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Thread: Newbie clavichord build

  1. #1
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    Newbie clavichord build

    I recently retired and woodworking has always been something that I wanted to have more time for but I was unable to make time for it. My woodworking before the clavichord revolved around home renovation; building shelves, trim work, a mantle, a walk in pantry and a handful of typical projects like small boxes for gifts.

    I am not a musician but, I did restring an upright piano once. Iím that guy. I do have a brother that is an accomplished musician and a composer. The composer brother is the recipient of the small wooden boxes. He uses them to store small music things. He thinks that because I can make a small box, I should be able to make a clavichord. I didnít know what a clavichord was, but I am a sucker for a challenge. (Thatís why I restrung the piano)

    After doing some research, finding your forum, reading and rereading Phillip Allenís thread, I decided to accept my brotherís challenge. The clavichord build is clearly more complex and exacting than anything I have previously attempted, but what I will learn along the way will define my success.

    I told my brother I couldnít make the unfretted clavichord he wants and that I needed to start smaller. Fretted: fewer keys, fewer strings, smaller and lighter. He gives up discordant notes and I get a more manageable project.

    I chose the TD3 from the Friends of St Ceciliaís. The TD3 is triple-fretted, unsigned, undated but probably from Germany between 1690 and 1700.

    As of this post, I have a good portion of the casework complete and am starting on the interior. Because I am a rookie I am susceptible to rookie mistakes. My first rookie mistake is I purchased the Ĺ scale drawing. (I wasnít all in on the project when I ordered the drawing.) I have questions and I hope that some of you may be able to offer some thoughts so I can spend more time building and less time pondering.

    I will post my progress photos and questions.
    Attached Images Attached Images

  2. #2
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    20190202_150617.jpg
    I glued up some wide poplar boards for the base. When I ripped the baseboard to width it developed a bow. Unsatisfied with a bowed base, and concerned about cost, I cut the base into 1 Ĺ inch strips and glued it back together like a big cutting board. Not pretty but flat. Too wide to go through my planer so I bought a couple of hand planes and tried to learn my first new technique.
    20190207_161217.jpg

    Cut the case perimeter walnut boards to length
    20190203_190422.jpg

    Resaw
    20190203_215241.jpg

    Make a box.
    20190216_134535.jpg
    Confession. I have never made a dovetail joint. Remember the thread title... "Newbie" I wasn't kidding. I want to learn how, but I didn't want to practice on this day. So I used a box joint.

    Using a spacer to keep the keywell the exact width and square during the gluing.
    20190212_125644.jpg

    Baseboard moulding cap.
    20190218_233317_HDR.jpg
    Confession. I have patience but I can be impatient. Once I cut the baseboard apart and glued it back together like a big breadboard I put aside any goal of building the clavichord "exactly" to the plan. I will try to do the best I can, hopefully improve, but not get too bogged down with authentic details. I used the only router bit I had for the baseboard moulding cap. After all, the original builder didn't sign it. When the camera gets this close I can see all the gaps and scratches and nicks.

    Looks better if i back up a few feet.
    20190218_232401.jpg

  3. #3
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    First Question...
    I am working on the left hitch pin block. The drawing shows the block 4mm above the baseboard. Did the builder not glue the hitch pin block to the baseboard because of expansion and contraction concerns? Am I risking failure by gluing the hitch pin block to the baseboard? What if I extend the hitch pin block all the way to the baseboard but only glue it to the case walls? The wrest pin block is the same design. The builder elevates it above the baseboard. Any thoughts?

    hitch pin rail
    20190131_133235.jpg

    wrest pin block
    20190131_133221.jpg

    Left hitch pin rail, pin rod stock, and testing some finishes.
    20190222_131337.jpg
    Last edited by Gregory Chandler; 02-23-2019 at 5:02 PM.

  4. #4
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    I will be following this post. So far you seem to know what you're doing -(not that I know anything about building an instrument).
    I would like to hear a clip of your build when completed!

