Posts tagged shaping
Recently i’ve had the opportunity to work on a church piano – an older Chickering. But i must say, this piano was an interesting one to tame. I use the word tame because it was out of control. The touch was not only uneven but INCREDIBLY difficult to play. Most fine pianos have a touch weight of about 50-55ish grams of weight at the key. This one was a whopping 80+ !!! First things first… chase down the friction. That blog will be for another day though. After friction was in the ballpark, i was still faced with a piano that had a touch of 65ish grams. Time to consider putting this piano on a diet. Yep. You heard me. This piano was overweight and i was about to transform the touch.
So where does weight come from? Many months ago i wrote a blog on piano weights. It can simply (and yet so difficult at the same time) be measured in 2 forms – static weight where we are doing a dead lift – the hammer has yet to move. The other is created by rotational inertia. The hammer has started to move… how much effort is required to continue to move the mass of the hammer. The former mainly deals with soft playing… we’re not concerned about velocity but simply getting the hammer in motion. The latter however deals with everything above soft playing and truly is the more important factor. Static weight can be counterbalanced in the key like a see-saw. Rotational inertia however can really only be changed through the mass of the hammer itself. Because static weight again really only affects soft playing, when i sat and just played the piano (after friction was removed), it still felt heavy and burdensome. So it was time to trim the fat – reduce what i could on the hammer without compromising either structural integrity or tone. How does one leave the strike point of a hammer the same and yet reduce dead weight? Take a look at the pics. The one on the left is the original. Square and bulky. The one on the right – the more parabolic shaped one is one i adjusted. The tapered ‘shoulders’ of the hammer offer insignificant contribution to tone… if any. And so i spent the next 3 hours shaping hammers. Take a look at the two ‘tails’ – the end parts of the hammer. On the left – one that is tapered while the right, original. The net result? Reduction in about 1.3-1.5 grams of fat. One point three??? Perspective here… a nickel weighs 5 grams. You ask “How does anyone get excited about 1.3 grams of weight?” Ahhh therein lies the magic. Every piano has an ‘action ratio’ meaning one gram at the hammer accounts for usually around 5 grams at the keyboard. OK so do the math… this piano has a 5.5 action ration. 1.3 gram reduction x 5.5 action = 7.1 gram reduction of touch weight – the exact amount i needed to make this piano feel dynamic and alive. I’m so happy! 😀