A Clavichord Build

[Phillip J Allen]

It was back in June of 2016 that I asked this forum on suggestions for a first clavichord build project. The first week in January of 2016 I got the plans for the Christian Gottlob Hubert 1784 (serial 8604) from St Cecilia. I began the building process in August of 2016. I decided to build the instrument casework from ash not the original cherry since I had some well seasoned ash on hand.

The build began with resawing. I have since upgraded my frame-saw "bandsaw blade" with proper re-sawing blade and WOW did it work faster....of course I had already completed on the tough re-sawing with a bandsaw blade.
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Initially I made a base of some crappy blue stained pine that I had sitting around but after a month it warped & twisted something fierce so I had to pull it off and replace it with some popular that went out and purchased. At the time of this photo my little chocolate lab Deacon was only 4 months old. He is definitely too big to sit in the clavichord now!
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Gluing the base on took a bit of skill to get it done quickly before the animal hide glue cooled! I slightly modified the one mouse hole design from the plans and made it from 4 smaller scraps of oak. It seemed like the easiest way.

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Well, 8 photos are the limit per post so, to-be-continued!

Phil

[Phillip J Allen]

Time to plane & re-saw some more ash for the top. Mortising the top for frame and panel construction almost two weeks with a 1/4 inch mortising chisel. I was very careful to not blow out the sides. I think for the second I will use a drill to start the mortises.
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I have made more than a few frame and panels before this but this was the first one in which I needed the french miters. It was a bit tricky and I am not quite content with my final product but all that matters is the next one will be better!
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I the returned to the casework. The front of the key-well was glued into the place and the back-board was put into place without much problems. The back board was two pine boards laminated together to get the proper thickness and then with an ash board laminated on top for which will eventually get drilled for the pins.
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So far so good!

Phil

[Phillip J Allen]

Now I started to layout the position of pine & oak wrest planks underneath the sound-board.
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Another slight modification from the plans, I decided to half lap the oak top of the wrest plank to make it stronger. This oak wrest plank will later be drilled for the tuning pegs.
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Fitting the pine/oak laminated balance beam required a bit of care since it is not parallel to the front of the carcass!
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Gluing all these things onto the inside of the carcass required some thin wooded braces using the wood shop ceiling!
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And finally the rest of the of the soundboard support was glued into place.
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Phil

[Phillip J Allen]

All of the finer/smaller molding I made using some hollows and rounds. Unfortunately I must have forgotten to photograph. But for the larger lower carcass molding I decided to make a custom cutter for my Stanley 55! A man does have to use his toys or otherwise he cannot buy more!
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These are the top moldings made with hollows & rounds. I discovered making custom Stanley 55 cutters is not as much fun as I thought they would be. And making Ash molding with a #55 is challenging to say the least....
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Gluing the moldings on with hide glue and no nails wasn't too bad.
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Phil

[Phillip J Allen]

I made and glued the top moldings slightly over-sized/wide so I could then trim them perfectly flush with the carcass.
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Next stop the key-plank!

Phil

[Phillip J Allen]

The first step of the key-plank/keyboard construction is the arcades....those little spiral decorations on the front of the keys. I took an old 3/4 inch spade bit and started filing.
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I then cut two strips of black walnut that I harvested from firewood and then lightly glued them together.
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I tried to drill the arcades with an egg-beater drill but wasn't really happy with the results so I the went to my shopsmith drill press. Sorry neanderthals out there!
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And then add a bit of water and heat and separate the two pieces of arcade key-fronts!
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Phil

[Phillip J Allen]

The keyboard/key-plank was made from basswood.....or lime wood as the British plans call it! So a plank was procured, jointed, cut, glued and then planned to thickness.
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Then some more re-sawing of black walnut for the key touch pads
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This walnut veneer was then glued into a long wise strip and affixed to a rabbit planed into the front of the key-plank.
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The key-plank was then flipped over and then the arcades were glued onto the front underneath the front touch pads.
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Phil

[Phillip J Allen]

More walnut firewood veneer was re-saw for the back half of the key touch plates and glued down. I hammered sewing pins into the basswood to keep them properly aligned during gluing and clamping.
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Phil

[Phillip J Allen]

