Cembalobau Erfahrungen

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Text of Cembalobau Erfahrungen

  • Martin Skowroneck

    Harpsichord Construction Erfahrungen und Erkenntnisse aus der Werkstattpraxis

    A craftsman's workshop experience and insight

    Edition Bochinsky

  • Bibliografische Information Der Deutschen Bibliothek Die Deutsche Bibliothek verzeichnet diese Publikation in der Deutschen Nationalbibliografie; detaillierte bibliografische Daten sind im Internet iiber http://dnb.ddb.de abrufbar.

    Bibliographic information published by Die Deutsche Bibliothek Die Deutsche Bibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available in the Internet at http://dnb.ddb.de.

    0 2003 PPVMEDIEN GmbH, Edition Bochinsky Bergkirchen

    ISBN 3-932275-58-6 Fachbuchreihe Das Musikinstrument; Bd. 83

    Titelgestaltung: nawim96 Bilder: Martin Skowroneck ijbersetzung: Tilman Skowroneck Lektorat: Jan GroRbach und Nigel Edwards Satz und Layout: nawim96 Druckerei: Scherhaufer, Augsburg

    Alle Rechte vorbehalten. Nachdruck, auch auszugsweise, sowie Vervielfaltigungen jeglicher Art nur mit schriftlicher Genehmigung der PPVMEDIEN GmbH.

  • 153 PREFACE 211 Assembly 212 Final touch up

    155 CHAPTER I: TOOLS AND ACCESSORIES 213 Installation of the slides and guides 157 Planes 157 The cabinet scraper 215 CHAPTER IX: JACKS 158 Hand tools for mouldings 215 General considerations 158 Clamps 216 Preparing the blanks

    217 Slots for the tongues and dampers 161 CHAPTER 11: PERFECTION AND PRECISION 21 8 Drilling

    218 The tongues 164 CHAPTER 111: THE CONSTRUCTION 221 Assembly

    164 Preliminary thoughts 165 Scaling calculation 223 CHAPTER X: VOICING 168 Practical elaboration 224 Form

    226 Material 174 CHAPTER I v THE CASE 228 Delrin

    229 Working with Delrin 182 CHAPTER V: THE SOUNDBOARD 23 1 Difference

    182 Choice of material 183 Joining 233 CHAPTER XI: SECRETS AND TRICKS 184 Gluing 234 About gluing 185 Planing 237 The secrets of the soundboard 187 Bridges, ribs and 4' hitchpin rail 238 The thickness of the soundboard 191 Bridge pins and rose 240 Soundboard wood

    193 CHAPTER VI: KEYBOARDS 193 Frame 194 Key panel 195 Marking 196 Choosing the guides 197 Drilling 198 Keyplates for the naturals 199 Cutting the keys 199 Finishing 201 Adjustment, placing 204 Key plate materials

    206 CHAPTER VII: THE WRESTPLANK

    242 4' hitchpinrail 243 Sizing and varnishing the

    soundboard 245 A RUCKERS SECRET? 245 An Attempt to answer a yet

    open question

    250 CHAPTER XII: FINISHING

    260 CHAPTER XIII: HOW IT ALL BEGAN

    266 CHAPTER XIV: PROSPECT 266 Quality 267 Copy

    208 CHAPTER VIII: SLIDES AND GUIDES 210 Sawing off the slides 269 BIBLIOGRAPHY

  • his book is the result of all the innumerable questions asked by colleagues and amateurs during my entire professional life. Having started as an amateur myself, both amateurs and professionals always were welcome with me. So I would like

    to have the 18th-century term Fur Kenner und Liebhaber (for connoisseurs and amateurs) as a motto for this book. I certainly preferred informed questions: they often made me pay attention to details that had escaped my notice and contributed to many new insights or more elegant solutions. But even such questions, which entirely missed the core of a matter, could be inspiring. I learned to know, and if possible, to understand apparently inadequate ways of thought, before responding. As a late result of these efforts, this text might sometimes resemble a lecture, whereas in other places, technical descriptions and the explanation of working steps get into considerable detail to avoid misunderstandings.

    I always react openly to questions, without secrets. Even experiments in my workshop are kept private only until they are completed, to prevent the premature circulation of conclusions that may prove wrong at a later stage. It is like my profession as a music teacher: even here, there should be no secrets. A teacher can support his pupil by giving every possible information and individual help, but the music making will always remain the pupil's responsibility, and not the teacher's.

    Some of my statements may seem contradictory at first sight. The topic is too complex - generalized tenets do not lead to good results. If my ideas about details are detached from their context, the interaction of various decisions or working steps might not be fully understood and the isolated instruction may seem absurd. In certain passages, I address the reader directly. I found this the easiest way to describe the work and to discuss problems. For instance the chapter on voicing is based on a lecture, and I have kept its style unchanged since it fits the issue well.

    This book should be understood as a collection of materials and thoughts on various harpsichord-building issues, and not as a complete course. I doubt that such a course is possible. For full understanding, the reader should be familiar with the following standard works: Frank Hubbard Three Centuries of Harpsichord Making', Raymond Russell The harpsichord and Clavichordz and ideally also: Grant 0 . Brien Ruckers. A Harpsichord and Virginal Building Tradition3. Basic knowledge in music theory and acoustics is also helpful.

    As diverse as the individual opinions in our branch of instrument building are, as diverse seem to be the motives to make these public: here we meet organic curiosity, scholarly ambition, an urge to circulate recipes to 'improve' instruments, descriptions of working principles in advertisements but also plain commercial tactics or undisguised jalousie de me'tiel: Accordingly, the quality of verbal or written statements varies; the spectrum stretches from serious scholarship to questionable claims or even mystery making. One fundamental mistake seems to reoccur in some of these utterances disregarding their status. Often a detail is regarded as the single most important cause of the quality of a whole instrument. Therefore I want to introduce a second motto, which for a long time has helped me to keep my independent judgment intact: Don't Believe Him Who Knows

  • Exactly. A motto, which my readers should have in mind even when reading my book! I certainly try to find logical and stringent arguments for my descriptions, but yet I am one of many subjective voices. Therefore I prefer readers who arrive at different results, to those who extract indisputable rules from every half-sentence. Often, only my personal view makes this text different from known facts. In order to be complete, I have at times not avoided certain basic information, even though it might be known to most readers.

    The chapters of this book are based on each other, meaning that preceding information often explains the following statements. So if, for instance, a reader is tempted to jump immediately to the chapter "secrets and tricks" to find 'certain passages', he will have less pleasure and profit than otherwise.

    The terminology of this English translation is adapted from various lists as found in the book by Frank Hubbard, in dictionaries of terms in music and on various Internet lists. Generally, English harpsichord terminology is more descriptive and less misleading than the German Fachwortel; which at times are somewhat ridiculous or even misleading. The comparative discussion of various terms at this place in the German text can therefore be omitted.

    For their valuable help during the work on this book I wish to thank:

    - My wife Susanne, who during more than 4 decades has made my work easier. She transcribed my pencil scribblings into readable text.

    - Our son Tilman, who through his experience as a harpsichordist and in maintenance of different conservatory harpsichords gave me valuable advice. He made the graphs to the present book and made the pre-editing of both versions.

    I also wish to thank everyone who gave me inspiration or asked questions, and my open- minded colleagues.

    1 Hubbard, Frank 1965. Three Centuries of Harpsichord Making (Cambridge, Ma.: Harvard University Press. 2 Russell, Raymond 1959. The Harpsichord and Clavichord (London: Faber). 3 O'Brien, Grant 1990. Rnckers. A Harpsichord and Virginal Building Tradition (Cambridge: Cambridge University

    Press).

