Bosendorfer grand action, rebuilt in Poland, was coming to our workshop to modify touch weight and get servicing.
This action showed typical polish rebuilding quality as usual i.e. poor details even cosmetically good. It has new hammers & shanks. Major worn parts were replaced. But there were many details where not good enough for the level which the client wanted to play such as too heavy touch weight, poor regulation, limited tonal possibilities. The client wanted to have standard touch weight because of too heavy at the moment. Also expected good variety of tonal palette as well as comfortable play-ability.
今年一台目の仕事はタッチウエイトマネジメントでした。大ボスが持ち込んできたこのピアノ、ポーランドで大修理されたものだそうです。ポーランド修理のピアノは他にも見たことがありますが、ほとんどが「外装はきれいだが内装は？」の品質が定番ですが、このピアノも果たしてその通りでした。ハンマーやシャンクは新品、各部のフェルト・クロス類も交換されています。
顧客はアマチュアのピアニスト、買ったは良いがタッチが重すぎて弾けないからなんとかしてほしいとの要望。
Initial observation showed below results;
- Hammers were not tapered nor tailed
- Knuckles were lubricated (?) with too much graphite (photo below)
- Key balancing was done. it seemed OK cosmetically.
- Key bushings were all tight, balance holes are loose
- Shank & whippen flanges seemed tight
- Strike ratio by 2g weight was 5.8.
初期観察の結果、
①ハンマーのテーパーやテール加工がされていない、
②ローラーがジャックが触れないところも含めてべったりと黒くなっている（下写真参照）、
③鍵盤鉛はそこそこ悪くなさそう。やった形跡はあり、
④鍵盤ブッシングがガタなし。バランスホールはスカスカ。
⑤シャンクフレンジとウイペンフレンジは固めなのでトルク調整要
⑤２ｇおもりによるSRは5.8、と意外に悪くない。
Too much graphite was applied
The elements of Equation of Balance by Stanwood protocol were like below:
- BW: 37g to 40g, Standard
- SW: #8 (3/4 medium) ~ #9 (Top medium)
- FW: relatively lighter side in bass and tenor, similar to ceiling level
- KR: 0.44 ~ 0.47 within 6 sample notes, smaller ratio and uneven
- SR: 5.4 ~ 5.6, relatively smaller than normal action
- F: 12 g ~ 17 g, normal to a bit bigger
These figures show actually it is within reasonable standard, but it is felt if one played it. I supposed friction was the main cause especially key bushings.
サンプル鍵盤でのスタンウッド測定の結果は、
BW：37g～40g で標準
HSW：＃８～＃９
FW：低中は比較的軽め、次高はシーリング値付近
KR：0.44~0.47と普通より小さめでばらつき大きい
SR：5.4～5.6と普通より小さめ
F：12g～17g
これらの数値から見るとスタンウッドの標準値から見ると意外なほど悪くないわけですが、実際の弾いた感じはかなり重いのです。フリクションの影響がかなり大きいのではないかと思われました（特に鍵盤ブッシング）。
See first half of the SW in the smart chart below which they are plotted in blue for even numbers. The green line shows target level. Red dot at mid-C is adjusted as sample. It was not felt so heavy in top treble section, so the hammers there were not required much reduction.
偶数鍵のスマートチャートは次の通り。サンプルで試した４０Cはテーパー削り済で赤印。他はオリジナルの値。緑線が目標HSWライン。高音部は現状で重すぎないため、無理して削らないカーブにしました。低音の上の方と中音部が特に重めなのがわかります。
SW (even numbers) plotted on Smart chart in blue
As SR was low even from standard already, it can't be decreased because the action may need too deep key depth to get after touch due to lower action ratio. So in this case, reducing hammer weight and treating Friction would be the area needed to be done first. The FW values could be adjusted by calculation of Stanwood's equation of balance before assembling. then see how SR can be adjusted later.
方向性としてはHSWを中低音を中心になるべく軽く揃えて、フレンジ・鍵盤ブッシング・ローラーなどのフリクション部分をしっかり調整し、鍵盤鉛はFW基準で事前に調整、そして整調まで仕上げた段階でSR調整をするかどうか決めることにしました。
Re-centering shank flanges, blush knuckles, adjusting SW, pre-voicing and tailing while hammers are out
Weight before and after tapering
HSW調整では削る前の重さを量り、削った後に必要量減ったかどうか比較します。HSW測定のやり方をする必要はありません。
Smart chart, completed SW (red)
Completed SW adjustment shows smart chart above. Maximum 1.1 g of reduction. No hammer lead was needed.
奇数鍵も含めて仕上がった段階のスマートチャート。赤点が仕上がり。最大1.1gの減量をしました。ハンマー鉛入れの必要はありませんでした。
FW graph, Blue: original, Green: target and red: FW ceiling by Stanwood
Key balancing was done with traditional way in Poland I supposed. FW graph shows really uneven weighting result. Due to variety of friction level, uneven SW (blue in smart chart above) and FW, the action should be felt very unevenly.
With this work, SW and FW were adjusted smoothly and F was corrected to standard. Final touch weight will be much better. More variety if we find still will be caused by uneven SR which is expected by uneven KR.
FWのグラフ。赤線がシーリング、ぎざぎざの青線がオリジナル、滑らかな緑線が目標FW値（仕上げは±1gで調整しました）。
After regulation, the action was played and measured to check touch weight. It was felt slightly still heavy on white keys in tenor and bass. Those areas showed actually higher KR (and SR) at initial measurement. So we decided reducing SR by cutting balance punching cloths in the area (only white keys). Cut 1/3 in tenor and 1/2 in bass by reflection of KR figure.
整調をある程度やったところで試弾。大ボスと打ち合わせの上、中音から低音の白鍵をもう少し軽くしたい、ということでパンチングクロスをカットしました。KRが中音白0.45黒0.44、低音は白0.46黒0.44だったので、低音白は半カット、中音白は三分の一カットにしました。
Gluing half cut punching cloths in bass
1/3 cut cloth doesn't need gluing to key stick or paper washer
中音白鍵はクロスの穴を残す形でカットしたので、そのまま貼らずに入れてあります。低音は半カットして既存のパンチングペーパーに貼ることにしました。
整調を軽く見直しておしまいです。
The work completed followed by touch up regulation. The action was returned and set up to the piano.
3 days Touchweight Management seminar lead by myself will be held in Sydney, Australia in April 2018. Please contact me at yuji3804@gmail.com if you are interested in participating it.
