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Thread: Newbie clavichord build

  1. #16
    Join Date
    Dec 2018
    Location
    Illinois
    Posts
    13
    The full size drawing arrived from Scotland and I pinned it to the wall near the garage. My wife says I canít hang it in the living room. I canít overstate how much easier working off a full size drawing is. The full size drawing also exposed some inaccuracies in measurements that are now glued firmly in place.
    20190420_130855.jpg




    The bridge was difficult for me. On the seventh attempt I had finally discovered a path, process and technique that addressed various failures on the previous six bridges. It still has flaws. I am pleased with the profile, it closely matches the drawing, the pins are aligned nicely except the one at the bend is tilted a bit out of vertical.
    20190420_124854.jpg


    To position the bridge onto the soundboard, I made a measuring stick. Using the lowest bass hitch pin as a reference (and the full size drawing) I marked the stick where a sampling of the bridge pins should be located. I did this twice. The first time was before installing the bridge pins or gluing the bridge. The second time was after gluing the bridge, after installing the bridge pins, and in preparation for the final placement of the soundboard.
    20190420_121344.jpg




    I pre drilled the wrest pin block holes using a drill press before gluing the pin block into place. (I glued the wrest pin block to the frame before installing the soundboard) After drilling the pilot holes, I removed a thin slice from the pin block and am using that as a guide to drill the holes through the soundboard with a cordless drill. Because the pin block is tight against the right side case wall, I should be very near dead center.
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    The soundboard mouldings are 6 mm x 2.5 mm. I used the band saw to rip strips, then I made a jig to hold the strips and used a hand plane to produce a group that were equal width and thickness.
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    I used a shooting board to cut the miters. These are so small that the table saw is not the best tool. (See previous post about table saw and fingers!)
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    I used some small sticks to apply pressure to the moulding while the glue dries.
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    The drawing specifies oak for the balance rail. On my first attempt, I made a cutting error that I was able to patch and there was a small section of tear out on the back side of the rail. It actually looked pretty nice and the imperfections were the kind that casual observers would not notice. But I knew they were there. I had a scrap piece of 6/4 hickory that allowed a no cost opportunity for no regrets. Using the oak rail as my guide (it fit perfectly) I was able to make the hickory version without taking a single measurement. Having already worked out the various saw blade angles, it was fast, easy and fun making something with measuring.
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  2. #17
    Join Date
    Dec 2018
    Location
    Illinois
    Posts
    13
    It has been nearly 3 months since my last post. Partly due to the demands of spring and summer yard work, and partly due to not knowing how to accomplish a step, the progress has been slow. I haven't given up. I will attach a few photos to show you where I am as of today.
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    I glued up a basswood panel for the keys.

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    I made a template out of scrap to work out angles, spaces and achieve a good fit for my keywell.

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    I used the template to trace an outline, then cut out the keyboard blank.

    20190505_125412.jpg
    I marked the locations of the key guide slots on the rack.

    20190509_222654.jpg
    I cut the slots with the bandsaw.

    20190521_171509_HDR.jpg
    After marking the positions of the balance pin holes on the key blank, I wedged it firmly in place and drilled through the key blank into the balance rail. I also marked the position of the key guide tongues onto the key blank while everything was wedged tight.

    20190630_222120_HDR.jpg
    I attached the veneer cap to the rack. Marked the locations of the rear hitch pins. Set the drill press at a 15 degree angle to drill the holes for the pins. I used a dremel tool to cut off the pins then finished them with a small file and small fine sanding block.

    20190705_204919_HDR#1.jpg
    Sorry the photo is rotated... I glued the rack to the case.
    Last edited by Gregory Chandler; 07-21-2019 at 9:55 PM.

  3. #18
    Join Date
    Dec 2018
    Location
    Illinois
    Posts
    13
    20190707_202219_HDR.jpg
    I set the balance pins.

    20190713_201049_HDR.jpg
    Key lever pivot pads. I used 1/8 inch square leather shoelace.

    IMG_20190609_192027_158.jpg
    I bought a fancy fret saw and had a proud moment when I cut out my first key. The feeling of pride turned to despair when I discovered I did not have the skill to accurately cut the keys by hand. I botched the next two keys then stopped.

    IMG_20190617_235320_618.jpg
    I had an old scroll saw in the barn my dad had given me about 15 or 20 years ago. I had never used it and it was in poor condition. I cleaned it up, put a new cord on the motor, and put one of the fret saw blades in. It worked! (photo was from instagram) Time to cut some keys.

    20190721_212807.jpg
    I have been cutting the keys out in small groups. After each group is cut, I insert the key guide and elongate the pivot hole. Some adjustments are generally necessary to allow the key to travel up and down freely. I make these adjustments with each key in isolation. After all the keys are rough cut, I will attach the key tops and begin carving.
    Last edited by Gregory Chandler; 07-22-2019 at 12:27 AM. Reason: rotate photos

  4. #19
    Gregory Chandler,

    Congratulations on the progress and quality of work on the clavichord project. It takes very good visualization skills to create a keyboard instruments from plans especially without having to spent a lot of time with actual examples.

