Hi Tom, The nose bolt has two functions, 1. It prevents the plate from bowing upwards by reducing the span. 2. The secondary effect is to improve tuning stability by making the plate more rigid. Depending where the bolts are located, the length of span and amount of plate flex can be significantly reduced. If I were designing a plate and had to install bolts to prevent plate ringing, I think I'd go back to the drawing board and strategically add mass. Because each time you drill a hole in the board, to allow for a bolt, you create an area for cracks to start. The stripped nose bolt could have been stripped because the plate elevation was incorrect from the start, then some one cheated by tightening the bolts to obtain bearing. Humidity, stress, and the type of lumber used in the support post, conspired to cause the threads to strip. Plate nose bolts are meant to just come into contact with the bottom of the plate and then be tightened. In the case of plate screws, (no support under the plate) these should only be tightened with caution after the piano is strung, to prevent stripping. Regards Roger >Which raises some questions: Are nose bolts absolutely necessary to >maintain the integrity of the plate or are they just there to dampen the >ringing? Does it depend on the piano? How does a nose bolt get >stripped????? > >Tom >-- >Thomas A. Cole, RPT >Santa Cruz, CA >mailto:tcole@cruzio.com > Roger Jolly Saskatoon, Canada. 306-665-0213 Fax 652-0505
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