<html> <body> Ron - Promise to listen to the link later. For now, can we clarify what we mean by over-centering? (to stay focused, I have already considered and ignored any name-related meanings) Is it the orientation of the shank at hammer/string contact?  orientation of hammer to string at contact?  both? I'm assuming that correct strike point is being achieved.  Also, I seem to recall that the challenge in the Bechstein treble was the thickness and/or proximity of the block to the strike point, where, without the over-strike approach, the hammer would end up rubbing on the block.  Thanks David Skolnik Hastings on Hudson, NY At 02:04 AM 2/23/2012, you wrote: <blockquote type=cite class=cite cite="">Thanks for that Ron, thats interesting. If over-centering is seen as an advantage, what are the limits before encountering negative consequences,and what would these consequences be? Lewis. From: Overs Pianos <sec@overspianos.com.au> To: lewis Newman <musicbased@yahoo.co.uk>; pianotech@ptg.org Sent: Wednesday, 22 February 2012, 22:03 Subject: Re: [pianotech] over centring on bechsteins. Lewis, > I have noticed that all the bechstein actions i have checked always over centre, especially in the treble section?-(Obviously taking hammer wear etc into account). > > I assume they set it up this way on purpose for some reason, but i always thought it was best to have the hammer strike the string at 90 degrees...? Many manufacturers bore their hammers short to achieve an over-centering action. This does have a friction advantage for many, since the contact between the jack and the knuckle is well away from the line of centres for most actions. Short boring the hammers will bring the contact point closer to the line of centres and will slightly reduce action friction - all other factors being similar. Using a smaller knuckle diameter is another way of helping an otherwise ordinary geometry situation. However, one needs to check that there remains sufficient adjustment to achieve an appropriately close drop height, if considering a smaller knuckle. Ron O. -- OVERS PIANOS - SYDNEY   Grand Piano Manufacturers _______________________ Web <a href="http://overspianos.com.au">http://overspianos.com.au</a> <a href="mailto:ron@overspianos.com.au" eudora="autourl"> mailto:ron@overspianos.com.au</a> _______________________ A web page with images of recent work and almost-audio-CD quality mp3 sound files of the Overs piano can be found at; <a href="http://overspianos.com.au/more_info.htm"> http://overspianos.com.au/more_info.htm</a> So put on your headphones, plug them into your freshly restarted computer and sit back to over 20 minutes of pure piano. _______________________ </blockquote></body> </html>