Hi Dale, If that could be incorporated easily into this, the same type of info might also be interesting to someone who isn't or can't replace the hammers. Just trying to improve what's already there. Just a thought. Avery Houston On Tue, Jul 6, 2010 at 10:41 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 > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100706/80663041/attachment.htm>
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