Harpsichord

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Neupert progress: brass slides

  • 1.  Neupert progress: brass slides

    Registered Piano Technician
    Posted 03-01-2020 14:19
    Hi,

    Got started on it this morning. The rails came out easily, through the bottom of the slot, once I disconnected the knee lever and pulled the two support blocks. The rails looked pretty grimy, and the contact surface of the belly rail and the back edge of the wrestplnk felt pretty rough. So I used progressively fine sanpaper to smooth them a bit. In the process I discovered a shim in the bass end of the gap, whose purpose, apparently, is to take up the extra millimeter of width on that end that I discovered during the initial examination. So it appears that the one-millimeter discrepancy in gap width between the treble and bass ends does not indicate narrowing of the gap due to cheek twist or anything else like that. I hope... In the process of sanding I also came upon two small protrusions from the belly rail into the gap which I sanded smooth. Those might have contributed to the rails getting stuck in place. Still trying to figure out what - if anything - to do about gap spacers. there's so little room for them... It also looks like the bushing cloth covering the slide support blocks could use a little cleaning and dusting with teflon powder - or, perhaps, replacement...






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    Israel Stein RPT
    P.O. Box 68141
    Jerusalem, Israel 9168002
    510-558-0777
    istein248@gmail.com
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  • 2.  RE: Neupert progress: brass slides

    Registered Piano Technician
    Posted 03-01-2020 15:41
    Those round jacks take up a good bit more space than the standard rectangular ones. It is quite likely that gap spacers are out of the question. But it looks like the accumulation of gunk and roughness was plenty to account for the sticking, so I'd say you are probably safe to trust that the construction is solid enough not to need them.
    Regards,
    Fred Sturm
    "When I smell a flower, I don't think about how it was cultivated. I like to listen to music the same way." Mompou









  • 3.  RE: Neupert progress: brass slides

    Registered Piano Technician
    Posted 03-02-2020 10:41
    So far so good. Installed the slides this morning, they are moving and returning freely - but that's without string tension. Before cleaning, polishing, sanding, etc. even without tension, the return spring wasn't pushing the 8' slide back. And it's a damned strong spring - I had one helluva time reinstalling it, it's held in place by its own tension... Let's see what happens with string tension. The hitchpin rails are glued and screwed down - it'll be a few days before I attempt to bring it up to pitch, maybe even next week...

    ------------------------------
    Israel Stein RPT
    P.O. Box 68141
    Jerusalem, Israel 9168002
    510-558-0777
    istein248@gmail.com
    ------------------------------



  • 4.  RE: Neupert progress: brass slides

    Registered Piano Technician
    Posted 03-09-2020 06:25
    Well, the bad news is that with the strings at tension (A=415 hz.) the slides get immobilized. When the tension is slackened somewhat on one of the string choirs, the 4' slide (operated by a knee lever) becomes mobile, the 8' slide remauns stuck. The good news is that the hitchpin rail repairs appear to be holding. The owner of the instrument casually dropped the bitofinformation that she never knew how to move the slides, and back when she was still playing the harpsichord way back when in New York she always had both registers "on". So they could have been "frozen" long before the instrument was dropped. It's kinda hard to tune the thing, though, withuout being able to kill the 4' register...

    Oh well... Don't know if it's worthwhile to mess with this Neupert any more...



    ------------------------------
    Israel Stein RPT
    P.O. Box 68141
    Jerusalem, Israel 9168002
    510-558-0777
    istein248@gmail.com
    ------------------------------