    Bruce
    Epilog TT 35W, 2 LMI SE225CV's
    CorelDraw 4 through 11
    CarveWright
    paper and pencils

  5. #5
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    I answered the first question myself.
    This clavichord survived 300 years so don't mess with the structural design. I don't know why he elevated the hitch pin block 4mm, I can't ask him. My solution was to make a 4mm floor for the tool compartment to support the near end of the hitch pin rail and I can use a 4mm spacer on the far end to hold things level until I glue it into place. The tool compartment looks better with the walnut floor.
    20190223_222223.jpg

  6. #6
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    A little off topic but I had some excitement this morning while ripping a board to make the soundboard support. (aka mousehole board)
    I needed to reduce the thickness of my stock so I set the blade a little less than 1/2 way up the board. I was going to make one pass, flip it end for end, make another pass, then finish the last bit in the middle with the band saw. Then I could smooth it with a hand plane. Seemed like a pretty safe plan.
    So I'm pushing the board along, the blade is completely enclosed in the wood, and all of a sudden the saw makes a small bang, stops instantly, some kind of smell and I feel like something has touched my finger.
    Apparently the waste part of the cut was thinner than I had realized and the little bit of side pressure that my ring finger was applying to keep the board against the fence, was enough to cause the wood to deflect, making a hole in the wood and allowing my finger to touch the blade.
    A few years ago I purchased the SawStop table saw. For those that are not familiar with it... The saw has a technology that can sense your finger touching the blade. Within milliseconds and just a tooth or two, it fires an aluminum block into the blade, not only instantly stopping the blade but pulling it below the surface. It ruins the blade and the mechanism but you get to keep your finger. After collecting my thoughts, I drove down to my local wood store (Hardwood Connection in Sycamore, IL) picked up another blade and another "cartridge" and was able to finish my mousehole board. My finger only lost a tiny bit of skin. So I will count this as a good day.
    20190302_100744.jpg
    20190302_125843.jpg20190302_101920.jpg
    Last edited by Gregory Chandler; 03-03-2019 at 12:06 AM.

  7. #7
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    The back rail and the left sound board support (aka mousehole board) are in place. The drawing specified the builder had used pine but I didn't have any decent pine. I did have a lightweight board from a 100 year old piano. I'm not sure what kind of wood but possibly red elm so I made those pieces from the red elm. The "red elm" board rips nicely but wanted to tear when I bored the hole and made cross grain cuts.
    I was not pleased with the look of the poplar strip baseboard. Almost all of the baseboard is hidden but some will be visible between the key tails and over by the tool box. With the walnut and brass and basswood for the key levers and whatever color felt, I didn't want the poplar strips to be a distraction. I decided to try dark colored milk paint. Not sure if it was the best solution but I applied a couple of coats then sanded it back until I began exposing grain and wood texture. The strip of poplar without paint is where the balance rail will go. Unfortunately, the mousehole board will be largely hidden. It was a lot of work.
    20190303_150418.jpg

  8. #8
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    The key lever guide method for this clavichord uses thin wooden wafers glued into the end of the key tails. The wafer sides up and down in a slot that is cut into the "rack" that sits on top of the back rail. I have the the rack cut to size and today's goal was to begin marking the slot locations. The half size drawing I purchased has few dimensions, most everything needs to measured on the drawing then doubled. After working with a magnifying glass for an hour, I determined that I really need to have the full size drawing. My opportunity for error is too great and the ability to correct an incorrectly cut slot after the rack is glued into place, is problematic. So I ordered a full size drawing today. The drawing comes from Scotland. Last time it required nearly a month to arrive so I will put the rack aside and work on the pieces that are not as critical or can be measured with more confidence.
    20190306_191415.jpg

  9. #9
    Quote Originally Posted by Gregory Chandler View Post
    First Question...
    I am working on the left hitch pin block. The drawing shows the block 4mm above the baseboard. Did the builder not glue the hitch pin block to the baseboard because of expansion and contraction concerns? Am I risking failure by gluing the hitch pin block to the baseboard? What if I extend the hitch pin block all the way to the baseboard but only glue it to the case walls? The wrest pin block is the same design. The builder elevates it above the baseboard. Any thoughts?
    What is difficult on with drawings on old instruments like this, is that you are frequently uncertain what state the drawing represents of the instrument. Is it an extrapolation of what the draftsman thought the instrument looked like when it was built (which will contain assumptions as to that state which may or may not be correct). Is it a rendering of what the instrument looks like now, after 300 years of case distortion caused by string tension, repairs and general degradation over the years (broken joints, case compressed across the stringband, changes by well meaning but clueless early 20th century restorers). Or some hybrid, maybe the instrument minus repairs at some point, or surmised with some but not all repairs. Did they take the instrument apart, did they x ray it, did the do a photo and correct for optical distortion, was it direct read?

