Hi list - I tuned a 1907 Mason & Hamlin upright recently, and I noticed interesting components on the jacks and catchers that I hadn't seen before (see attached photo). There is a brass piece on the backside of each jack which looks like it might serve as a spring to help the jack return under the butt. The pic is pretty fuzzy (taken with my cell phone), but I think you can see that the brass piece is flush against the backside of the jack, and it's flat except for a small "crook" near the top. This shape is what makes me think it's a spring. There is also an extra piece on the backside of the catcher which aligns with the crook in the brass piece, although (at least in its current poorly regulated state) the jack doesn't go back far enough for the brass piece to actually contact the back of the catcher. The piece on the backside of the catcher has a thick, dense felt similar to backcheck felt. The jacks also have the standard coil spring under the tender. I know M&H was pretty inventive and often experimental with many components of their pianos in the early 20th Century, so I'm not surprised to see something new, but I'm curious. Has anyone seen these before? Am I right in guessing that these are an assist spring for speedy jack return? If so, when I regulate this piano, should the blow distance be set such that, with proper dip and aftertouch these brass pieces DO contact the backside of the catcher? Scott ------ Scott A. Helms, Registered Piano Technician 480-818-3871 www.helmsmusic.net -------------- next part -------------- A non-text attachment was scrubbed... Name: jack spring.jpg Type: image/jpeg Size: 12068 bytes Desc: not available URL: <http://ptg.org/pipermail/pianotech.php/attachments/20091007/9db0f5b1/attachment-0001.jpg>
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