    The keyboard are particularly difficult to have operate smoothly, with quick response, fast return, and importantly, that are quiet. One of the other unique qualities of clavichord is the string gauges require experimentation as the relative springiness is important to the action; if the string is too taught, the tangent will bounce off, too loose and it will fell soft and the pitch will rise. Moving the point at which the string gauge changes is a possibility especially if the string gauge was specified for A-415 and the new instrument is using a modern A=435.

    Besides the fraction of a mm placement of the tangent necessary on a fretted instrument, the distance between the tangent and string is also important; too loose and it's too quiet, too far and it's difficult to play easily.

    Tangent placement is critical as it on a fretted instrument it will vary according to the temperament. Many 17th C. clavichords will have been meantone, whereas later 18th C. will have a version of equal temperament. For the tangent placement, mount the tangent of the lowest note of each string pair to it's plan location, and with a tuner, hold the next higher note's tangent in place according to plan, set the tuner for that note, pluck the string and move the tangent to where it's in tune in the temperament you're using. It's possible to bend the tangents some to tune the fretted notes, but if they're bent too far, the top surface is not in full contact to the string and it can sound a bit weaker or can buzz.

    Thanks again for the progress reports and I look forward to the next installment.

    Alan
    Last edited by Alan Caro; 07-29-2019 at 11:45 AM.

  5. #20
    Join Date
    Dec 2018
    Location
    Illinois
    Posts
    13
    Alan,

    Thank you for all the information. I have a few questions...

    How far does a key travel before the tangent makes contact with the string?

    I assume I should set the tangents at a depth so every key has the same amount of travel?
    20190731_010855.jpg
    My plan has a chart that shows that the distance from the levers to the tops of the tangents vary by 3mm from the bass section to the treble.

    The plan also shows the distance from the top of a representative tangent to the string as 6mm, but does that distance vary?

    I probably have a month of more of carving and key detailing before I am ready for stringing but would you recommend starting at the treble end and do one string pair at a time with the associated tangents before moving on to the next string pair? Or would you do all the stringing then work on the tangents?

    I have never seen (other than photos) or touched a clavichord, and my drawings are just drawings, not instructions. The suggestions and insights you and Andrew have shared are so helpful. Thank you!

    Greg

  6. #21
    Greg,

    The distance from the tangent to string is progressive, generally being closer in the bass and farther in the treble. This is another indicator of the role that the string tension plays in the action. The long and often brass strings in the bass are not as taught as the treble strings, so when pressing the key, the looser tension makes the apparent key depth larger and it feels less responsive. This happens on harpsichords too, but harpsichords are generally scaled further down in the bass : (that is the doubling of string length for each octave reaches a but lower and as the key pressure on harpsichords does not affect the volume of sound produced, it's not as noticeable. I'd suggest following the plan notes- that seems about right. I've played quite a few modern clavichords that increased the tangent to string distance up to 9-12mm to try and increase the volume, but I find them difficult to play.

    The feel of the action does take quite a lot of getting used to. No other keyboard instrument has that sensation. And of course, the quite amazing proportional control over the volume and the ability to produce vibrato and bend notes for effect isn't found on any other stringed keyboard instrument. This is the reason that learning the clavichord was so highly prized as it required an evenness of touch pressure not required on an organ or harpsichord. Clavichords are really amazingly elegant in terms of effective simplicity, considering the expressive control of a simple keylever on a balance rail with a vertical blade of brass as compared to up to 130+ parts in one note of a grand piano action.

    Not a lot of sound, but one quickly tunes into it. I attended a recital series with 120-150 people in a 12th C. church in northern Italy and the requirement to not make the slightest sound really drew the audience into participation in the event. Clavichords have an odd introspective and calming effect.

    In my view, recordings can help provide a further insight into the appropriate sound of a less familiar instrument like a clavichord.

    I recommend, particularly, this one of music by Froberger, performed by Thurston Dart:

    https://www.youtube.com/watch?v=wILVMuon6r4&t=595s

    Very expressive music that at the time could have only been realized on clavichord.

    And Dart's Bach French suites, here introduced by Dart:

    https://www.youtube.com/watch?v=pzI7rK7hwNc&t=858s

    Christopher Hogwood also recorded quite a lot on clavichord:

    https://www.youtube.com/watch?v=gcyPrOVYRVk

    Igor Kipnis, who I met in Princeton in 1973, and interviewed on the radio in 2000, recorded quite a bit on clavichord in addition to his usual harpsichord:

    https://www.youtube.com/watch?v=e-bV-Sm4aWs

    > listen at 27:45

    A lot of CPE Bach seems very suited to the clavichord and CPE was a promoter of it for learning:

    https://www.youtube.com/watch?v=1zOt-oBekls

    The clavichord videos by Win Winters- which include surprisingly successful selections of Beethoven (Beethoven did mention having a clavichord and there's is one in the museum of the Conservatoire de Paris that I've seen, claimed, probably spuriously to have been his) and


    What are your plans for the case finish?

    Alan
    Last edited by Alan Caro; 07-31-2019 at 7:06 PM.

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