    You get the basic idea. Historical instrument drawings are at best a guide as to what to build. There are so many unknowns as to what the original instrument looked like and what the intent of the builder was. This is very different from the plans that most woodworkers are used to having, which represent a new object to be rendered. It is possible that that the hitch pin block was originally glued to the base but separated due to shrinkage or the cross grain joint you are rightly worried about. It is equally possible that the block wasn't glued because of cross grain movement.

    In general instrument builders of the time ignored cross grain movement and other things that would be considered standard woodworking practice today. Part of that is because the climate of Europe where these instruments were built and used does not have the climatic extremes of North America (especially mid-west USA) and things like wood movement aren't as problematic. The other reason is the acoustic requirements of instruments often require violations of basic woodworking practice, like long cross grain joints between the soundboard and frame.

  10. #10
    Proper operation of a clavichord requires two things: 1. The keys work correctly and smoothly, and 2. The tangents are in the correct position relative to the stringband (more is required, but this is just on the keyboard )

    1). As far getting the keys to work correctly, either the keysheet needs to be marked out from the rack or the rack need to be marked out from the keysheet. On a clavichord, the keys are cut out from a solid sheet of wood made of flat sawn pieces. A lot North American makers use basswood for historic keyboards as it is stable, easy to work, readily available in good quality, and cheap in most places. Sugar pine, poplar, and other woods are also used; the main thing is it needs to be a very stable wood in service. The reason for flat sawn is that if the keys warp, they warp up and down rather than side to side, which would cause the keys to jam.

    For what you are doing, marking the rack from the drawing, and then cutting it, and then marking the keys from the rack is probably the easiest order of events. Also note that when making the keyboard, the balance pin holes are drilled before cutting the keys apart. They keysheet is nailed to the balance rail with a few brads and the holes drilled into both the keysheet and the balance rail at the same time. This assures that the balance pins will be in the right place for both rail and key. Usually the keyplates are glued on before sawing out the keyboard as well. The sharps are glued on after the keys are fitting and moving, so they can be glued centered on the key.

    2). For the tangents, you have some, but not a lot leeway in that they can be bent a little each way. This is even more important on a fretted clavichord where a string is more than one note and you can't compensate for position by changing string tension. This might be the point to be sure your brother knows that the temperament of the instrument is set by the position of the tangents, and can't just be set (or changed) by tuning the strings. It is likely the instrument is set in some kind of historic unequal temperament, which sounds wonderful for period music, but may take a little getting used after only hearing only equal temperament from a keyboard.

    Not sure if you have gotten to the point of needing strings, pins, tangents, etc, but the two North American suppliers of historic keyboard materials are The Instrument workshop (fortepiano.com) and Zuckermann Harpsichords (zhi.net) Hubbard may or may not be still in business.

  11. #11
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    20190312_000140.jpg

    Thank you for all the thoughtful information. The clavichord project is addicting. The precision is challenging but hopefully will make me a better woodworker.
    I was planning on drilling the balance pin holes with the keyboard slab tacked into place just as you suggested.

    I wasn't sure if I wanted to glue the touchplates on to the slab before cutting apart the keys. My thinking is, if my saw blade kerf runs a little wide or wanders I would not be messing up the touch plates. I could even veneer the side of a key if necessary before attaching the touchplates. It just seems like I could achieve a more uniform and smaller gap if the touchplates go on after. I have not read any discussion of why the touchpads are glued on before the keys are cut apart.

    In the photo the numbers at the top represent the distance between the bridge pin and the tangent. On the key tails you can see the position of the tangent. Because of the fretted design you can also see some of the tangents are very close to the edge of the key. Is it possible to insert the tangent so close to the edge of the key tail without the key splitting? Or is the tangent base actually closer to the middle of the keytail and the top of the tangent is "bent" to achieve the correct distance/interval? Aesthetically, I would rather have the tangents vertical and would go to great lengths with pre drilling to ensure the key doesn't split while planting the tangent.