  • TOOLS AND ACCESSORIES 155

    TOOLS AND ACCESSORIES his chapter does not contain a complete description of the tools common for harp- sichord building, or their use. I also avoided admonitions about tool sharpening or their maintenance1, since I do not seriously expect my readers to spoil their

    work by scraping about with blunt tools. I simply want to tell about my personal experi- ence with my tools. This is basically an experience of someone, who once started as an enthusiastic amateur without any education in a craft (apart from a three-month course in bricklaying in 1945). This starting point possibly makes this chapter more interesting for the amateur than for the professional builder.

    For many years now, the do-it-yourself clientele seems to have surpassed the profession- al craftsmen as an economic factor. Formerly there were special stores that only delivered to craftsmen and firms (this had partly to do with the German tax system). Here one could buy or order tools, screws, nails and other small parts of a good quality. Today, we have to go to the do-it-yourself-store to which the old firm has been transformed, if it hadn't given up a long time ago. Here we encounter a seemingly endless choice of tools, parts, accessories and gadgets, which even the most playful fantasy cannot imagine. But the longer the time spent pushing our shopping cart around, the longer the faces. Small parts are packed by the dozen in plastic boxes for a price that once bought two hundred. Screws are only available in a few standard sizes, and already from the outside of the box we dis- cover a great number of blanks or damaged ones. Certain things seem to be altogether unavailable, like massive brass hinges, which used to be common in all the stores. When asking, one is sent with the impatient answer "here right in front of you" to the rolled brass hinges. I couldn't even find out whether the massive hinges still are produced.

    The choice of tools and power tools is enormous, but their quality and usefulness varies enormously too. Unfortunately, the quality of power tools is dominated by DIY stan- dards. For instance, I have been using a little Bosch power drill of only 60 watt for more than 40 years. It still works very precisely without any loose play. At the time of pur- chase, this machine was certainly not expensive. Now why do all new power drills have so much loose play right from the start, so that the resulting vibrations only worsen the problem? Why are all these machines laid out for 400 watt or more, whereas the de- scription - and the chuck - do not allow for drills much bigger than I used in 1953 - with 60 watt? Apart from a burned-out capacitor I had not a single problem with my old ma- chine. When I later needed a second drill, it soon had to be replaced by a third one, after several costly repairs.

    Even the usual range of hand tools seems fragmentary. For instance, I have been search- ing a half dozen stores for files to sharpen the blades of my circular saw - in vain, even though they all carried blades of all possible sizes. The only thing I could get were com- mon triangular files. Apparently the reason for t h s is to encourage a behaviour, which is diametrically opposed to the traditional conception of dealing with hand tools: formerly, a craftsman cared for his tools in such a manner, that they gradually adjusted to his spe- cific working technique. Therefore we have the subjective impression (or is it objective?) that a worked-in chisel performs better than a new one. The overly complete supply of blades and no files to sharpen them demonstrates what the customer - now consumer - is supposed to do: throw a blunt blade away and buy a new one.

  • But let's face and discuss the rich choice of hobby tools. As I love experiments, I have tested some, although very sceptical. Certain unpromising gadgets I didn't even try. Other tools, which I approached rather reluctantly, proved to be surprisingly effective, like the plastic handles for stick-on grinding or filing foils supplied by the Swedish firm Sandvik (unfortunately they were taken out of the assortment in spite of their usefulness), and some other grinding tools. Thus some typical hobby tools, used appropriately, proved to be a real enrichment. On the other hand, certain small planes fitted with throw-away blades or suited for razor blades do not work at all, or perhaps only on tool-fair demon- strations. Perhaps one can produce a handsome amount of wood shavings with these planes when breaking the edges of straight-grained soft wood, but already on trying to plane a surface of lOmm width the blade gets jammed and breaks. No wonder; the blade easily flexes out of the plane, so when it gets stuck, the problem only gets worse.

    Similarly I had no good experience with a set of rasp-like tools called Surform. Only the round rasp was useable. As a disclaimer, I should add, that I possibly did not understand the right way to handle them - well, after some experiments I did not care any more. Another tool I never managed to handle properly was a motorized handsaw. Of course, the work piece needs to be clamped tight, or the thing does not work at all, but even then, its rattling and shaking remains impressive - certainly not a tool to make the job significantly easier, unfortunately not even when cutting firewood. Combination tools are often problematic: for instance, the centre of gravity of the sander accessory for power drills is so inconvenient, that hand sanding remains the easier alter- native. High-speed mini drills and their accessories are useful, even though I would prefer a lowest speed well below the usual 15000 or 20000 ulmin. This is the only power tool which I dare to use for drilling bridge pin holes; its power is low enough to help detecting hard or faulty areas in the wood before the drill breaks.

    Another important recommendation for drills: take the expensive 'malcus' drills which are pressed or rolled in the form of the drill, and not those, which simply are milled out of a piece of round steel. Their inner structure is more stable which makes them more re- sistant to breakage. This is especially important for small diameters. A broken drill inside its hole is a hopeless thing, especially if there ought to be a bridge pin instead. Flat drill bits for larger diameters are cheap. But even here, the quality varies, and a more sophisticated drill should be preferred. But I would hesitate to use even the sharpest one free hand - only in a proper drill stand; then they perform unexpectedly well. These drills also are excellent starting points for making special drills for key fronts, or for custom made cutting or punching tools.

    Another useful, but expensive novelty should be mentioned: 'micro mesh' a sanding medium on a textile basis. I use it for sanding painted surfaces. The gradations stretch from fine sandpaper to extremely fine. Its coating prevents this material from getting clogged like common sandpaper, and there is a special rubber for cleaning.

    Japanese tools are still relatively new in Europe. The saws and planes - to be pulled rather than pushed - work very well, and like the chisels, they remain sharp much longer than usual. Their high quality is equalled by the price; also, as many special tools are offered for special jobs, one needs a large collection. Some of these special unknown cutting tools are very effective. It is well worth reading books on Japanese woodworking and enrich- ing the western toolbox with these tools.

  • Planes

    Some remarks on the hand plane, which in modern carpentries has largely been replaced by machines, seem appropriate. Many customary hand planes, from the tiny ones for vio- linrnakers to the largest ones, are to some degree faulty, which in its turn accounts for the decrease in popularity of this ancient and useful tool. A plane cuts properly only when op- timally designed and prepared. New planes scarcely are. The soles of most iron planes need to be sanded, or ground true, which involves a lot of work. A simple steel ruler, held straight on - and diagonally across - the sole, will reveal any hollowness, unevenness or twist of a "ready-for-use" plane. Also, many plane blades are ground coarsely and at too high tem- peratures. Careful honing does not help when the steel has thus been softened; only when, after long use and much grinding and honing, the steel becomes shorter, its edge gradually becomes more stable. Expensive planes present fewer problems of this kind, but unfortu- nately the price is no guarantee; still it is worthwhile to invest more money here.

    Of all wooden hand planes, the most expensive ones almost always have one principal fault: to make the sole resistant against wear, it is made in harder wood than the body. Usually the body is made from beechwood and the sole from hornbeam; a more expen- sive variant combines pear and lignum vitae. In both cases, the shrinkage of both species differs (even lengthwise, which is often neglected), making these planes hollow or con- vex according to the weather, but almost never straight. Apart from the trouble of straight- ening the sole before every use, this would not really correspond to the original aim to pre- vent wearing out. For this reason, I exclusively use metal planes, apart from my wooden moulding planes (see below). Once straightened, they function reliably for a long time. Sometimes, the manufacturers of planes no longer mention the specific use of a special plane design, which may cause a problem in practice. For instance a small low angle plane (with the bevel of the iron up instead of down) might be offered as "one-hand- plane", or even "trying plane", whereas the old German term "Vergatthobel" (vergatten = to join) tells more about its proper use: this plane was used to prepare the surfaces of large baroque mouldings before joining; its special design allows for cutting across the grain at various angles. Even if one can use this plane for some other tasks, truing a flat surface is not amongst these.

