The Stanwood New Action Protocol for Grand Pianos (David Stanwood)

A Simple Approach for Matching Hammer Weight and Action Ratio in the Grand Piano to Control Inertial Playing Quality – By David Stanwood

Our piano industry holds the belief that a high, medium, or low Down Weight is associated with a heavy, medium, or light action. Experience teaches that the association is unreliable. A well voiced and regulated piano with a medium Down Weight can sometimes feel heavy or light. The underlying and overriding factor is the “Inertia” of the leveraged hammer weights. The normal range of Leverage Ratio and Hammer Weight levels in grand pianos varies widely and finding the correct match is key to producing a desired playing quality. When Ratio and Hammer Weight levels are paired for specified Inertial types, the amount of weight needed to balance the keys to a specified Down and Up Weight is always similar. This leads to a simple, practical, and calculation free approach. A handful of “Marker” keysticks are tipped onto a digital scale and the weights set on top to mock up a normalized Front Weight associated with the desired inertia according to reference tables. The mocked up keysticks are installed and the weight of each hammer on the marker notes is adjusted to produce the specified Touch Weight. Once the correct Hammer Weight scale is established and the action balanced with key weights, the desired quality of Inertia will result.

David Stanwood

David Stanwood discovered the Equation of Balance and pioneered the field of Touch Weight Metrology. He is the inventor of his trademark product – Precision Touch Design.  For 3 decades he has practiced and taught his methods for scaling Hammer Strike Weights and Key Front Weights.  His work produces the intended Inertial Playing Quality with the smoothest possible touch response from key to key.  David was inducted into the Piano Technicians Guild Hall of Fame 2019. The Precision Touch Design Academy Europe was founded on his method in 2008.  He received the Distinguished Alumni Award from the North Bennet Street School, Boston, Massachusetts, USA 2007.  He lives and works on the Island of Martha’s Vineyard off the North East coast of the United States.

Petrof Pianos

PETROF upright and grand pianos are traditional products from the Czech Republic. Since its founding in 1864, the company has built more than 635.000 instruments. PETROF is a family-run firm that trades in 5 continents and exports to more than 65 countries the world over. Their pianos are popular among musicians for their unusually soft, gentle, rounded, and romantic tone. The portfolio of grand and upright pianos known under the PETROF name is very wide and sufficient for the requirements of a diverse group of customers. It is, however, quite usual for PETROF to build instruments exactly in line with customers’ wishes.

In 1954 PETROF founded its Department of Research and Development where they further perfect their instruments and measure and fine-tune every part of the piano that affects its acoustic properties.



Steingraeber & Söhne

Steingraeber & Söhne has been making uprights and grand pianos in the Wagner Festival city of Bayreuth since 1852. At present, the family owned business has thirty-five employees who produce top quality, handcrafted instruments on a daily basis. Advancements in the construction of world-class instruments are the result of the continuous desire to innovate. Internationally recognized artists play Steingraeber pianos, which are regularly crowned with prizes throughout the world. Udo Steingraeber represents the sixth generation of Steingraeber piano builders. He has led the company since 1980.



Knud Danielsen ApS

Knud Danielsen ApS is a global supplier of piano spare parts for the industry.

The company was established in Denmark in 1935 and offers a wide range of quality products to manufacturers, dealer`s and technicians.

The company basic principles are reliability, honesty, responsibility and daily work by management and employees is performed with a high level of service, accuracy, and positive work ethic.

With three generations of experience, the company is continuously expanding their assortment of quality products at competitive prices, which today place the company among Europe’s leading suppliers of piano and grand piano parts. Knud Danielsen ApS remains a 100% family-owned business for which tradition, service and quality are paramount. You can find more information about the company’s activities and product range at its website www.knuddanielsen.dk


Hellerbass began producing piano bass strings in 1985. Today, Hellerbass with its seven employees supplies repair shops and branches of the piano manufacturing industry with bass strings for upright and grand pianos. Among our established clientele are leading piano restoration workshops and some of the biggest piano retailers in Europe and overseas.




Gazelle is an all-in-one software for piano technicians. We help you save time, wow your customers, and grow your piano service business. Established in 2014 and currently serves piano technicians in over 36 countries. Gazelle was founded by Timothy Barnes, a Registered Piano Technician and Luke & Nathan Ehresman; veteran software developers with decades of experience developing sustainable software for large and small organizations. Your success is our mission, and it’s what keeps us working hard to keep making Gazelle the best business management software it can be for the piano service industry.



We are an industry portal and sales channel that has been in existence since February 2014, dedicated to connecting sellers and buyers of pianos or grand pianos. We are engaged in promoting online more than 1200 piano showrooms from all over the world providing them with coverage within their country or worldwide. We seek solutions through online services to enable piano salons, piano technicians and piano tuners, piano manufacturers and piano transport companies to grow their business. We also offer services to promote piano listings for sale to private advertisers. We are pleased to support Piano Congress as a media partner for the event in September 2022.




Piano Life Saver

Piano Life Saver is made by the employees at Dampp-Chaser Corporation, a third generation family-owned business that manufactures and supports products which provide humidity control for things that matter to you. From our headquarters and manufacturing facility in Hendersonville NC, Dampp-Chaser technology solves problems ranging from mildew in your closets to protecting priceless grand pianos in famous music venues worldwide. Direct frequent contact with consumers and technical professionals have earned us a reputation for unparalleled product quality and exceptional customer service.


Piano Renovation Professional

Piano Renovation Professional S.C. has specialized in the music industry since 1986. The company renovates pianos and grand pianos, sells tools, parts and accessories for pianos and grand pianos. It holds licenses for the installation of “silent playing” systems and PianoDisc self-playing systems. Piano Renovation Professional S.C. is the sole agent of Jahn Pianotaile company in Poland, famous all over the world for high quality of supplied materials for the repair of keyboard instruments.



WR-Piano was founded in 1995 by Wojciech Rosinski, who gained experience in the Calisia piano factory. Currently, the company employs 20 specialists who are perfect in their craft.

Every month, about 15 instruments that look like new leave our workshop. New investments will allow us to increase the number of repaired instruments.


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