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Zuckermann jacks

  • 1.  Zuckermann jacks

    Registered Piano Technician
    Posted 02-18-2015 23:20
    I've had a uptick in harpsichord business the past few years, mostly from people resuscitating old instruments from the 70s and 80s, either kits or instruments made by "no-name" makers (people who didn't make very many instruments, and who often made very quirky design decisions). A few months ago, it was an instrument that had jacks that had started cracking and disintegrating, bad plastic, so all new jacks.

    The two I have in the shop at the moment are somewhat interesting in their relationship to Zuckermann jacks. The first was built by a local Santa Fe builder in the 70s. He made most wooden things from scratch, but bought things like jacks. The jacks are nothing I have seen before, but I deduce they must be the early prototype of the jack Zuckermann uses today. They are white plastic with a square bottom, like some I am familiar with. They have the Zuckermann style tongue, in that the pivot and the spring are the same thing. What is different is the fact that they have a top adjustment screw, the tongue has mortises for both plectra and leather (slot and square), and the snap-in insertion into the jack body is triangular in shape. I'll post photos. Anyone else seen these? The problem, of course, is that replacement tongues are impossible, hence the real long term solution for the instrument is new jacks, a bit more expensive than this customer wants to go.

    The other instrument is a venerable 5' straight side "Z-Box," the plywood kit out of the 50s through early 70s. In this case, somebody made an attempt to do the jack conversion. However, they couldn't figure out how to thread the tongue around the cross bar that limits the spring/pivot. So they inserted them all backward, shoved in plectra, and couldn't figure out why it didn't work. Hence they donated it to the local symphony, which wants it working so they can either sell it or find it a home. Not too bad, just remove tongue, remove plectrum, reinsert each the right way around, voice. Better than a lot of bollixed jobs I have run across. I'll post photos of that as well, along with photos showing how you SHOULD insert those tongues, how to thread them (it isn't intuitive).

    -------------------------------------------
    Fred Sturm
    University of New Mexico
    fssturm@unm.edu
    http://fredsturm.net
    "When I smell a flower, I don't think about how it was cultivated. I like to listen to music the same way." -Federico Mompou
    -------------------------------------------


  • 2.  RE: Zuckermann jacks

    Registered Piano Technician
    Posted 02-19-2015 09:12

    That jack sounds like a Hubbard jack
    -------------------------------------------
    Douglas Laing
    Tuner/Technician
    Safety Harbor FL
    727-539-9602
    -------------------------------------------




  • 3.  RE: Zuckermann jacks

    Registered Piano Technician
    Posted 02-19-2015 10:13
    The photos of the white jack that I believe to be prototype Zuckermann seem to have had trouble processing for a good while, but they are finally up there. They are definitely not Hubbard (I know Hubbard jacks very well): they have the Zuckermann design of tongue, where the portion that holds the plectrum is on the top end of a thin strip of plastic (I assume Delrin), which is in turn attached to the jack body at its bottom. With the modern Zuckermann, it is brown, and the part that snaps into the jack is rounded. In this jack, the part is more or less triangular. 

    I have not experimented with trying to detach one. I assume it snaps in, but there is no simple means of removal. Modern Z jacks have a hole in the jack body, and you can insert a pin and press the tongue base out. I could drill a hole, but I have no replacement parts, so I am leaving well enough alone. None have broken in 38 years (instrument dated 1977), so they may have a few years left.
    Regards,
    Fred Sturm
    "I am only interested in music that is better than it can be played." Schnabel



    ------Original Message------


    That jack sounds like a Hubbard jack
    -------------------------------------------
    Douglas Laing
    Tuner/Technician
    Safety Harbor FL
    727-539-9602
    -------------------------------------------


    Original Message


  • 4.  RE: Zuckermann jacks

    Posted 07-04-2015 05:18

    For removing plectra from jacks I use a modified (in my lathe) pin in a centre-pin removal tool. By 'modified' I put the original pin in the chuck and filed it down in diameter until it was the same as the delrin plectra thickness. Good tool to have - very controllable.    Michael   UK

