The plate is not cracked. Floyd This is where you might be wrong. From what you telling us, this sounds like a cracked plate problem to me. I would suggest you take out the action and check the plate struts in the middle. But be very careful. The first sign that the plate is be cracked is if you have a very hard time removing the action. Wim -----Original Message----- From: Floyd Gadd <fg at floydgadd.com> To: pianotech <pianotech at ptg.org> Sent: Sat, Jun 12, 2010 5:40 pm Subject: [pianotech] Tuning Fail A couple of months ago I worked on a New Scale Williams (Canada) piano. It's a large vertical, from the teen or twenties of the last century. I tried to tune it but found myself chasing the pitch. It was late in the day, lighting was poor and getting worse, and it was one of the pianos that has the pressure bar cast into the plate, hindering access to and visibility of the treble section. By the time I left it was better in tune than when I started, but I did not consider the work to be at a billable standard, so I simply arranged to return. I returned to the piano today, starting late morning, and bringing my own light source. I anticipated that I might be chasing the pitch for a while, but I was going to chase it until it landed. It never landed. The piano was largely sharp, maybe 5 to 8 cents, some places a little more. I did an initial pitch correction pass, using Tunelab Pocket with my usual pitch correction settings. I did a second pass with no overshoot. I then used my split mute to survey the state of the center strings of the middle section. Lots of sharp notes. I did another pass of the middle section, and was finding notes up to 8 cents sharp. I would tune several notes, go back and check my work, and find that it was sharp again. After maybe three or four passes, most of the notes were stabilizing, but there were rendering issues that was making everything move along very slowly, the kicker, about 3 hours in (!) was the last note before the strut at the top of the middle section. 5 cents sharp. Tune the middle string, bring in the unisons, now it's five cents flat. Back and forth and back and forth. I checked the lower half of the treble section. Nothing at pitch, everything sharp. Feeling awkward already, having been at it so long, I billed the customer for the repair I had completed (a missing treble string), and admitted that the piano had won the the round. I've been tuning pianos for 7 years. I'm not unaccustomed to rendering problems. But this is the only time I've been defeated by a piano like this. Tuning pin tightness is good, except for a couple. The bridge is not loose. The plate is not cracked. The upper termination point for the tenor and treble strings is not a cast surface, but a long cylindrical rod in a groove on the plate. The unisons agree with each other, but whole ranges of notes simply will not stay where I put them, even after multiple passes. I was unable to diagnose the problem. What am I missing? Floyd Gadd Manitoba Chapter -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100613/abadb8e8/attachment-0001.htm>
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