    I already mentioned Japanese planes. These have to be prepared in a special way before use. Their preparation is not easy and should not be done without a precise instruction (for instance, here the sole should not be true). Many suppliers carry special literature about this, which absolutely should be consulted; it is well worth while the effort. At first sight, so-called boat planes (with a bent sole) seem to be ideal for harpsichord builders. But in practice, their fixed radius only fits one shape, so one would need a whole collection of such planes to meet all needs. Those with a flexible sole seem a better choice, but unfortunately the sole remains flexible at work too, causing the iron alter- nately not to cut at all or to jam into the same workpiece, without even having changed the iron's position.

    The cabinet scraper

    In harpsichord building, cabinet scrapers are useful not only for finishing problematic wood surfaces, but also for fine work on bridges, wooden strips, in confined areas and

  • on action parts. It is worthwhile to get accustomed to sharpening and using this seem- ingly simple tool.

    Hand tools for mouldings

    I usually make my mouldings according to one of the two historical principles2. Mouldings are made either using special planes or they are scraped. During the fifties, I started collecting moulding planes. In the Kalverstraat in Amsterdam, a tool shop offered a remaining stock of new moulding planes for one guilder per piece. At the flea market at Waterlooplein, old moulding planes were offered literally in heaps around the same time. Unfortunately these times are past, and today one must be content with a few pieces sold for fantasy prices in antique shops. Nevertheless, I recommend their use. They per- form smoothly, and if one takes the direction of the grain into account, the results are neater than with a router.

    It is relatively easy to make one's own moulding planes. If a moulding of a certain shape was unavailable, or if I couldn't adjust an existing plane to a desired shape, I made a new plane. A piece of hardwood is prepared with the negative of the desired moulding. This can be done with a router, or by sawing with a circular saw, filing and sanding step by step. Some wooden special planes can be used as a starting point. In the same manner, the irons of special planes, like the ones used for grooves, can be used for profile planes. First, they need to be softened by heating. After applying the proper shape of the desired moulding, they must not be hardened too much, because they are sharpened with files. The groove for the plane iron can be made at a slight angle (seen from above) to help pulling the plane towards the workpiece. Otherwise one must press the plane against the workpiece since the direction of the grain chosen for good results pushes the plane outwards.

    A second technique is scraping, using a "scratch stock": a hardwood block is fitted ver- tically with an iron (a piece of a cabinet scraper, or a bit of a saw blade thick enough, filed to the appropriate shape), so that it protrudes just as far to match the amount of wood to be scraped off. There is no need to shape the block itself in any special way. This manner works surprisingly well even on parts with irregular grain, or on bent surfaces, like the bridges or the hitchpin rail. At the beginning, everything seems to lead towards a rough and uncontrolled disaster. But the deeper the scraping, the neater the moulding, until at last the block rests on the unmoulded surface, and only the last slight irregulari- ties are shaven off. This manner of making mouldings is very ancient. In the 16th centu- ry, one used huge benches similar to those used for wire making. The Strips or planks of wood were pulled through underneath a fixed iron. For the wavy mouldings, as used for picture frames, furniture or instruments, correspondingly wavy strips of wood were pulled through together with the new profile3.

    Clamps

    An old carpenter's saying goes "you cannot have too many clamps". This applies cer- tainly to the harpsichord builder, because tasks like gluing the sides to the inner con- struction, or the liner onto the sides, or making bent parts from multiple layers of wood requires more clamps than most carpenter's jobs. One needs not only many clamps, but

  • TOOLS AND ACCESSORIES 159

    clamps of all sizes and of various systems to add up to the necessary maximum number. Arriving at the quantity required is not too difficult; even heavy, long or wide clamps can be applied in many ways, if they are placed carefully and supported strategically. A use- ful light variety is the "Klemmsia" a combination of wooden parts and piece of steel band. As I recall, these cheap clamps were developed just after the war, when raw materials were scarce, but they proved to be fully useful and cheap and they are still available to- day. Their advantage is, apart from their easy use, a construction based on a few simple standard parts. Therefore, one can easily combine sizes not included in the standard pro- gram. So, years ago, I purchased some clamps made after my own wishes for the ordinary price. A few drawbacks of this construction are for instance that the hornbeam heads, de- pending on the grain, sometimes split up, when the handle is pulled tight. Also, the earli- er variant made using steel band sometimes slips, so the clamp loosens. Some ordinary clamps also have this problem. Galvanized clamps of a newer date normally don't slip. Of course, the total pressure of these "Klemmsia" clamps is lower than that of ordinary clamps. Also, clamps with a long stretch ought to be made from steel, even though they are clumsy and heavy. Two of my large wooden clamps (beech, with a screw handle of hornbeam) became disjointed after only being used twice - too expensive for firewood.

    A clamp-construction for larger surfaces, described in the chapter on soundboards, is omitted here. For several years now, spring clamps of a variety of sizes and designs are available, small ones to be opened with two fingers but also some, which require as much strength to open as the arch of Odysseus. Almost all sorts are cheap and useful, especially for gluing long and narrow or thin strips, like mouldings. Some spring clamps have cush- ions of soft plastic, which unfortunately tend to discolour resinous or aromatic species of wood. Some gluing jobs in harpsichord building, like attaching the hitchpin rail from the inside to the bentside, require special clamps. This is an important issue for the overall stability, much like the attachment of the hitchpin rail to the soundboard. A high hitchpin rail presents no problem, but one with a low profile, and possibly a moulding at the edge, is better attached by using a custom-made clamp.

    metal screw

    , .

    , . *.,.

    . a. ,,

    , , .. ,, .. ,.

    . . * ,. .. ,. .. ,. .. ,. .. ,, .. ,, 8 , ,#

    cork or leather .. ,. . . .. . . ,. . . ,. a . ,, .. ,, ,. ,.

    . a ., ,, ,, .. ,, ,. ,. . > ,,

    i .... < L,, . . , . . ...___.' .

    scale 1 :2

    This drawing shows one possible solution. It is no big task to make, say, twenty of these clamps, and then one has a useful aid for all harpsichords and early fortepianos. Any dif- ferences in bentside or hitchpin rail dimensions can be adjusted with small blocks of wood.

  • An important method of clamping is the use of wooden strips, called go bars, bent and tensed against a surface, such as a low ceiling. This allows for quick and precise clamp- ing. This method is traditional in piano building. I made my counterpart under the roof ridge on the attic. Depending on the weather, I can glue ribs and bridges under desired conditions: during the summer sometimes the temperature rises above 40" C and the hu- midity sinks below 20%. Choosing the right moment, I can control the humidity of the soundboard quite precisely.

    Other jigs and special tools are described in the respective chapters.

    1 I recommend Kingshott, Jim 1994. Sharpening (Sussex: Guild of Master Craftsman Publ.), a book that contains much useful information.

    2 Only once, I used a router to apply a moulding to the short sides of a clavichord bottom, across the grain. 3 This procedure is described in: Gerber, Josef M. 1956. Die Geschichte des Hobels von der Steinzeit bis zum

    Entstehen der Holzwerkzeugfabriken imjkihen 19. Jahrhundert (Ziirich: VSSM-Verlag).