    ------------------------------
    Michael Gamble
    semi retired
    Brighton
    01273813612
    ------------------------------


    Original Message


  • 5.  RE: Zuckermann jacks

    Posted 07-04-2015 07:33
      |   view attached

    Photo of my modified centre-pin extracting tool for use as a H'chord Plectra extracting tool:    Michael   UK



    ------------------------------
    Michael Gamble
    semi retired
    Brighton
    01273813612
    ------------------------------


    Original Message


  • 6.  RE: Zuckermann jacks

    Registered Piano Technician
    Posted 07-04-2015 12:11

    Nice idea. You might want the tip of the pin to be slightly concave so it wouldn't slip off the plectrum. Generally when you need to do this, it has broken flush and has a ridge to it, so a rounded or even flat surface would tend to want to slip to one side of it.

    If the plectrum hasn't broken flush, you can grasp it about 1 - 2 mm forward of the tongue with pliers (with fairly refined jaws) and press it through - supporting the tongue well while you push. Once it is moved a bit through the mortise, you can grasp it from the other end.

    I always leave a nub about 1 mm long at the back of the tongue, so I can either advance the plectrum just a wee bit with my thumb nail in case I cut a bit too short or voice too weak. It also serves as something to grasp and pull the plectrum out.


    ------------------------------
    Fred Sturm
    University of New Mexico
    fssturm@unm.edu
    http://fredsturm.net
    http://www.artoftuning.com
    "We either make ourselves happy or miserable. The amount of work is the same." - Carlos Casteneda
    ------------------------------


    Original Message


  • 7.  RE: Zuckermann jacks

    Posted 07-05-2015 03:50

    Fred - with care, one can extract a plectra in most conditions with this modified centre pin removing plier. One thing to take into account is that plectra are tapered toward the plucking end. ergo one always approaches a removal by pushing from that end. Out the back way! If the plectra is very flimsy and is to be replaced, simply cut it off close to the tongue with centre pin cutters and then use my modified whotsit. In extremis this tool can also be used to push the plectra through the tongue a bit-at-a-time - for voicing purposes. I've devised many such tools as this for different purposes. I have even devised another plier to 'controlled-crimp' the curvature of a spring in situ. and that block for making unified hitch pin loops is just another one. Great fun isn't it when enjoying one's self!!   Here's a video of my son Maxim enjoying himself last Saturday playing the Viola with a Junior Youth Orchestra:

    https://www.youtube.com/watch?v=vg7xrE1Xj6c&feature=youtu.be 

    Michael    UK

    ------------------------------
    Michael Gamble
    semi retired
    Brighton
    01273813612
    ------------------------------


    Original Message


  • 8.  RE: Zuckermann jacks

    Registered Piano Technician
    Posted 02-20-2015 17:48
    Hi Fred,

    If you were going to replace the jacks where would you purchase them? I have seen instances where replacing jacks would be the best thing to do but I could not find anything that would match the register holes. It would have meant a good deal of work either modifying the registers or replacing them.

    Some years ago I did have success replacing the jacks on a 70's Zuckermann virginal. I purchased the set from Instrument Workshop. FYI, it looks like the shop will be up and running again soon with new owners: http://www.fortepiano.com/

    Regards,
    Don

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




  • 9.  RE: Zuckermann jacks

    Registered Piano Technician
    Posted 02-20-2015 18:06
    I would probably replace with Hubbard. It is possible it would work with the existing lower register - I have done that successfully, with the jacks just slightly tilted but working just fine. But drilling a lower register isn't that much of a problem, just a matter of measuring, marking, center punching and drilling, certainly no worse than moving capstans. In this case the guide is attached in such a way that I can remove it easily, and use it as a partial template (move the holes out by a couple mm from existing holes). In any case, one can always attach a lower guide to the belly rail using angled brackets or something similar.