    I already purchased zither pins to be used in place of the wrest pins. I purchased nickel plated desk pins for the balance pins. For the tangents I purchased brass bar stock. None of the above are period authentic, but hopefully will help me be successful and save a few dollars on this first attempt.

  12. #12
    Gregory Chandler,

    Building a clavichord from plans is something I've long wanted to do, having completed a small Zuckermann fretted kit about 30 years ago. I attended a clavichord symposium in Italy in 1993 and was inspired by the range and quality of instruments displayed and used in recitals in a fantastically atmospheric 12th Century church. One of the makers displayed a pedal clavichord in which an organ format pedalboard was made that functioned in the same way as a keyed clavichord. The strings were twice as long for longer sustain. Clavichords were often used by organists for practice and some organ builders, notably Gottfried Silbermann, also made clavichords and C.P.E Bach even wrote Farewell to My Silbermann Clavichord":

    https://www.youtube.com/watch?v=KbTU...t_radio=1&t=63

    Andrew Seemann has very good comments and suggestions.

    I would add that, given the time necessary to make large numbers of pins and tangents, consider ordering from Zuckermann:

    https://www.zhi.net/parts/

    In making the keyboard, any operation that can be done with the keyboard in plank form and before cutting the keys apart- drilling the pins, drilling the holes for the tangents, cutting the slots for the rear guide slips- the better. If you haven't done any of these operations yet, consider:

    1. Take the keyboard plan to an architects'/engineers' blueprinters, have them accurately scale it 1:1. Check the accuracy at the printers before accepting the enlargement.

    2. Glue the full scale print onto the keyboard plank and the guide rack which should be finish dimension. Set the guide rack at the appropriate distance from the back of the key levers.

    3. Set the keyboard plank on the finished balance rail and position blocks so the keyboard plank is completely level.

    4. With this setup, drill all the various holes including for the tangents.

    5. Scribe the positions of the rack and key end slots through the paper.

    6. Cut the rear rack section of the plan off so the guide slots may be accurately cut to width and very accurately vertically.

    This approach helps guarantee that everything to align and operate without binding, even if the balance pin is off a couple of mm, the key lever to balance pins and rear guide slips to rear guide rack are still all in the proper relative positions.

    Warning, clavichords are addictive and as soon as this one is finished, the next one will be in the planning stages. Consider in the next one, using Sitka Spruce for the soundboard which is available as a soundboard material for all kinds of stringed instruments. I don't know this company, but this is the general idea: https://alaskawoods.com

    I look to seeing further developments.

    Alan

    Clavichord TL_keyboard.jpg
    Zuckermann Fretted 1985
    Last edited by Alan Caro; 03-13-2019 at 5:39 PM. Reason: Dyslexia

  13. #13
    The tangents on most clavichords that I have seen (not a lot mind you) have been somewhat triangular in that they taper towards the base, so there isn't as much going into the wood. Full disclosure, I'n not as up on clavichords as I am on harpsichords and spinets, although both instruments are pretty similar until you get to the tangent vs jack part.

    Purchasing tangents from ZHI wouldn't be a bad idea, although they aren't cheap. If you order them by phone, they probably would be willing to tell you how to property install them. They tend to be pretty helpful (especially if you are buying stuff from them ) If you are adventurous you could try ordering from one of the European firms that supply them; they may be cheaper there, although shipping may cancel the savings.

    You will want to get wire from ZHI or Instrument Workshop though; modern wire is too hard had has too high tensile strength for historic instruments. I just ordered a bunch of brass from IW for my current spinet project.