  • ~ R F E C T I O N AND PRECISION 16 1

    PERFECTION AND PRECISION

    u sually, one of the four grooves that optically divide the fronts and back parts of the bone keyplates of Ruckers harpsichords is incomplete at some place (in con- trast to later practice, the division is in fact optical, since the Ruckers keyplates are made of one piece). This is a symbol of the modesty of the master; only God can make a thing perfect. This interrupted line is certainly just a symbol; a closer look at historical instruments makes clear, that the old masters hardly indulged in too strict a perfection. The Ruckers instruments reveal a, for our taste, remarkable degree of imperfection. Inside the instruments, we encounter rests of bark, rough tool traces, and especially, considerable differences in the dimensions of construction parts of comparable instruments. But in places of importance for the result, the work was done really carefully: the selection and preparation of soundboard wood, or the scaling - if it has not been changed later on - are of such quality, or precision, as in few other historical schools.

    These two terms need to be further investigated. First of all the quality of a soundboard: historical soundboards tell us that quality, precision or even 'flawlessness' were opposite extremes between which the master had to find the best position. Any superficial 'preci- sion' was regarded as less important than the quality, to be defined as the best possible suitability for the sound. The treble was fine-grained and the whole soundboard was made of quarter-sawn strips (anyone who makes his own soundboard instead of buying them ready-for-use at a special firm knows, that it costs an effort to meet these criteria: coarse-grained strips often are not long enough, or faulty, and isn't it a pity to cut the fine strips to bits for the treble?). Small knots, variations in the direction of the grain, and oth- er small faults were accepted if the overall quality was good. Bigger faults were accept- ed in the less 'dangerous' areas, like on the 4' hitchpin rail, or behind the cutoff bar. The painted flowers or animals could camouflage all these flaws. Also, the rose could be used for cutting out a faulty area, or even to join two shorter strips of wood lengthwise. A less surprising result of assembling a soundboard this way, is that the strips may vary in width in a rather haphazard way. But we scarcely encounter sudden changes from fine-grained to coarse-grained wood.

    The result of this painstaking selection has nothing to do with 'perfection' in the current sense. Today it is almost unimaginable that this effort was maintained in spite of the high production of the Ruckers workshops. When working with wood, the limit for precision is reached pretty soon. It will not be possible to work to tolerances of, say, 1/100mm, and even if one succeeds, one only needs to look once in the wrong direction to spoil the result with one's humid breath. So in practice, for instance a scaling may vary millimetres in the treble and centimetres in the bass.

    Action parts, of course, need to be made to closer tolerances to ensure a proper per- formance. But also here, sheer millimetre-faithfulness alone is no guarantee, not even a prerequisite for a reliable performance. On the contrary: if the jacks are made with too close tolerances (i.e. the jack in the register, the tongue in the jack, or on its axle) problems will ensue. To understand this, we only need to remember that during weather changes, the material will treat our carefully observed tolerances obstinately and undis- ciplined. Occasionally, one can experience the results of this in new jacks and registers

  • in museum instruments; such parts from restorations of the 20th century have contributed to the myth of the unreliability of the 'primitive' historical action. Around 1959, Friedrich Emst, once restorer of the Berlin collection, almost declaimed in his fatherly manner: "The old have achieved precision with imprecise means." This is a sentence of more content than initially apparent, and it is well worth declaiming.

    When working by hand, great precision is a tricky goal. Even though historical jacks were made using planing jigs, the results sometimes vary considerably. Even a jig does not prevent the jack from becoming too thin, if it is pulled towards the plane iron, because of the grain going in the wrong direction or being irregular, or because some wood shavings have found their way into the jig. Even when using a drill gauge, a drill of 0.7mm might change course once it has entered a piece of wood. If this happened in the jack and in the tongue, one either has to throw away a certain percentage, or one could "achieve preci- sion with imprecise means", which in this case means combining jacks and tongues that have similar inconsistencies, so that the faults level out. A moderate divergence of the axle only disturbs the function if the tongue jams in the jack. Thus assembling the jacks (mounting the tongues) requires a good deal of attention. Unfortunately drilling both jack and tongue in one turn does not work in practice, as the drill will not keep straight all the way through. Better is drilling jig with two steel bushings, one above the jack, and an- other one in the gap for the tongue. These problems would not occur with an axle of larg- er diameter, but this would result in a higher friction and also could cause problems of space at the groove for the bristle. Planing jacks by hand will scarcely ever result in jacks that are not slightly thicker at one end. The thicker end becomes the upper part of the jack; otherwise one would need to force the thicker end through the upper register to fit below, where the thinner part would rattle loosely in the upper register. Should the lower register slots still be too narrow, the jacks can easily be planed to fit, with no bristle and no tongue disturbing. So the result is a ta- pered jack. My instruments contain many such jacks, even though most of them are made from a stock of 2 kilometres of beechwood strips, which I had made especially about 30 years ago. So these strips are absolutely regular. But even original jacks that are made as described above (which can be assumed, if all the jacks of an instrument are tapered) have no other advantage than their easier use to level out inconsistencies. Their function, and that of straight jacks are exactly the same. I cannot agree with the various other philosophies about the meaning of tapered jacks. A simple calculation shows why: if a jack of 15 cm is, at its base, 'hmm thinner than on top (which is a rather exaggerated figure), the difference in thickness, presuming a key dip of lOmm, will be '11s of that half rnm, which is far less than we need to prevent the jack from jamming, caused by climatic fluctuation.

    Much more important than a precise mechanical standard is a good balance between various factors: the distance axle-plectrum, the length of the plectrum, its thickness and the springiness of plectrum and bristle. By observing these points one can make even quite imprecise jacks to work reliably under all circumstances. Another source of pos- sible imprecision is the punching of the slots for the plectra into the tongue. Even a well thought-out and sharp tool may change direction when punching an irregular piece of wood. The tolerance for the angle of the quill is small upwards, and zero downwards:

    - A plectrum pointing downwards ever so slightly will not slide off the string. - Plectra pointing upwards naturally slide off, but the disadvantages are too big: - the touch gets hard and inflexible, and at the same time tough and imprecise.

  • PERFECTION AND PRECISION 163

    Also the plectra will break more easily. This has two reasons: first, the plectrum will be forced to protrude under the string slightly more than in its rest position; second, the string will be 'caught' longer, so its gliding off will occur later and more suddenly, bending the plectrum more acutely (here an experiment helps more than lengthy explanations).

    So one should try to make the slots exactly horizontal (i.e. at a right angle to the tongue), and one needs to control the results in regular intervals. Also this work needs a lot of at- tention, and if possible, practical experience of voicing a harpsichord. Only after working with completed jacks in the instrument does one acquire a feeling for the possible toler- ances at various points.

    The preceding explanation shows that I do not plead for imprecision or sloppiness. The contrary is true: one should always work as precisely as possible, or even better: as pre- cisely as necessary. The jacks of late English harpsichords can serve as another good ex- ample. Perhaps they are big and heavy in appearance, but every detail is very well thought-out - so well, that they were suited for the division of labour in the big harpsi- chord workshops in 18th-century Britain. Any precision exceeding this standard might not be a drawback, but it does not improve the result, and it makes the production slow and expensive, also because of high investments for precision tools, jigs and machines. Is this the reason why wooden jacks are much more expensive than plastic jacks? Or do they include a special dreariness- or hardship-charge? Now and then, I time all the work- ing steps for making 200 jacks, counting off all the discarded parts (about 1% of the tongues break during the punching, for instance); I have never exceeded the average price for plastic jacks. My small investments in material and work time making jigs and drill gauges were amortized after some hundred jacks.

