Weighting upright keys question

[Fenton Murray]

I've back leaded a few spinets, it really fixes them. Afterall the keys are easy to pull, it's the actions I don't want anything to do with. Kind of like was stated in an earlier post, I just draw a line after trying a few sample and take them home to the drill press. I don't think it takes much longer than a tuning or two to do this.
Fenton
  ----- Original Message ----- 
  From: Farrell 
  To: Pianotech List 
  Sent: Sunday, February 17, 2008 7:25 AM
  Subject: Re: Weighting upright keys question


  I also have an interest in learning how to improve upright action touchweight.

  I have done much the same as you write Fenton, but I have on some instruments gone so far as to do a Stanwood-type Strike Weight evening/tapering and even/taper out key Front Weights the Stanwood-type way, i.e. where one eliminates friction from the process. I use a number of sample notes, get the friction as close to target as possible, then evaluate what kind of leading is optimal (DW/UW). Then I take the keys out and put them on the Stanwood-type touchweight stand and weight off FWs to get an even taping on them. 

  After all that, one still may have some inconsistencies in touchweight, which I even out with minor hammer butt spring tension adjustments. I figure this process gets you something like the Stanwood-type optimized grand action - the hammers and keys are all nicely weight evened/tapered, and any touchweight anomalies can be easily rectified by getting friction back into the optimal zone and/or regulating butt spring tension.

  Not sure this the most optimal way to go, but it seems like the closest approach I could find to evening out touchweight on an action, and retain the ability to correct it in the future very easily through friction (first/preferably) and butt spring regulation.

  I haven't done this process on any Gulbranson spinets.   ;-)

  Terry Farrell
    ----- Original Message ----- 

    >In general, is installing weights in upright keys a corrective remedy?
    Depends on the situation. (Always a good answer.)
    >If so, is to correct due to wear problems or to improve upon original factory specs? 
    Probably not wear, that would be a fine adjust. Factory spec? Well, yea. Or to change it to you or the customers liking, as in custom(er) work. 
    >What do weights in an upright correct?
    OK, what we want is a specific balance weight (bw). at least I do. Given a certain friction in the piano we are going to want to set up something like maybe a downweight (dw) of 50 and an upwight (uw) of 25. All numbers in grams. This is assuming a friction of 12.5.
    DW-UW(2)=Friction. This is done my adding or subtracting weights in the key to achieve the numbers you want. This is heady stuff, Julia, if you haven't gotten into it before. But, it's easy if you just sit at the keyboard with some gram wts and move around lead key wts on the top of the key to get certain results. 
    But back to what do the weight in an upright correct. Uprights usually need wt at the back of the key. Some of them had no wts installed. An easy upgrade is to add wt to the back of the key to achieve, let's say, 25 grams of upweight at each key. A lot of spinet and console pianos will really benefit from this. This work was not done at the factory.
    Hope this helps.
    Fenton
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