    Also, check out the below websites. Peter is one of the top clavichord makers in the world and has a lot of good info. The HPSCHD-L is a email subscriber list. The archives are searchable by anyone have a lot of good info in them. Many of the top makers and historical keyboard players are on the list. You can also join the list and ask questions. They tend to be pretty tolerant of newbies (at least they are with me) although some folks occasionally can be a little crotchety. Just don't go talking about a lot of theories on how to build an instrument without having built any And don't talk about glue. They are a little crazy about glue.

    http://www.peter-bavington.co.uk/main.htm#CONTENTS

    https://list.uiowa.edu/scripts/wa.exe?A0=HPSCHD-L

  14. #14
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    Soundboard and Bridge Question

    I had already purchased the soundboard wood from Alaska Woods when Alan posted so I accept his suggestion as an affirmation. The shipping was nearly as much as the wood so I purchased three sets. The two AA quality were $8.33 each and the AAA quality was $14.14. Shipping for all three was $15.28. I sent them a sketch of my soundboard and they were able to confirm I was choosing from the correct sizes. VERY prompt communication and service. I will start with the $8.33 board.

    20190317_144855.jpg

    First Question: I need to reduce the soundboard thickness from 4.5 to 5 mm to a final thickness of 3 mm (plus or minus .25 according to the measurements of the original) How do others do this?

    __________________

    I am about half way through my first attempt at the bridge. I used an awl to poke guide holes directly from a drawing copy glued to the wood stock. It may be as Andrew noted, I am using a historical instrument drawing, not a modern woodworkers plan. That and sometimes I literally miss the mark. I think I can do better but some advice from others can be helpful. I am not pleased with the bridge pin hole alignment. They wander instead of flowing smoothly along a line. The patch of sappy wood makes it look worse. I am considering making a jig for my second attempt. This bridge is straight for 2/3 and curved over the last 1/3. I am also considering doing most of the drilling and shaping then dry heat bend or steam bend the curved part.

    20190317_145030.jpg

    Second Question: What kind of techniques, sequencing, tools... do others use when making the bridge?

  15. #15
    Hi,
    Soundboards were (and are) typically thinned with a smoothing plane. A standard Bailey's #4 works quite well. Make sure the iron is sharp, as spruce has a proclivity to tear. You could also random orbit sand one side flat (the top) and then just do the thinning from the bottom. Then you don't have to worry about surface quality as much. The edges need to be even (no ridges) so you get good glue joint between the board and liners. Don't over-thin the soundboard. If you leave it a little too thick, it may just not be as loud. If you go to thin, the string tension may collapse the soundboard. Soundboard thinning skill is one of those things that comes with experience, and distinguishes the professionals from the rest of us.

    For the bridge, make sure to use a wood with nice even grain. Pearwood, cherry, and beech were popular historically, Pearwood does't exist as lumber in North America; beech is a little on the hard side but it works nicely. Cherry is probably the easiest to use as it is a little softer than beech, but mechanically and acoustically still works well. Your bridge doesn't have a lot of curve, so sawing out of a single piece or wood is probably fine, and likely what was done on the original (historical makers didn't tend to do anything the hard way). For marking the bridge, you probably could do a pinprick to mark the hole, and then adjust as needed. The important thing for bridge pins is that the string must only contact the pin before touching the top of the bridge, or else the note will sound false, due to the wood of the bridge damping the vibrations, rather than the vibrations being transferred through the bridge pin. You might need to move one of your marks to get the pin in proper position; that whole bit about the drawing being a guide

    The glue joint between the bridge and soundboard is important to do well. Clavichord bridges can be under a fair amount of sheer, and the joint needs to be tight, strong, and not creep. Historic makers used hot hide glue, but that is inconvenient and takes a lot of practice and skill to get to work right, though in theory it is the best choice. Franklin's liquid hide glue will work as long as it is fresh, Titebond 1 and 2 would probably work fine as well. White glues (Elmers, etc) have too much creep. For clamping, there are various techniques, one is drilling small holes for brads, putting a piece of softer wood or plywood under the soundboard, gluing the bridge, and then driving small brads through the holes and soundboard into the wood/plywood below to clamp the bridge to the soundboard.

    One bit of overall advice, don't be shy of remaking parts, other than the soundboard, most wood going into a clavichord, harpsichord, etc. is quite inexpensive and usually not worth salvaging something that isn't turning out right. On my spinet, I have remade every single piece at least once with the exception of the soundboard, including the entire case. The soundboard, I somehow got right the first time. The first case made a nice bonfire one evening. It is one of those things that after you make a part, then you know how you should have done it. Might as well take advantage of that knowledge then

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