    Finally I want to mention another advantage of working by hand: flexibility. As an ex- ample, it is not at all problematic to make small amounts of jacks of various dimensions or shapes for restorations and the like. Also, any new experience can easily result in ac- tual change of the production. When I for instance noticed that the distance axle-plec- trum in historical 4' jacks was smaller than in the 8' registers (which is logical, as the plectrum is shorter as well) I could change my own design right away.

  • Preliminary thoughts

    A coustically, a harpsichord is very complex. Together with the varying character- istics and the unpredictability of our living building material wood, this realiza- tion may cloud one's view of the fact that technically, building harpsichords is not all that difficult. Initially apparently impossible tasks are easily divided into com- fortable working steps that can be carried out without the need of an exaggerated arsenal of tools or machines - provided that one knows how to use and to maintain one's tools. Today, one possible, and for a beginner perhaps practical starting point is the acquisi- tion of a kit. Even though this is slightly beside my topic, 1 will give here my thoughts on this matter. Both enthusiastic and frustrated hobby builders introduced the issue to me, by asking me questions after getting stuck in their work. My many answers on kit building in the course of time are worth a brief summary.

    I do not share any principal reservations against harpsichord kits. This does not say any- thing about my possible criticism on details, like faulty parts, poorly written instruction books or wrong promises. But I do not believe that a harpsichord from a larger workshop necessarily will be 'better' than a kit. If a kit is good, a good harpsichord can be the re- sult. Its builder does not even need to understand all he is doing, provided he has some craft skills (more, than many advertisements suggest).

    A kit needs to be designed and produced to be more or less foolproof, which definitely is not the same as primitive. On the contrary, this might even result in better-designed de- tails, to prevent mistakes during the assembly. Also, since the customer will be able to check the quality of every single part, the selection of all the materials needs to be toler- able at least. In contrast, in a complete harpsichord, hidden material faults, bad joints or cheap solutions like the use of staples might well be hidden in the closed case. Not every builder resists this temptation. But unfortunately, not all the kits meet the requirements listed above.

    As an alternative for building a kit one could take a historical instrument as a model. Today, museums or special dealers offer a large variety of original plans, so it is possi- ble to 'copy' an original without the need of measuring it, even without ever having heard it. Even if the act of copying a historical harpsichord seems to be far more professional than the assembly of a prefabricated kit, it is no guarantee, that the builder understands what he is doing; the principal difference between both approaches is rather little in this respect.

    In the following example, a small Italian harpsichord with a compass of four octaves (C- c"') will be used as an example for demonstrating the development of an individual sketch. The goal is an instrument after a historical model (rather than a copy of one in- dividual instrument) made fit to meet specific requirements or circumstances, such as the intended pitch and the properties of the available strings. I will also explain some im- portant physical principles. Purposely, I will not refer to historical measuring systems, or to certain simple proportional relationships in the case construction. The most important basis is the relationship between pitch and string length.

  • Scaling calculation

    The scaling of stringed instruments means the length of the strings. In a finished instru- ment, it is fixed. Most bowed or plucked instruments (except theorbos or chitarrones) have strings of only one length. Their scaling is thus expressed with one figure (between nut and bridge). The scaling of pianos, harps, dulcimers, psalteries and related instruments varies from tone to tone and thus becomes subject to calculations. All explanations, which, apart from length and pitch, also combine the term tension (in kilogram) with the scaling, are wrong. Often this is an effort to find a neater basis for an inconsistent scaling, whether dictated by modem construction principles or simply miscalculated.

    The Pythagorean definition says that halving the sounding length of a string results in a sound an octave higher, doubling makes the sound an octave lower. A scaling based on this principle is called Pythagorean. This will be the basis for the following explanation. This is the simplest way to calculate a scaling: the string length of the string material of one's choice needs to have sufficient, but not too large a distance to the breaking point of the string at a given pitch. If the whole stringing is adequately and consistently laid out, this one empirical figure can help to deduce the whole scaling. First of all, all the oc- taves are laid out. Historical builders often marked c and f# (in the middle between the c's) with dividers. With a calculator, we can be more precise. The factor that will give us the 12 half tone steps (equally tempered) is ' ~ 4 2 . Of course logarithmic paper can be used instead of a calculator (albeit less precisely): to the left, on the regular scale, one enters the pitches, and on the scale on top and below, the octaves, which are easy to double or halve. All the dots add up to a straight line, from which one conveniently reads all the semitones. A consistent scaling might result in a harpsichord, which in the bass gets so long, that its static no longer is determined by matching the string load, but by counteracting sag caused by its own weight. Such a harpsichord has actually been built; it was designed after the calculations of a mathematician, and built in 1756 by Johannes Broman in Stockholm where one can still see and hear it. Even though its length of 3.60m and its eight legs make an impression as if something went wrong, its sound is amazingly sim- ilar to the historical 'average'. But for my taste the usual harpsichords of that time do not only look better.

    The string material for harpsichords until the end of the 16th century would have been either brass or iron (gold or silver are exceptions, which also can be alloyed and processed in a way to have breaking points similar to brass). This results in practice (tak- ing a = 440 Hz. as a basis) in a scaling that, with a reasonable safety margin, starts at f" with lOcm, f ' 20cm and so on. I do not take c" as a start, as usually done, because 10cm is so easy to handle. c" would have a scaling of 267mm. Any scaling that varies significantly from these figures indicates another pitch, or another string material, or a combination of both. In terms of pitch, the typical brass scaling and the (soft) steel scaling differ about a fourth. So for steel, c" can be lengthened to 350mm, but in practice, it is often somewhat shorter (also related to a = 440 Hz.). I have even tried really soft iron, like the soft wire for gardening purposes. It sounds dull and cannot be used for musical instruments. Also, its breaking point seems to lie even below that of brass. A good definition of the transi- tion from "white" to "yellow" strings, and from "yellow" to "red" (i.e. from steel via brass to red brass) can be found in Grant O'Brien's book on The Ruckersl.

  • For our Italian harpsichord we now choose brass strings, and the scaling for its four octaves (C - c"') is laid out. Taking the 10cm as a starting point, we get the following scaling:

    The figures of the great octave are in brackets, since in practice the scaling of the lowest notes is shortened to avoid constructions like the mentioned Broman harpsichord. In prac- tice, the bridge is bent, or joined at an angle in the low bass. It would at least be unusual - and not too functional - to make a harpsichord with a brass scaling (such as I will call our lOcm scaling) and a compass down to C, of a total length of 2.40m. If we analyse as many historical scalings as possible, we find various divergences from the Pythagorean scaling.

    This is the right moment for a recommendation: try to measure as many harpsichords as possible (in as much the curators of the collections will allow you). Make a collection of data, including the plucking points. I am convinced that only on the basis of many data, you will be able to work freely and independently. Only in this way, one gets to know about the 'average', and learns to understand the general setting and the limits, especially in terms of influence on the sound. So, when I started to build at the beginning of the fifties, I even measured all modern harpsichords, not to imitate them, but rather to under- stand why they sounded like they sounded.

    Back to our Italian scaling: in the bass area of original harpsichords, we can sometimes observe small deviations from the Pythagorean scaling; sometimes shorter and only rarely longer. A longer scaling should be regarded critically: in my view, bass strings longer than the doubled octave almost always came about through imprecise work, mis- takes during a restoration or similar influences. A shorter scaling, on the other hand, even

  • has several advantages. First of all, one creates a safety margin for avoiding the first mis- take (the longer scaling), which easily happens: in the bass, the angle between the strings and the bridge is very acute, so a lateral error of a few millimetres results in a difference of centimetres in the scaling. So, if we work using the actual figures from a certain his- torical instrument, instead of applying the underlying principle, and if we then accept similar inconsistencies as the old builder possibly did, the resulting faults could well be too big to be tolerable. This danger is even bigger as identical technical challenges then and now, like for instance the problem of precisely bending wooden parts, easily result in related faults, which then add up.