Before properly fitting and cutting up the key-plank I switch gears and made the sound board and bridge. I had some very lovely fine-grained redwood that I salvaged from my friends 1951 porch ceiling. So it was well aged out here in Colorado! I wasn't too worried about the sound quality since this is a clavichord not a violin. And there are more than one reference to old time clavichord makers using various woods for the sound board. The bridge was cut from a plank of English sycamore which so far was the most extensive thing that I have had to purchase for this project.
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gluing the bridge to the sound board required a few cauls.
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And now I flipped the sound board over and affixed the soundboard bars made of redwood
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Now the soundboard was glued into place. Again sorry I don't have any photos. It was a bit of a frantic glue up so I think that I just forgot to photograph it.
But after gluing in some fine molding around the boarder of the sound board it was time to drill the tuning peg holes using an egg-beater drill and an angled guide block.
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And finally I put a thin coat of shallac on the sound board. Next time I will try and egg-white mixture for sealing the soundboard and I will also try to remember to to the bottom of the soundboard as well before I glue the thing in place!
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Phil

[Phillip J Allen]

Now back to the keyboard. I used a marking gauge and the corner of of a file to make the fine lines across the top of the front of the touch pads.
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The key ends are partially cut first with a rip back saw.
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The key-plank is then placed into the carcass and temporarily affixed/positioned into place with nails in the pre-drilled balance pin holes.
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Then all the balance pin hole locations are marked into the balance rail before the plank is cut up into individual keys. Then the guide pin locations are marked using the key-plank saw kerfs as a guide.
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Now using a fret saw, a frame saw.....and okay a band-saw I cut the keys apart. Sorry for the band saw I got lazy and my frame saw cutting technique is not as good as I wish...
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Phil

[Phillip J Allen]

Now that the "key-plank" is no more and all I have is separate "keys", it is now time to start the carving of the key-top arches.
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Now the little oval shaped balance pins were hammered into place. They were also real fun to file to shape.
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And then the oval back-rail guide pins were hammered in place.
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The balance pin holes in the key board are broader a the top and round at the bottom to allow the see-saw action of the keys so a wedge was filed from a steel rod. This was then hammered into the balance pin pilot hole previously drilled. I should have made these punched holes before I cut of the the key-plank. Oh well live and learn.
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Phil

[Phillip J Allen]

Now that they keys are in and roughly fitted:
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It is time to turn the natural keys over and carve the underside to remove some weight from the front of the keys.
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This is my first time working with basswood. It is very nice to carve! This process went a lot easier than I though it would.

Now I cut & planed to size some maple that I also harvested from local firewood for the accidental keys! And then carved the underside of the front of the accidental keys to remove weight.
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Phil

[Phillip J Allen]

Now it was time to trim the back ends of the keys slightly and glue some fine leather around the tips so they fit properly without too much play between the guide pins. This took a bit of fiddling to get right and I believe that it will require more work at a later date.
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They key touch pads were then coated and 5-6 coats of boiled linseed oil and are really starting to look store bought!
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Hay it is really starting to look like a clavichord!

Phil

[Phillip J Allen]

I am mainly a woodworker and I just recently got a small craftsman 109-21270 metal lathe. I decided to make my own tuning wrench as my first metal turning project. The handle I made out of ash and it required a single off-center turn to form the shape. It all came out acceptable.
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I then took 16 penny nails and made the tuning pegs. I finished the tuning pegs by gun bluing them. I should have used the thicker "common" 16P nails not the slightly thinner "box" 16P nails. After pounding the tops of 78 tuning pegs I wasn't in the mood to start over again.
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Also please notice my forethought. I made the tuning wrench first and then made the tuning pegs so I could make sure they all fit the wrench! Sometime I get lucky!

For most of the brass hinges I was able to source some appropriate ones from the hardware store without any problem. But I couldn't find any nice brass lid hinges for a 1cm thick lid. Accept some very expensive ones from a harpsichord parts dealer in Europe and I felt US$60.00 per hinge was a bit too pricey for me. So I made my own.
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Making your own brass hinges wasn't too hard but I must say I don't think that I want to make a living making these!

Phil

[Phillip J Allen]

Now it was time to put felt on the back rail to cushion the backs of the keys when they fall down. The red felt for the back rail & the listing cloth strips that I will install later were pool table felt. A a strip of paper was glued between the tuning pegs which records which note the tuning peg should be.
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Now it was time to start the stringing process.
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The last 22 lower bass strings are open over-wound strings. Copper wire spiraled down the brass string. These are difficult to find and typically expensive. So I had to build a string winding lathe.
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It wasn't too hard to build but as you can see it only has a hand crank. A made my girl friend turn the crank. She really loves me.......nobody is really sure why. For the next instrument I will put a sewing machine motor on it otherwise I will be living alone and lonely.......

