I think you're right that it helps return the jack...I've got an old Mason/Hamlin with the same thing and that's what I thought it was...I mean what else? David Ilvedson, RPT Pacifica, CA 94044 ----- Original message ---------------------------------------- From: "Scott Helms, RPT" <tuner at helmsmusic.net> To: pianotech at ptg.org Received: 10/7/2009 6:00:08 PM Subject: [pianotech] Interesting upright jack >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
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