Harpsichord

 View Only
Expand all | Collapse all

Gap Spacers for a Zuckermann

  • 1.  Gap Spacers for a Zuckermann

    Registered Piano Technician
    Posted 01-22-2019 20:19
    I am about to undertake a repair on a Zuckermann Flemish double; placing gap spacers between the wrestplank and the belly rail. This is a common solution to solve register freezing for many Zuckermann kit harpsichords but I have only done this procedure once many years ago. For the first time I used steel gap spacers but this time I'm going to make the spacers from scraps of beech laminate pinblock material. I spoke to Richard Auber at Zuckermann and he suggested a good plan on how to proceed. If there is anyone out there that has performed this procedure, it would be helpful if you could share your experience. The more I know the better the outcome of this repair!

    ------------------------------
    [Don] [McKechnie,] [RPT]
    [Piano Technician]
    [dmckech@ithaca.edu]
    [Home 607.277.7112]
    ------------------------------


  • 2.  RE: Gap Spacers for a Zuckermann

    Registered Piano Technician
    Posted 01-23-2019 14:27
    Following! Pics please (if you have time, etc)

    I read up some about Zuckermannwhen Fred posted that link just after he (Zuckermann!) passed away. Absolutely FACINATING man, and what a life!

    ------------------------------
    [Kevin] [Fortenberry] [RPT]
    [Staff Techician]
    [Texas Tech Univ]
    [Lubbock] [TX]
    [8067783962]
    ------------------------------



  • 3.  RE: Gap Spacers for a Zuckermann

    Registered Piano Technician
    Posted 01-23-2019 14:54
    My own experience of the gap squeezing the registers so they couldn't shift came from the soundboard having crept, presumably due to use of Titebond. The board had moved beyond the edge of the belly rail, and the hitchpin rail had moved from the bent side, presumably riding on top of the soundboard. I managed to remove the registers, filed/sanded the SB edge flush, replaced registers. 2 - 3 years later the problem recurred (I passed on attempting a fix, explaining what the problem was.

    The couple times I retrofit gap spacers, I used wood, and I filed the ends somewhat round so that I would be able to tap one end to straighten it, the other end being held in place (I think by a shallow groove I had chiseled in the belly or the pin block edge). It's been many years, so the details are fuzzy.. 

    I suppose another option would be to widen the gap a wee bit, possibly by driving wedges, as in one wedge supported by the bottom of the instrument, the other being driven from above. Just enough so that the ever so slightly over size spacer can be insinuated into place. The placement has to have been carefully chosen to avoid interfering with jacks.
    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









  • 4.  RE: Gap Spacers for a Zuckermann

    Registered Piano Technician
    Posted 01-23-2019 15:59
      |   view attached
    Thanks Fred for the tip on rounding the edges of the spacer. I have been thinking of applying a small amount of glue to the ends to make it easier to put the spacer in place. I will explore the possibility of chiseling a gap in the block or belly rail.

    When I did this procedure last time, I widened the gap a very little bit by using a homemade jack and a machinist jack. It worked but one has to be very careful to not push the gap too much with these jacks. ( see picture)

    It is interesting to note that this instrument had suffered from "cheek disease" so the owner sent it to Zuckermann for a fix around 2002. (This harpsichord was put together in 1975 in Boston. The same year I graduated from North Bennett!)  Again, this is another common problem on the early kits due to not enough bracing. At the shop they cut out some ports in the bottom and added more bracing. Richard told me to have a look inside to make sure everything looks solid with the bracing. Richard also said there is nothing recorded that shows gap spacers were put in during the repairs at the shop. That is something they would normally do so this will be another wait and see.

    Obviously this problem with the frozen registers could happen due to bracing issues. I do not think that is the case now but we shall see. The registers are working fine now but they will seize up in the summer according to the owner. So, it is possible that the soundboard swelling could be the issue. I will have to ask the owner if he remembers what glue he used.