Here are the strings on the clavichord!
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Phil

[Phillip J Allen]

I then purchased sheets of brass and cut out the wedge-shaped tangents. For the lower 11 bass keys for the 22 over-wound strings the tips were folded over so they didn't get caught between the copper overwindings.
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I drilled a small pilot hole and clamped them to make sure they didn't split the thin delicate key ends. It was a little nerve racking but no major problems!

A few years back I remodeled my 1950's house bathroom and removed the lead toilet pipe. This old lead pipe I then melted down with a blow torch and made some 1/4 inch lead rod which was then used to add some back weight to the keys. The toilet never sang like this!
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Phil

[Phillip J Allen]

The entire carcass and lid were finished with 3 coats of hot boiled linseed oil and 3-4 coats of garnet shellac. I am really happy with the outcome and is sounds pretty good. I still need to complete some fine adjustment to the keys, i.e. voicing. But for the most part the instrument is done. As you can tell, Deacon my chocolate lab is now full size and is just too big to sit on the work bench or sit inside the clavichord!
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Thanks to everyone on the forum back in 2016 for all your suggestions to get started on this clavichord build. Getting started on this project would have been a lot harder without you all!

I guess not it is time to learn how to play it before I start on the second one! The second will be a lot easier now that I know what I am doing.

regards,

Phil

[Ernie Miller]

Really nice job on your instrument. A lot of people say a clavichord is easy to build, but it's not - at least it's not if you want it to actually play reliably. Be careful, instrument building can be addictive. In 1985, I built my one and only harpsichord. That was over 40 harpsichords ago.:)

[Alan Caro]

Phillip J Allen,

That's really extraordinarily good plan-reading, build sequence planning, and craftsmanship.

Clavichords pretend to be simple rectangular boxes on the exterior, but the design / layout, that is generated from the layout of the tangents creates a jumble of complex, parts, almost all of which are visible. Because the strings are angled to the longitudinal sides- except on the early projecting keyboard configuration, the anti- torsion efforts creates oddly shaped and surprisingly heavy structural parts having complex joinery.

And, previous to the machine age, if it didn't show, not much fuss was made over it. A Ruckers harpsichord keyboard shows what I would consider minimal attention to finish. However, with a clavichord, everything except the pinblock and structure under the soundboard is right in the player's face all the time. Clavichords have the triangular carving to the key levers, but a few examples have the keys without accidentals between: B/C and E/F where the tops are carved in a serpentine. The interior of many harpsichords have glue running out of structural joints, and Kirckman harpsichord had unfinished, unveneered straight sides, sometimes with with big knots in the planks. Clavichords were sometimes knocked out inexpensively- anonymous in-between projects for organ builders, but the signed instruments are still at a high level of finish.

I've not heard of a clavichord with a redwood soundboard, and am interested in the sonic results. As clavichords are so quiet, and the soundboard is glued onto the very heavy pinblock and case lining structure, the soundboard and ribbing pattern is surprisingly important. Hubert experimented with the soundboard bracing pattern to divide the sound board into resonant zones and to try and transfer as much vibration to the least encumbered zones.

Yes, really well done. I'll look forward to news of further progress.

Alan

[John C Cox]

Very cool. I would love to hear a recording.

How are the home made string pins working out? I saw that you made them out of nails. Are those hard enough so they don't bend ovet time? I was expecting you to use zither or autoharp pins..

[Rick Potter]

Wonderful job, and great record of the build. That is something I can only dream of doing.

How long did it take?

+1 on hearing it play.

Rick P

[Phillip J Allen]

John,

I too was worried initially about using nails for the tuning pins but everyone else was using them. In a museum in Bogota Colombia I saw a clavichord with tuning pins that were even thinner diameter than my 16 penny box nails.
I think the real thing to consider is that there really is relatively low tension on these pins. When I had problems with my over-wound strings breaking I performed the string tension calculations and came up with the following graphs. The tension should only range between 8-3kg.

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So with only 2.7cm of a 16 penny nail sticking up from the sound board I wouldn't expect it to bend much.
But then time will be the final judge!

Phil

[John C Cox]

Very interesting. I was assuming you were using steel or brass strings... But that sort of tension would indicate gut or nylon... What are your strings?

[Phillip J Allen]

John,

The strings are yellow-brass wire and the lower 11 base notes are yellow-brass wire with Copper over-wounding wire. Clavichords & harpsichords both produce the best sound when the wire is "near" the breaking point. I think the maximum tension for some of the heavier gauge yellow-brass wire is close to 10-11kg, but I am not 100% sure. I am still learning.

Phil