maybe help you decide the elevation of the plate or something. Seems like it would be useful to see in a very general sense where the board failed, but past that, it would get you thinking apples to oranges and just confuse your new design thought right from the beginning...no? Strictly speaking, no practical value since I am yanking the board and chucking it into the trash bin. I was just playing with the gauge to see what kind of readings an old dead board would give me, and to practice using the little bugger. I checked my readings today with my new found knowledge, and they are different - more in line with what I would expect this old board to be: Note 2: Rear angle differential is + 1.1. 19 is .2, 41 is -.1, 50 is 0, and 54 is -.2. Some further clarification needed: From your list yesterday. speaking length (up arrow), backscale (up arrow, higher reading that speaking) the bearing is positive I'm still a little confused. If I zeroed on the speaking length, why would the arrow be up or down if it is at zero? Please explain what I am still missing here. I understand the rear angle thing, but not this. Thanks again. Will From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of jimialeggio Sent: Thursday, August 12, 2010 8:33 AM To: pianotech at ptg.org Subject: Re: [pianotech] Whistlin' Wixey On 8/12/2010 6:08 AM, William Truitt wrote: Hi Jim: Thanks for the thoroughness of your reply. Well, ain't I the numby dummy! I didn't take note of the arrows, and assumed that if the reading was negative, there would be a minus sign in front of the number value. (That assuming can sure get me in a lot of trouble). In my own feeble defense, there is nothing in the directions indicate what the arrows mean, at least not the ones I got. So chuck my readings out the window for now. I was wondering why I had no negative readings, particularly on that old B board the arrows tricked me the first time I used it too. Regarding the composite angle you describe, I assume from what you write that the only thing you are measuring is the difference, positive or negative, between the front and rear bearing. Yes? yes I have long read that the bearing angle should be between about .5 degree and 1.5 degrees, depending on where you are in the piano. I don't want to assume anything again, so I will ask the question - does the value you record using this method correspond directly to the values just given (and which I believe are a component reading)? yes To get the composite reading, don't you simply add the front and rear angles and divide by two to average and get the proper value for the bearing angles? ugh...no...now I see why you were trying to find some reliable reference to work off of...this will just complicate your life immeasurably, help you to make mistakes, and give a reading that has no practical value, ie doesn't mean anything. The way I described using it uses the device as an indicator to determine composite angle by simply noting the difference between front and back angles. The up and down arrows as described in your list (thanks) have meaning only in relation to the zero point, and are not in and of themselves an indicator of positive and negative bearing. thats right As a side note on downbearing, as an experimenting belly designer myself (getting better too, I must say, yay), you might find it useful to intellectually chuck everything you knew, or thought you knew about downbearing and start fresh in your thinking, especially in an rc&s design (if that's where you are going). Reading through trad approached to determining and setting downbearing will just take you down confusing dead ends, as rc&s vs cc behavior is not apples to apples in this regard. The composite angle gives you (individual string lbs bearing= sine of composite angle x individual string tension) a way to determine how much load the board has to carry...thats all thats of practical use...at least thats the way I'm using this measurement. For example, I really don't know what practical value the measurements you are taking on the old B have, other than to maybe help you decide the elevation of the plate or something. Seems like it would be useful to see in a very general sense where the board failed, but past that, it would get you thinking apples to oranges and just confuse your new design thought right from the beginning...no? Jim I -- Jim Ialeggio grandpianosolutions.com 978- 425-9026 Shirley, MA -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100812/bbe8aa0e/attachment.htm>
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