    Wish me luck!

    ------------------------------
    [Don] [McKechnie,] [RPT]
    [Piano Technician]
    [dmckech@ithaca.edu]
    [Home 607.277.7112]
    ------------------------------



  • 5.  RE: Gap Spacers for a Zuckermann

    Registered Piano Technician
    Posted 01-23-2019 17:00
    You might also consider narrowing the registers a wee bit. 0.5 mm here and there adds up to real space. As long as everything is already out, why not, as a bit of extra insurance?
    Fred Sturm
    University of New Mexico
    fssturm@unm.edu
    http://fredsturm.net
    www.artoftuning.com
    "Practice makes permanent. (Only perfect practice makes perfect)."






  • 6.  RE: Gap Spacers for a Zuckermann

    Registered Piano Technician
    Posted 01-23-2019 17:57
    I have considered narrowing down the registers a bit. I will make that decision after I inspect. As this is an in home repair I'm not sure if I will have an adequate workspace to do the trimming. It will take more than an afternoon to do the whole job as regulating and voicing is also necessary. So, it may come down to taking the registers home for trimming.

    ------------------------------
    [Don] [McKechnie,] [RPT]
    [Piano Technician]
    [dmckech@ithaca.edu]
    [Home 607.277.7112]
    ------------------------------



  • 7.  RE: Gap Spacers for a Zuckermann

    Registered Piano Technician
    Posted 01-23-2019 18:32
    For in home, you could at least take a sanding block of some sort to each side of each register, maybe go through a few grits. The kind of thing I might take out to the car to do, if people are around. 

    Conceivably you could plane, if you can devise a way to hold it in place. I can picture on the porch or in in the driveway, butting up against a wall, planing a couple strokes from each direction, assuming the grain allows. Alternately, use a cabinet scraper. You could probably hold it in place by kneeling on it, and either pull towards yourself or push away.

    Or you could have a block of some sort with sandpaper glued to it, fixed in place in some fashion (clamped to some surface) and run the register across it. 

    Back at the shop would, of course, be more convenient, but there are always ways to improvise.
    Regards,
    Fred Sturm
    University of New Mexico






  • 8.  RE: Gap Spacers for a Zuckermann

    Registered Piano Technician
    Posted 01-23-2019 18:57

    Thanks for the suggestions Fred. If I do give it a go, it will not be outside tomorrow. 1 to 3" of snow expected! There might be some workspace in the garage.

     

    Don McKechnie, RPT

    dmckech@ithaca.edu

    607.277.7112






  • 9.  RE: Gap Spacers for a Zuckermann

    Registered Piano Technician
    Posted 01-25-2019 14:55

    I had my first session on the gap spacing repair on this Zuckermann. Interesting things were revealed! I wish I had the room at home in my workspace to do the work. It is not ideal doing this repair in a home.

    I had my gap spacers all ready to go but the wrestplank threw me a curve. The back end of the plank is not square to the top and bottom. There is an angle going downward towards the front. Of course, I made square gap spacers. As you will note from the pictures there are gap spacers. The two wood spacers are original and the aluminum spacer was added some time after the harpsichord was returned from its visit to the Zuckermann shop in 2002. I intend to add spacers in the treble and bass just for security. Fred, as you mentioned on your remembrance of a gap repair, there is a groove in the wrestplank for the original spacers.

    Note the pictures of the gap in the treble and bass ends. You can see how tight the gap is to the registers. Note especially the treble gap and the soundboard line. The soundboard line is quite uneven. When I removed the registers, it was obvious that the soundboard pushed forward a bit. By sanding the edge of the board and the belly rail I now have some space.

    Removing the strings was necessary to gain access to the gap. So far, I am finding that it is impossible to reuse the 4' strings in the high treble. The tuning pins are the very small tapered type without becket holes. The 8' strings are tightening up so that was a relief. If anyone has suggestions on how to tighten the original strings on the thin 4' strings I would appreciate the help.

