<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html>   Phillip Ford wrote: <blockquote TYPE=CITE>>Ideally, I would like to see them do exactly the same amount of work for >each key. But that means a very well and evenly balance action to begin >with... which you are only going to get with Stanwood like proceedures. This was my original thinking.  However, I noticed that the Renner turbo wippens don't have springs on the top wippens (although they offer a kit so that you can fit them yourself).  So their thinking apparently is to utilize more assist in the bass than the treble.</blockquote> Thats largely because at that point hammers are so light that any spring force upwards will tend to lift the whippen off the capstan. Actually thats one of the neat things about my magnet solution presented in the virtual capstan thread a while back, they dont have that problem.... but thats another story. Some actions have even very strong whippen assist springs all the way up to note 88.... but then they used heavier hammers up their to avoid the floating whippen problem. The whole point goes to illustrate one of the problems with whippen assist springs in general. Not that I am saying assist springs are a bad thing mind you.. I'm just saying I think some of the consequences of their use have been overlooked, and others have not been fully understood. <blockquote TYPE=CITE>  >I agree with your second, and think any leverage assist mechanism should >be limited to doing the job of maximum  5 grams of FW This was also my original thinking.  This equates roughly to a 10 gram reduction in WW.  The wippens with springs engaged don't lend themselves to WW measurements using the typical Stanwood kit.  I made a simple jig on which to mount the whippens so that I could measure WW with the springs engaged.  My plan was to adjust the spring to reduce WW from roughly 18 g to roughly 8 g.  I also checked the angles of the wippen in the action at rest and at full keystroke and checked WW with the wippen at these angles on the scale using my jig.  The problem is that if you set WW at roughly 8 g (in other words a 10 g spring assist) at the rest position, at full stroke the spring is providing no assistance at all.  So, during the keystroke you transition from a 10 g assist to no assist at some point.  This didn't seem like a good thing to me.  So, I was going to opt for setting and checking the springs to give some assist with the wippen at the full keystroke angle and taking what I got at the rest angle.  This results in a negative WW in the rest position (in other words spring assist is more than the WW with no spring - or in more other words the wippen would be floating in the air above the capstan (with no hammer weight on it of course).</blockquote> And this goes to point out another of the problems that needs to be better thunk through :)... negative whippen weight ... is that or isnt it a good thing... And just how much of it do you need to get any help at all with forcefull play... and what about the transition to higher notes where high levels of negative whippen weight will cause floating whippens.... what does that graduated change that you'd have to employ really result in....  the bass keys will have a real steep touchweight gradient and the higher keys will act as if they had only counterbalance weights....  In other words... the bass hammers will be much heavier with forcefull play then the treble hammers... and at soft play they will feel the same... Is this what you really want ?? perhaps so... perhaps not.. I'm just saying we need to be aware of what we are really doing with these... Stephens article touches a bit on this... and its worth thinking through a few times.. My own reaction so far is to solve the problem by not using assists, or if I do use them for only minimal amounts... so I dont have to deal with the kinds of problems above. But I am fascinated with the idea of graduating the touchweight gradient. It may be a good thing if implemented purposefully enough. <blockquote TYPE=CITE>  >I measure in terms of FW. > >Cheers >RicB How are you doing the actual measuring.  Are you measuring the wippen (such as I'm doing with my WW measurements) or are you measuring at the key.  To me FW only has meaning for the key itself.  Once it's installed on the keyframe and the wippen is put on it you're measuring DW or UW.  Are you measuring differences in DW or UW for changes in spring strength? Phil F <a href="https://www.moypiano.com/resources/#archives"></a> </blockquote> I actually dont get into directly measuring spring tension... what I do is insure the best possible action balance with the springs dissengaged, and then engage them to even out the resulting balance weight. I strive to keep this to within around 2 grams of front weight... so any leverage assist mechanisms are not called upon to do much work. << Measuring >> then is just indirectly implied by whatever BW variances I've evened out... if you get my meaning. If you do set up an action like you mention above... please keep track of how pianists react, and share with us your experiences. My magnet leverage assist piano is presently in an off the wall configuration... and hearing some of the comments I get is really interesting.. and instructive. Cheers RicB   -- Richard Brekne RPT, N.P.T.F. UiB, Bergen, Norway <A HREF="mailto:rbrekne@broadpark.no">mailto:rbrekne@broadpark.no</A> <A HREF="http://home.broadpark.no/~rbrekne/ricmain.html">http://home.broadpark.no/~rbrekne/ricmain.html</A> <A HREF="http://www.hf.uib.no/grieg/personer/cv_RB.html">http://www.hf.uib.no/grieg/personer/cv_RB.html</A>  </html>