My first thought was as Paul said, a bead of glue that leaked down from the hammer shank, but if it's happening on all of them, that idea is eliminated. One test you can do is lift the hammer a little so the jack will clear the butt and then reach in and trigger the jack, if you don't hear the sound when the jack snaps back into position then it's not the butt felt.
On Baldwins, post corfam, they used a tawny colored material that got hard and the jack slams against the butt "leather" before sliding down underneath the butt. That creates the same slapping sound that you describe, I ran into that recently on a non Baldwin but I can't remember what it was, on that one the butt and catcher leathers were a very dark color, almost black. If it's hardened synthetic butt leathers I don't think there's a solution save replacing them.
Wurlitzer was owned by Baldwin in the 90's so maybe they were using the same action parts or old Baldwin stock. Another sign that it's that material that gets hard and slick is if the checking is really bad, 1 inch plus. Actually, if that's the case, you can restore the checking to 5/8" and it will reduce the jack travel/momentum and it might at least quiet them down a little.
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Steven Rosenthal RPT
Honolulu HI
(808) 521-7129
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Original Message:
Sent: 11-17-2022 23:23
From: Paul McCloud
Subject: Wurlitzer Console- Jack slam
You might check for excess glue squeeze out or saturation of the felt. Baldwin was prone to that in many cases with bushings and other felts. That would account for the slap sound if the jack was hitting excess hard glue.
If the jack is hanging up on the butt leather before it goes back to the butt felt, it could also make a slapping sound when the jack tip frees up and slams onto the felt.
All the above comes from my mind's eye. FWIW.
Oh, yeah, strong jack springs could make it more likely to make that sound. I like my jack flanges pretty loose, but it's not critical as long as they work. But I'll bet it's not the spring(s).
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Paul McCloud, RPT
Accutone Piano Service
www.AccutonePianoService.com
pavadasa@gmail.com
Original Message:
Sent: 11-17-2022 22:01
From: James Kelly
Subject: Wurlitzer Console- Jack slam
I am trying to figure out the cause of a noise created by the jack when it returns under the hammer butt after play. The sound is quite annoying and I tried a number of things none of which eliminated it . I needled the felt pad that the jack hits but nothing improved . I needled the butt leather, adjusted the capstan to give the jack more clearance but it seems to momentarily hang up in the butt an then snap into the felt pad. The jack springs seems a bit strong . Does the jack without the spring have a gram measurement- in other words should it be 1-2 grams on a gram gauge. Perhaps I should remove some of the felt jack stop pads and replace them. Or maybe the hammer rail cloth and the felt that the back of the keys sit on . Once I solve it once I only have to do it 87 more times. The piano was bought new and built in 1992 if that helps.
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James Kelly
Owner- Fur Elise Piano Service
Pawleys Island SC
(843) 325-4357
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