    Another reason to shorten the bass scaling is the tradition of using thicker strings in the bass, even though a precise scaling does not require this. This is done for reasons of sound. You should experiment when stringing your instrument. Of course, theoretically and with regards to the breaking point, the thickness of a string is unimportant; the diameter of a thicker string should match its higher tension. But in practice (as already described in historical sources) thinner strings are less prone to breaking, because the pulling of the wire causes an inner lengthwise structure, which makes it tougher, though strangely enough also more flexible2. I will later give some practical in- structions for a moderate foreshortening of the bass scaling in Italian harpsichords (not in all Italian harpsichords!).

    A different scaling principle applies to the northern European harpsichords from the 17th century onwards. The starting point - the doubling of the octave - is the same, but the Flemish Harpsichord makers, certainly the Ruckers family, made use of the progress in steel wire production (not to be confused with modern steel wire). Now, the scaling of f' could be lengthened from lOcm to 13 cm or 14cm. A consistent scaling on this base would result in a length of 2.80m for C and more than 4m for contra F. Apart from being un- practical, such dimensions are musically really unsatisfying and correspondingly useless. Such giants would be the opposite of certain modern compact-harpsichords with a single 8' register, and just worth as much, only without the advantage of a small box. Instead, the bridge of northern European harpsichords becomes almost straight in the bass, so their scaling deviates increasingly from the Pythagorean curve. This decrease is strong enough to make the bass of many of these instruments shorter than Italian harpsichords, in spite of the shorter scaling of the latter. As a compensation, in northern European harpsichords the strings get thicker towards the bass, and the material changes from 'white' via 'yellow' to 'red' wire (see above. I will later come back to the string material in more detail).

    My assumption that a correct steel scaling produces a poor sound was confirmed in an ex- periment. Of course I could not make a harpsichord of four or five meters length, but from a separate wrestplank, I could pull a string on to an existing harpsichord, across the room. The resulting chirping of overtones with no perceivable fundamental was charming, but practically useless. So the bass foreshortening is a musical as well as a practical decision. Foreshortening usually starts somewhere in the middle of the instrument, in the small or the one-line octave. There are several methods, some simple, some complicated, which re- sults in certain esoteric approaches to the matter, The simplest way is a foreshortening by optical judgment: the curve of the bridge is straightened to some degree, which corre- sponds with a shorter scaling. Some historical harpsichords have a straight bridge in the bass. It is rather unlikely that the principle behind the resulting linear scaling consists in exact calculations or deep thought. If we want to calculate the foreshortening, we could

  • gradually diminish the octave ratio from 1 :2 via 1 : 1.9 to 1 : 1.8 and so on (the half tone factor changes accordingly to 12d1 9 and so on). The result will not be too different from the first method. Another, more modem method reduces the whole scaling by using a smaller octave ratio right from the treble downwards3. The last method subtracts a fixed figure from each doubled octave. I have not found any convincing example of this prin- ciple; also, by mixing arithmetic and geometric series, this faulty calculation causes an increase of the octave ratio in the bass.

    One can keep speculating about the calculations and the secrets of the Old; the options may be number symbolism or the golden section. One should not forget, that their use of dividers and a few measuring points per octave resulted in a certain lack of precision. Feel free to calculate a little along these lines; it is amazing, how much can be 'proved' in this way. I am convinced, that the influence of such considerations on the quality of an instrument consists in nothing else than a more conscious approach and a more de- tailed working attitude, which sharpens in its turn one's view of other important details. Other observed deviations from the scaling seem to me the result of certain technical problems, or of the wish, to keep the bridge somewhat straighter than the calculation suggests. So for instance too short strings in the upper treble are rather common, as well as too long strings around the middle of the two-line octave. This can be observed more frequently in instruments with a narrow bridge curve, or where the bridge is actually made of bent wood. It is up to anyone to decide, whether this phenomenon has other hid- den reasons as well.

    I will present one last modern method, which according to my explanations above can be identified as arbitrary. Here the curve of the bridge is made according to optical and per- haps production-inherent aspects: for instance part of a circle is combined with a straight line. The result is scarcely calculable and largely coincidental. Modern string wire allows for almost doubling the 10cm scaling; the breaking point requires no attention. One can for instance find a description of this principle - or better its application without any ex- planation - in an instruction for the hobby builder to make a 'modem' harpsichord by Gerhard Krame?.

    This modern manner of making a scaling brings about that the necessary calculations come to deal with the string tension. In this way inconsistencies of the string length can be compensated by adjusting the string diameter, as described by Kramer, based on Hanns Neupert5. This principle makes no sense: first of all, the treble strings become thicker than the lower ones, which never occurs in historical instruments. Second, the constant string tension (Kriimer names 6.5kg6) is not historical either, as can easily be de- duced from old scalings and gauge numbers. Third, even though an equal tension seems to be a neat calculation, the sounding result is inconsistent and unsatisfying. Fourth, even though the tension is equal, the relative distance to the breaking point is arbitrary and varies enormously, which has influence on the tone and on tuning stability7. For an in- troduction to the various principles of scaling calculation this may be sufficient.

    Practical elaboration

    Now you need a big sheet of paper (at least 80cm x 240cm). For the sketch of the plan, we now need to determine the distance between the tones, i.e. between the strings, or

  • expressed otherwise, the slots in the registers. For this one usually takes a division gauge. To avoid this detour, I make my register guides before anything else, so I can take all the necessary measurements directly from them. This solves also the technical difficulty of making the guides really precise, regarding the distance of the slots. To be sure, all the guides have to correspond to each other, and the distribution of the slots needs to be con- sistent, but whether the guides are overall 5mm longer or shorter does not make a big difference. To start making the guides before everything else is a matter of convenience. The 'extra' guides (see the description in the chapter on register guides) can be used to put down all required measurements; even the distance between the 8' strings can di- rectly be taken over from the width of the slots (if they are not much wider than 3mm). The same extra guide is used to mark the location of the pins on the nut and the bridge. This method leads to great precision and to the correspondence of elements that need to match, in an area where a good deal of exactitude is needed. Yet one can work freely without a detailed drawing.

    Now you need to decide how much wider the wrestplank will be at the left (bass) side. In most Italian, early English and many German harpsichords the guides do not run par- allel to the keyboard, but lie farther away in the bass. This saves space, allows for a more elegant shape (with a shorter cheekpiece), and on close observation one also gains an ad- vantage regarding the balance point, even though historical builders do not seem to have observed or even made use of this (see my chapter on keyboards). This difference be- tween bass and treble is usually between 3cm and 5cm. I perhaps should say, it ranges from zero to an average of 5 cm and a maximum of lOcm (Christofori). For a convenient start, I recommend (for four octaves) an average figure of somewhat less than 4cm.

    Draw a long line parallel to the left side of the sheet of paper (i.e. left seen from the key- board). This line marks the inner side of the spine8. Now another line is needed, at right angles to the first one, plus a thin auxiliary line to mark the position of the register guides. Depending on the octave span (see chapter "keyboards"), a keyboard of four octaves will be between c. 65 and 68cm wide. Now add on each side 35mm space for the inner con- struction, the stop levers and for the distance of the last string respectively to the spine and the cheek. This may seem little, but when working precisely, there is no need for more. If you want to be careful, take four cm instead. More is not advisable (for a small Italian harpsichord). To some, it might seem practical or tempting to make space for writ- ing utensils and a cup of coffee on both sides of the keyboard, but the harpsichord will become too wide and bulky. Also I am convinced that any superfluous built-in space has negative consequences on the sound, because the treble - difficult for achieving nice- sounding results - actually would need much less resonating volume9.

