We have a Bechstein M (6') that dates from the mid seventies. I have also experienced pretty severe tuning instability, unison shift like you have. Also, I observed the same "steep-ish" approach angle as well. Tuning Pin torque is less than what I would like but is adequate. Besides unison drift, a tuned unison still has a very "fuzzy", muddy sound. I found that bridge pins can be easily pulled out with round nose pliers. The piano is now in the shop for new strings, pins (tuning and bridge), other bridge work, and hammers. I was surprised to find that the original tuning pins (#1's) are notably smaller that the #1 pins available from Piano-Tek and others. Somewhat shorter, too. The "threads" on the originals are not what I'm used to seeing, not rolled or cut, but rather look like the pins have been scored between two files! Very un-uniform. There are spots on the pins where there is little to no "threads" at all. Has anyone else seen this? I'm keeping the pinblock because of budget and time constraints. I think I might get by with using the larger new #1 pins, if not I'll go with #2's. A little longer, as well. This is probably not a answer to your post, just commiseration. Maybe some others will chime in. -----Original Message----- From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Geoffrey Pollard Sent: Thursday, October 15, 2009 8:15 PM To: CAUT Subject: [CAUT] Bechstein model B tuning stability I'm interested to hear from anyone who has any 3 -5 year old Bechstein model Bs in heavy use, and would care to share your experience of tuning stability in this piano. I'm having severe unison drift in the lower capo section (10 - 15 strings/up to 5 cents/individual strings within the trichord) within 10 days of tuning; remainder of the piano is rock solid. We have 10 Bechsteins and the ones giving trouble are in keyboard teaching rooms and get heavy student use outside teaching hours. Other pianos in these rooms ( S&S B and Yam C5) are stable. I have diagnosed rendering problems due to a steep-ish approach angle to the capo. I'm now 2 months into a regime of revisiting fortnightly to rectify just the unisons, with a major focus on hammer technique. They are still not stable. Also happy to talk off list, thanks, Geoffrey Pollard GEOFFREY POLLARD | Piano Technician SYDNEY CONSERVATORIUM OF MUSIC C41, MACQUARIE STREET, SYDNEY. 2000 T 61 2 9351 1221 | F 61 2 9351 1287
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