Magnano 2003 10th September
SUPPLEMENT rev.42004715AkihikoYamanobe
Partlycorrectedin5concerningannealingtangentsfromtheoriginalinMagnano.
TothinkonclavichordinJapan,Itendtothinkonthebasisofphysicsoraonaphysical
approachbecausewehavealmostnooriginalclavichordinJapan.IwouldliketoexplainwhatIdidondesigningaclavichordinthefollowingorder.
1Generalstructure
2Considerationonacorner
3Consideringkeydesign
4Balancewasher
5Low-temparatureannealing(normalizing)tangents6Onjapaned/chinoiserieinstrument

fig.1GeneralStructure
upperpartofhitchpinrail(hardwood)rearliner
wrestplank

hitchpinrail(treble)
bellyrail
balancerail

toolboxrearwall
fig.1ahitchpinrail(Hubert'sdesign)

fig.1bhitchpinrail(mydesign)1GeneralstructureMostmakerswanttomakeclavichordaslightaspossible.Iamanother.Onthispurposeitisnecessarytothinkhowthestrengthcausedbystringsisappliedtoainstrument.fig1showeseachstrengthbyarrows.Thehitchpinrails(bassandtreble)wrestplankconsistofupperpart(hardwood)andlowerpart(softwood).Imaketheupperpartofbasshitchpinrail
8mmthick.Butiftheupperpartoftreblehitchpinrailisalso8mmthick,itdoesnotget
contactwithbellyrail.Evenifweuseverystronggluebetweenlowerandupperpartof
hitchpinrail,itdoesnotmakeuporcompensatethis.
Pleasefindthattheupperpartofthetreblehitchpinrailinfig1.Itgetsthickertoward
thetreble.Inthismannertheupperpartofhitchpinrailcangetacontactwithbellyrail.
fig.2Generalplanview
hitchpinrail(bass)

wrestplank

hitchpinrail(treble)

rib

hitchpin

bottombellyrail
graindirectionbracetoolbox

balancerail

toolboxrearwall

Drawnassoundboardtransparent.

fig2showstopview.Pleasefindthetoolboxrearwall.Thebasshitchpinrailwantto
movetotheright.Therearwallbringsthisforcetothebalancerail.Thereisanotherpass
behindtherearwall.Thebalancerailitsselfhasacontactwithlowerpartofthebasshitchpinrail.Soonthisparttherearetwopassesfortheforcewhichisshownbytwoarrowsonthefig2.Thevibrationofbasshitchpinrailgoesintotwowaysattheleftsideofthetool
boxrearwallandcomestogetherattherightsideofthetoolboxrearwall.Thesetwo
vibrationswhentheymeetagain,arenotequalbecasetheyaretransformedbymaterialsand
attheglueingphase.Itisnotgoodbasically.Perhapsisdesirableorrationalforforceresistantstructure.Thisstructuremaycauseslightlypeculiarorcolouredsound.2ConsiderationonthecornersSharpedgedcorneronthecaseoftheinstrument,keysoranypartshouldbeavoided.
Theviolinorcellodoesnothavesharpcorners.Allthecornersareround.
So,Imadealmostallthecornersofthecase,hitchpinrails,balancerail,soundboardbars,thecutoffbarandkeysroundsothatIdonotremainsharpedgessofarasIcan.Followingisa
considerationonthevibrationofthepart.

fig.3Actofthecornersedge
Thethinlinesshowlongitudinalwaves.Thethicklineshowsacrosssectionofthepart,forexampleakey,soundboardlib,caseandsoon.
Thevibrationofthepart,forexampleakey,makewavesintheairlikethis.Atthe
surfaceofthepart,therecomebackthereflectedwave.Itwilldisturbthenormal
vibrationofthepartifithasasharpedgedcorner.
3a.sharpedgedcorner

3b.roundcorner

Thesefiguresareexaggarated.Actualwavesshouldbemorecomplexed.

3ConsideringkeydesignItisobviousthatonclavichordsakeyismoreimportantthanharpsichordsbecausethekeyisnotatooltopushajackbutitsupportsthevibrationofthestringwithatangent.
Tomakethecornerofthekeyroundisonewaytoproducesanaturalsound.SoImakeall
thecornersround,andsandedbyafinefilesothatthereremainsnocoarselyorroughsurface.Whattheproblemisthekeytop.Nooneiswillingtoplayaclavichordwithoutkey
tops.Generallyspeakingkeytopsdisturbsnaturalsound.Someonemaynoticedthatafter
glueingkeytailthetonechangesquickly.Keytailmaybetheworstperhapsbecauseitis
gluedonakeyinalongareaortheremaybeanotherreason.Ifilethekeytailthininthe
back.Thisreducesthebadnessofthekeytailalittlebit.
fig.4keydesign
keytail

mortiseforabalancepin

keyheadAholeisnotdrilledthroughthekeybuttheholestopsbeforecommingouttheoppositeside.Thetangentsarecuttothelengththatthebottomofthetangentscomefirmlyintothekeythemselvesnotstoppingintheholes.
4BalancewashersIuseverygoodcowskinforbalancewashers.Theyshouldbesmallerthebetter.Theyare5.5mmindiameter.Veryweaknaturalgluehassoakedintotheminordertoeliminate
rustlingoftheskin.Idonotknowyetifthegluetreatmenttoskinwashersworksvery
goodornotsomuch.
5Low-temparatureannealing(normalizing)tangentsIboiledtangentsinoilinordertoeliminateremainingstressofthem.Thetangentsarecut
fromasheetofbrass.Sotheyshouldhavestressinthemselves.Andthisshoulddisturb
naturalvibrationsoftangents.IfeelthistreatmentimprovesthetonequalitysofarasI
tried.Butfromthepointofmetal-engineeringthereneedsfurthersurveyonwhatoccurs
inthemetal.

saladoiltangentscoilsofstringafryingpan

CautionSaladoilmaynotbegoodforbrassorothermetal!
Becausesaladoilmaygetthemrusty.Machineoilorbetteroilwillbeavailable.
CautioninadditionIboilednotonlytangentsbutalsostringsonce.Thetemperatureofthesaladoilwasgenerallylow,sotherewasnotlargediffererenceofstrengthofwiresolongasIevertried.Butitisnotgoodifthewireisannealedtoacertainlevel,becausebrass
wiregetstooweak.
6Onjapaned/chinoiserieinstrument
IthoughtthatthejapanedfinishwhichiscalledURUSHIattractive,butURUSHIisvery
hardwhenitisdried.Sothevibrationreflectsatthephasebetweenthewood-thefilmof
URUSHIandalsofilmofURUSHI-air.Thiswillcolourthesoundoftheinstrumentin
comparisonwithamorenaturalfinishedinstrument.Especiallyonclavichordsthiscolourmaynotbesosmallasonharpsichords.