    So you add seven or at most eight centimetres to the width of the keyboard. This distance is marked on the auxiliary line, from where you draw a diagonal line so that its distance to the keyboard is 4cm more at the left (bass) side, as mentioned above (there is no need to be overly exact. Only the definite line is mandatory). This line represents the plucking points of the longer choir of strings. Counted from the left, i.e. the line of the spine, a dis- tance of 35mm is marked, to find the position of the lowest string. Since we base our cal- culations on the breaking point, we must naturally take the longer strings as a point of departure. Now starting from here, all the longer (left) strings are marked along the plucking point line, by using a register guide, or another form of gauge. You can write the names of the tones right beside the marks.

  • For the highest note, we need to mark the shorter string as well, to be able to put down the inner line of the cheekpiece by adding 35mm. This line can be made parallel to the spine, or perhaps a few rnillimetres wider at the front (it is not infrequent in historical harpsichords to have a keyboard space which is a little wider at the front). Apart from making the building-in and removal of the keyboard easier, this looks better: exactly par- allel sides seem to converge towards the front. The typical later deformation through the string load further intensifies this effect. So now, we have marked the string positions along the plucking-line; next, the strings are drawn parallel to the spine, at both sides sticking out a little longer than their sounding length would be.

    Now you have to decide how far away from the plucking point you want to place the nut; in other words, how far towards the middle you want to pluck the strings. This is not an easy decision, and we want to give it some attention. As you perhaps know, the further a string is plucked towards its middle, the 'darker' (the more fundamental) it sounds. Exactly in the middle even the octave as an overtone is eliminated. Naturally, the string will have its greatest amplitude where it has been plucked, and will be less prone to form- ing a node at that point. The node of the octave lies exactly at the middle of the string.

    But this is only a rule of thumb, which leaves the rest of the sounding system unconsid- ered. How fundamental a harpsichord will sound is a matter of a balance of all the factors, which contribute to the sound character. The plucking point is one of these factors, but cer- tainly not the most important one. A harpsichord (or a certain harpsichord model) that tends to sound bright and rich in overtones cannot be converted to 'dark' by a different plucking point. This attempt is rather frequently made and the results seem pleasant at first, but they become soon tiring and gradually less satisfying. This makes me think of certain wines where the first mouthful tastes better than the second, and a second glass seems undrinkable. To make a good decision here is a matter of experience and a lot of observation. The collection of scalings, which I recommended, can be a great help here. A useful distance between nut and plucking point for an Italian harpsichord, meaning the distant 8' register at c"', can be between 40 and 60mm. This is doubled at c'. These marks are joined by a straight line, which is extended to the bass. From this line the string lengths are measured and put down on the parallel lines that represent the strings. Before deciding where to shorten the bass bridge you need to attend to another matter: The bass strings of the last 1% or two octaves need to be placed slightly to the right at the tail of the instrument, to allow for more free space between the last tone and the spine,

  • than the front distance of 35mm. One possibility would be to let all strings run diago- nally. But the need for more space in the upper half of the instrument and the reduced distance at the treble (compared to the original 35mm) are drawbacks of this method. If you instead start to place the strings from around the little octave and downwards, a little to the right, you achieve a slight ever-increasing bass foreshortening at the same time. If you find this effect too strong for an Italian scaling, you need to reposition the bridge as well.

    Also the following modification causes bass foreshortening: the nut of many Italian harp- sichords is (unlike northern European ones, which are straight or slightly bent towards the sounding string) bent towards the player. If you regard the (thin) line of the nut, you will notice, that it comes very near to the front at the bass. Now one can (after putting down the scaling) correct the nut line towards the left with a curve or an angle so that the plucking distance increases slightly less in the bass.

    All these methods result in a meaningful and slight decrease of the scaling in the bass re- gion, even all put together give good results. Here it is not too important to calculate the foreshortening exactly. If the bridge curve and the string distances make a harmonious impression, the decrease will be harmonious as well. A slight foreshortening in the bass

  • 172 CHAPTER 111

    has some advantages, but there is no absolute necessity for such a step, and no historical reason. In the majority of Old Italian harpsichords, the Pythagorean scaling is realized until the joint of the bass bridge. It is your decision if, and how much you want to devi- ate from this. The less foreshortening, the brighter and richer in overtones the harpsi- chord will sound in the bass, which means that the bass will also be less prominent. It is a matter of taste, and if you do not exaggerate in one of the directions (which also does not look harmonious), your results will be good.

    Now to the angle of the bass bridge: it is especially appropriate, if a short or a broken oc- tave is planned as well. Clearly, such an arrangement, where lower tones are transposed upwards, is not easily made in an area with a progressive scaling (even if in Flemish muselaers this is exactly the case).

    Now the whole area, which is covered by sounding strings, is marked out, and only the remaining surfaces need to be added. At the side of the nut, which is nearest to the front (that is in the bass), 4 or at most 5 cm are added to the front. Here a line exactly perpen- dicular to the left side is drawn, which marks the front edge of the wrestplank. Now the distance between bridge and bentside is needed, which determines the curve of the bentside. This distance is in old harpsichords between 8 and 15 cm. I have collected some thoughts about this in the chapter "Secrets and tricks" when discussing soundboards. Here I simply recommend starting with a distance of lOcm, to increase it in the bass to 11-12cm, and to reduce the treble corner somewhat. The latter can be done without harm; one saves space, and in the treble the bentside can be bent less sharply (you may recall that my call for saving space has nothing to do with the small modern apartments).

    Now you have everything: the outline of the whole instrument, defined by the inner line of the sides, the curves of the bridge and the nut, the string positions and the plucking points. The intended width of the register slides leads to the far edge of the wrestplank and the bellyrail. On the soundboard side, a line parallel to the plucking line is drawn in '12 register width, and on the wrestplank side ll/z widths of the register are added. This defines the width and position of the gap between the bellyrail front edge and the wrest- plank back edge. Now you only need to decide, how long the visible part of the keyboard shall be. To this, the nameboard thickness and a few millimetres plus the strip in front of the keyboard are added (if this strip will be located between the sides and not in front). With this front line, the shape (of the inner sides) of the whole instrument is ready.

    Many old harpsichord makers made these marks on the bottom board, and started build- ing directly, without a separate drawing. You can note down or simply remember the height between the bottom and the soundboard- and the wrestplank upper edges, and of the entire sides. As long as no one else has to work according to your plan, a drawing is superfluous. The same applies to the inner construction. There is no real difference be- tween choosing the position of the 'knees' and other parts beforehand when making a drawing, and directly building them in, except that placing and building gives a better impression of how the elements have to be distributed than on a sheet of paper.

    I do not need to describe the construction of northern European harpsichords; the differ- ent scaling has already been discussed, and other deviations regarding wall thickness, height and inner construction also need no special drawing. If, for some important rea- sons, one chooses to make a drawing, this can be done without problems.

