Much obliged Mr. Erwin! On Tue, Jul 6, 2010 at 8:41 AM, Dale Erwin <erwinspiano at aol.com> wrote: > *My offering of class material to the institute. I'll be doing this in > Feb at West Pac in S.F. > * > > *Dale S. Erwin > www.Erwinspiano.com > 209-577-8397* > > > * >> * >> * Understanding Action Ratios and Hammer weights* >> * * by Dale Erwin, R.P.T. >> * * >> * As piano technicians we cannot confidently guarantee a successful >> action rebuild without understanding that action ratios & key leverages >> are key to our success. Discovering the effects of action ratios reveals >> that an arbitrary installation of hammers is a guessing game! Which... usually >> results in a heavy action, poor regulation,& excessive leading etc. As we >> learn to control these ratios we gain mastery over the action rebuilding >> process. The result produc**es beautiful touch and musical sound.* >> * A simplified definition of an action ratio is how far does the >> hammer rise per unit of key movement. For example... >> 1 mm of key movement produces 5 mm of hammer movement...this equals a 5 >> to 1 ratio and so on. >> Any ratio above 6 to 1 fitted with a too heavy hammer will always >> produce a heavy action and unhappy clients >> * >> >> * Action ratio information allows us to: >> 1. Choose correctly dimensioned parts that correct poor leverages and >> enhance action performance >> 2. determine regulation parameters >> ** 3. Select replacement hammers for a specific hammer weight >> 4. Prepare a specific hammer weight curve for chosen leverages >> 5. Choose a reasonable balance weight removing excessive key leading >> 6. Decide when to move the capstan, and when new keys are in order >> Using the "Erwin action ratio gauge", we will determine an action/key >> ratio in about 5 minutes on typical action and use it to guide the job >> through steps 1 thru 5 using mocked up parts. >> Other related subjects presented: Graphs,tools & visuals will show how >> to prepare a set of hammers for a smooth strike weight curve. Learn what is >> meant by Hammer sampling? and why it is important. >> * >> >> ** >> ** >> >> *** >> >> * >> >> >> >> > > > -- > Ryan Sowers, RPT > Puget Sound Chapter > Olympia, WA > www.pianova.net > -- Ryan Sowers, RPT Puget Sound Chapter Olympia, WA www.pianova.net -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100706/b9a4102a/attachment.htm>
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