    I've given up hoping someone would produce new jacks with a square bottom centered to the jack body. It might happen, but not too likely. Not enough market to make it worthwhile to tool up. BTW, Richard Kingston told me his molds were shot, just wouldn't produce good enough products, and a new mold was WAY expensive.
    Regards,
    Fred Sturm
    "I am only interested in music that is better than it can be played." Schnabel



    ------Original Message------

    Hi Fred,

    If you were going to replace the jacks where would you purchase them? I have seen instances where replacing jacks would be the best thing to do but I could not find anything that would match the register holes. It would have meant a good deal of work either modifying the registers or replacing them.

    Some years ago I did have success replacing the jacks on a 70's Zuckermann virginal. I purchased the set from Instrument Workshop. FYI, it looks like the shop will be up and running again soon with new owners: http://www.fortepiano.com/

    Regards,
    Don

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


    Original Message


  • 10.  RE: Zuckermann jacks

    Registered Piano Technician
    Posted 02-20-2015 18:08
    Fred,

    Don's post reminded me of a job I did on a Zuckermann harpsichord back when I was still at the university.  At one point in Zuckerman's history they recommended replacing an older style jack with their updated version.  The old jack had a screw adjustment in the bottom. The new jack had no such screw adjustment, so I had to be careful to cut the length just right. But the main point I have is that Zuckerman provided a kit including new registers, jacks, and any other parts.  I think there were even bridge pins since the new jacks required some adjustment of the string spacing.  I plugged holes and redrilled the nut.  I may have actually had to plug and re drill the whole nut (bridge closest to the player).  I might have even installed a new set of strings.  Actually It was a fun project and resulted in a much improved instrument.  The main principle at work was that if you cut the jack to length perfectly one time, you'll never have to mess with length again.  The instrument swells and shrinks and carries the jack along with it so that the length puts the plectra in reasonably constant position in relation to the strings.  So if you can't find the right jack, you may have to do what I did and get the kit from Zuckermann.  This assumes that such a kit still exists.  It did 25 or so years ago.

    -------------------------------------------
    Richard West
    Oro Valley AZ
    520-395-0916
    440richard@gmail.com
    -------------------------------------------


    Original Message


  • 11.  RE: Zuckermann jacks

    Registered Piano Technician
    Posted 02-20-2015 18:25
    I think they still sell that conversion kit. It is for a one register instrument, though, Setting up for two or three lower registers with slots is a bit problematic. I would just find it simpler to dill holes.

    The other brown jacks I posted were from one of those conversions - and whoever did it inserted the tongues backwards. I've done at least two of those conversions, probably more over the years. Which means I have quite an archive of the old style Zuckermann jacks for my heirs to dispose of on eBay at a great profit ;-)

    Cutting those jacks is fine, if you do it precisely. If you have a harpsichord with three registers, though, it can be troublesome to get them staggered in a refined way, especially if the harpsichordist wants a shallow dip (which they usually do). Not so easy to add material to the bottom. I FAR prefer having bottom screws in order to do refined staggering, which needs to take into account how stiff the plectra are and how far they extend under the string. The stiffer and farther, the more dip it takes to go through pluck, which means the stagger has to be farther apart. If you lighten up, by having less stiff and less underhang, you need less dip, so you need to pull them closer together. So re-staggering is something I do on a regular basis, as things do change (e.g., plectra get stiffer with work hardening).