    Note the picture of the treble side of the instrument. You can clearly see the cheek disease. You can see the repair for the cheek disease in the picture showing the brace that was added. Obviously, the case cannot be straightened out but the new brace has stabilized the instrument.



    ------------------------------
    [Don] [McKechnie,] [RPT]
    [Piano Technician]
    [dmckech@ithaca.edu]
    [Home 607.277.7112]
    ------------------------------



  • 10.  RE: Gap Spacers for a Zuckermann

    Posted 02-01-2019 12:02
    We have to convince people that these kind of repairs must be undertaken in the workshop.  I don't suppose you can simply loosen strings to replace gap spacers.  That would make things easier. 

    Frank French
    970-644-7207








  • 11.  RE: Gap Spacers for a Zuckermann

    Registered Piano Technician
    Posted 02-01-2019 14:10

    Frank, I agree that the work is best done in the workshop. Unfortunately I cannot take it in just now and the customer would like the work done sooner rather than much later. Just bad timing.

     

    Given the type of tuning pins used on this instrument, it is not possible to just take down the tension just a bit to get the strings out of the way. The coils will come loose and in the case of the thinnest strings, they are next to impossible to get tight again; at least in any way I am able come up with.

     

    Besides adding gap spacers, the edge of the soundboard and the belly rail need filing. I believe that is the current culprit in seizing the registers. I want to put gap spacers in the treble and bass just for insurance.

     

    Don McKechnie, RPT

    dmckech@ithaca.edu

    607.277.7112






  • 12.  RE: Gap Spacers for a Zuckermann

    Registered Piano Technician
    Posted 03-27-2019 10:36
      |   view attached
    I just realized that I have been remiss in posting the outcome of this project. Basically, it all went well! Attached is a picture showing all the gap spacers. With so many in place, I do not expect to get a call in the summer that the registers are tight again. Richard Auber convinced me to try taking just a bit off the sides of the registers using my table saw. I was a bit nervous about that but it worked. It certainly is extra insurance against the registers seizing again. The owner was very pleased with the final result. After I regulated and voiced the instrument he is now considering keeping the instrument instead of selling as originally planned.

    ------------------------------
    [Don] [McKechnie,] [RPT]
    [Piano Technician]
    [dmckech@ithaca.edu]
    [Home 607.277.7112]
    ------------------------------



  • 13.  RE: Gap Spacers for a Zuckermann

    Registered Piano Technician
    Posted 03-27-2019 11:16
    As it happens, I traveled up to Taos (2 1/2 hours each way) to do a sight unseen all day "get it working again" job. I found frozen registers, which I attributed to its move from Arkansas a few years back (didn't seem to be any sign of creeping soundboard over the belly rail). The real challenge was prying them out of the gap so I could remove them - start one end of one register, pry it up enough that I could get something in to wedge it that far open, gradually move upward. Took probably 30 minutes to do that. Not fun.

    I then took each register outside and used those metal sanding files from Pianotek to reduce them a bit. It really didn't take that much, hand work starting with coarse, finishing with fine. And the job turned out well. The registers were also warped a bit, which I was able to address adequately. Nicer to have it in the shop, but sometimes you just have to do with what you have available.






  • 14.  RE: Gap Spacers for a Zuckermann

    Registered Piano Technician
    Posted 03-27-2019 21:14
    Fred,

    It was hard to get the registers out of the instrument on my project. The 8' register was a bit warped as well. When I ran the register through the table saw it took a bit more wood off the treble end but not enough to present a problem. I did consider using the Pianotek files but Richard convinced me to try the table saw. Should I have a similar situation like yours I now know it can be done successfully. I certainly have more confidence now that I have this repair experience behind me.

    Best,
    Don

    ------------------------------
    [Don] [McKechnie,] [RPT]
    [Piano Technician]
    [dmckech@ithaca.edu]
    [Home 607.277.7112]
    ------------------------------