    It's kind of like aftertouch: if you have enough excess aftertouch, the action will work fine and reliably, but the pianist might not like it very much. If you stagger far enough, with the jacks plucking a fair distance from one another, you have to have extra dip so they all get through pluck before you bottom out. It will all work and will be reliable, but they won't like it. At least the ones I work for won't.
    Regards,
    Fred Sturm
    University of New Mexico



    ------Original Message------

    Fred,

    Don's post reminded me of a job I did on a Zuckermann harpsichord back when I was still at the university.  At one point in Zuckerman's history they recommended replacing an older style jack with their updated version.  The old jack had a screw adjustment in the bottom. The new jack had no such screw adjustment, so I had to be careful to cut the length just right. But the main point I have is that Zuckerman provided a kit including new registers, jacks, and any other parts.  I think there were even bridge pins since the new jacks required some adjustment of the string spacing.  I plugged holes and redrilled the nut.  I may have actually had to plug and re drill the whole nut (bridge closest to the player).  I might have even installed a new set of strings.  Actually It was a fun project and resulted in a much improved instrument.  The main principle at work was that if you cut the jack to length perfectly one time, you'll never have to mess with length again.  The instrument swells and shrinks and carries the jack along with it so that the length puts the plectra in reasonably constant position in relation to the strings.  So if you can't find the right jack, you may have to do what I did and get the kit from Zuckermann.  This assumes that such a kit still exists.  It did 25 or so years ago.

    -------------------------------------------
    Richard West
    Oro Valley AZ
    520-395-0916
    440richard@gmail.com
    -------------------------------------------


    Original Message


  • 12.  RE: Zuckermann jacks

    Registered Piano Technician
    Posted 03-17-2015 12:29
    My customer gave the go ahead to work on the instrument, so I have dug a little more into it. The white jacks I suspected (with near certainty) were Zuckermann prototypes are indeed Zuckermann - once I looked closely with magnification, I noticed the name Zuckermann embossed across the top, with Pat Pending on the back. The tongues do pry out (using a tiny screwdriver to wedge it out from the back, screwdriver inserted in between the tongue's bottom and the body of the jack).

    Not a successful prototype, and I am going to struggle to see if I can make it work. The spring, which is part of the body of the tongue, is half again as thick as on the modern Z jack (0.021" vs 0.014"), and a bit wider as well. So getting the jacks to fall (plectra to "escape") is a real challenge: the springs are FAR too strong. I've been experimenting with various things, including drilling and adding a lead weight (from my stock of original Z jacks, the straight-side kits) - which wasn't enough. I tried thinning a spring and also trimming its width. 

    I was hoping to do a fairly modest job (getting it all playable and fairly even) using the existing plectra (which are celcon, therefore recent, and hardly voiced at all). Now I discover that those were all inserted upside down (curving downwards rather than up), which, of course, contributes to the trouble of getting the plectra below the strings. It seems that if I reverse the plectra, minimize the distance the plectra extend under the string (when on), weaken the springs the maximum possible while ensuring they will barely touch the adjustment screw, I may be able to make a working instrument out of it. 

    I don't think Zuckermann was successful in patenting the jack - at least a patent search didn't show it (Zuckermann, harpsichord jack, harpsichord tongue, etc as search terms) - though there is a jack with the same principle of tongue, the difference being that the tongue is part of the jack, not removable.

    Anyway, a bit of history uncovered. The instrument was made in Santa Fe in 1977, so I guess that is the time span for that jack. The later white jack with square bottom, that is more similar to the current jack, was from the early 1980s (at least the kit instrument I own which had such jacks dates from then). I guess the current brown one that is I-beam in cross section came around the mid to late 80s. 

    -------------------------------------------
    Fred Sturm
    University of New Mexico
    fssturm@unm.edu
    http://fredsturm.net
    "When I smell a flower, I don't think about how it was cultivated. I like to listen to music the same way." -Federico Mompou
    -------------------------------------------




  • 13.  RE: Zuckermann jacks

    Posted 11-03-2021 14:32
    I know this reply is a bit late (by nearly seven years), but my Zuckermann harpsichord has these same exact jacks and tongues.  But rather than getting a complete new set of jacks, I decided to do a bit of engineering and modify these to fit a more traditional style of tongue. 
    Modified Zuckermann jack.
    Modified Zuckermann jack.


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    Andre Hut
    Music Hut
    PARKER CO
    720-870-5523
    ------------------------------