  • O'Brien Ruckers. For more information on wire, and on this effect, see: Goodway, Martha and Jay Scott Ode11 1987 "The Metallurgy of 17th and 18th century Music Wire", The Historical Harpsichord 2, ed. Howard Schott (Stuyvesand N Y Pendragon Press). This method was used for instance in many fortepianos from around 1800. K r i e r , Gerhard 1979. Cembalo und Spinett - selbst gebaut (Merseburger:Kassel) Ibid. p. 81, table I. Ibid. p. 48. My observations suggest, that influences on the sound are primarily dictated by the distance to the breaking point. So, in contrast to many colleagues, I am less interested in the exact tension. Information about this can be found in various articles by Klaus Fenner (for instance ,,Bestimrnung der Saitenspannung des Pianos", Das Musikinstrument 11, 1966). I find it useful to mark only the inner lines, and to build everything else without exactly planned measurements. What does it help to draw two or three parallel lines for marking the thickness of the sides, the upper mouldings and perhaps also the lower moulding? Then one could also add a line to indicate the thickness of the liner. For documenting a historical instrument (during a restoration for instance), all this should be carefully taken down, but if you want to build a harpsichord, it is yon who makes the decisions about wall thickness etc. I do not see any necessity to include all these measurements in the drawing. You will certainly be able to recall a decision until you can cany it out; or else it is better to decide just when one wants to start building. Comparing the sound of a violin with what the cellists (and the composers) try to extract from the upper range of their instrument will clarify what I mean here.

  • THE CASE

    tipping

    s in the previous chapter, I will start by describing the Italian model. Since its walls are thin and the case is light, the wrestplank needs to be attached to a spe-

    . cial construction: the load of the strings tends to force the wrestplank in a rotary movement out of its position. The thin walls alone would not give enough sta-

    bility to resist to this movement. So the wrestplank is instead mounted on two planks at both sides that extend to the bottom and are attached there. These wrest plank blocks should be at least 15 mm (occasionally up to 30mm) thick. The treble block is best made to extend to the treble corner, where the bentside begins. Of course it is easier to make the left block of the same size as well. The blocks of some instruments only extend to the bellyrail; this construction is too weak and cannot be recommended. Sometimes the blocks were not cut level with the front edge of the wrestplank, but only cut out on the top; the lower part extends to the front edge of the bottom. This has the advantage of giv- ing the whole construction more stability. If the plank is not too thick, one can let it slope in decorative ornaments from beside the keyboard down to the front. This can either, to- gether with the outer wall, give a decorative ending, or - in a "false inner-outer" con- struction - it can imitate an instrument in its outer case. Such decorated planks occur also in German instruments.

    Flemish or French harpsichords have as a rule no wrest plank blocks, or only a very thin wooden strip. Here the wrestplank is let into the outer walls, which are rather thick. All instructions for building Flemish or French harpsichords I know proceed from the out- side inwards. First of all the sides, the wrestplank, the lower bellyrail, the lower frames (that is all parts that are let into the walls) are all joined. The liner, the upper bellyrail and the upper braces are only mounted afterwards. In most old harpsichords, work traces, and the manner of joining the parts suggest, that this indeed was the usual procedure. Italian harpsichords (and often German ones as well, which have many similarities with the Italian) are built from the inside outwards.

    First the bottom planks are joined together, planed, and the front bottom is glued in place. This cross-grain plank, which forms the front edge of the bottom, must be cut flush with the entire left edge of the bottom, and joined at right angles to this edge. Usually, a tongue is made at the front edge of the bottom to fit into a groove of the front bottom (the bottom parts of Ruckers harpsichords are scarf-joined instead). The right side of the joined bottom must not be cut to size; one leaves it slightly larger than necessary. Next the wrestplank is planed and cut to size, as well as the wrest plank blocks and the bellyrail. The wrest plank blocks are now very precisely let into the wrestplank, until about half of the wrestplank thickness (you also can use the full wrestplank thickness, but then it cannot be doweled as described below). When everything fits, the bellyrail is let into the wrestplank blocks (one can use a dovetail groove). When fitting perfectly, all these parts (wrestplank, two blocks, bellyrail - or if this is split: upper and lower bellyrail) are glued together to form a stable, frame-like part. One should not forget to start by soak- ing all end grain surfaces with glue. After drying, and after removing the clamps, one drills from above (through the wrestplank into the blocks) each three, and from the sides (through the blocks into the wrestplank), staggered to these, each four holes of 8-lOmm, and glues corresponding dowels in place. This results in a very secure attachment of the wrestplank. Also the bellyrail can be secured with dowels.

  • Now the drawing is laid out on the prepared bottom, so the front edge and the left edge, which are already cut to size, match their respective lines. Now the front edge of the wrestplank, the front edge of the bellyrail, the right side edge, the bentside and the tail are marked out on the bottom. Now you can glue the combined section of wrestplank and blocks precisely in its place on the bottom. Still, the bottom is not yet cut to size along the right edge.

    Now an end block is glued into the left tail comer. The direction of its grain should be the same as that of the bottom. This block needs to be 6-8cm long, as thick as the liner and, together with the liner, as high as the wrestplank blocks and the bellyrail. The same measurement is needed for the steps in the knees that support the sides and the liner. All the needed knees are now prepared. For static reasons these should be longer than high. Around the middle of the slant one makes a step at right angles to accommodate the clamps later on. Now you can distribute the knees on the bottom, and shift them about until you have a feeling of a certain balance. You will appreciate the advantage of this method over working with the fixed measurements of a drawing. The bentside needs more knees, to counteract string pull, than the spine. All the knees have to be placed at right angles to the tangent of the curve. The apparently logical idea of placing the knees at an angle to meet the string pull in the right direction is a mistake, which already Vito Trasuntino made in 1606l. Knees at angles cannot keep the bentside straight, as, under the string load, they tend to bend inwards together with it. Now you mark down the def- inite places of the knees and glue them in, one by one, the left ones precisely on the edge, and the right ones along their line. The next part to follow is the bass liner. At the front, it is let precisely into the left wrest plank block. But before doing this, you need to clamp a stiff, straight plank on its edge lengthwise under the left bottom edge. Otherwise the bottom would sag, and since the gluing-in of the left liner already results in a rather sta- ble construction, such a deformation would otherwise be permanently fixed. The bass end of the left liner is left a little longer; it will be cut off at a later stage, when every- thing is fixed (the assembly of parts that fit everywhere at once is an unnecessary incon- venience which perhaps only makes sense in kit building).

    Now you glue the bentside liner in place in the same way. Again - as later also with the short piece of the tail - you leave both ends a little longer to be cut to size when every- thing else has been assembled. It is not crucial how the bentside liner has been bent. I prefer bent massive liners, or those glued in three layers, to those with a lot of saw cuts. I actually draw the bentside on my plan after the prepared liner, after marking its exact position in relation to the bottom. Its curve needs to be rather precise for this operation. For bending, a negative parabolic form is the most useful (to be calculated similarly to the Pythagorean scaling), which should be longer than necessary. On this form, the liner can be bent or glued in three layers. If this curve is made long enough, it can be used in various types of instruments and scalings. A curve that in - or decreases regularly can be shifted to fit most circumstances. It also looks more elegant than a curve with a straight tail end (the latter indicates that the described method is not useful for copying historical instruments with a partly straight bentside).

    It is unimportant whether you glue a block (like in the left comer) or a knee into the right corner of the tail. The first pair of knees near the tail end is best combined to one U-shaped unit, which combines the opposite sides. The last piece is the liner of the tail. The rib- shaped bottom frames can be mounted following one's intuition, or after a historical model.

  • Any further decisions for reinforcing the construction are optional. For instance, some historical instruments have additional braces that run from the bentside diagonally to the bottom. I do prefer to be on the safe side with my constructions, to avoid the very an- noying situation where I don't dare to apply a heavier stringing, which might be neces- sary for the sound, for static reasons. Unhistorical for Italian harpsichords, but easy to apply and useful would also be some light braces to join the opposite sides of the liner, like they were used in northern European instruments. Like the upper framework of a boat is designed to prevent the sides to expand, and thus helps to keep the boat straight, the upper braces in the Ruckers instruments contribute significantly to their stability lengthwise. Here lies a major static weakness of the original Italian construction (and of certain German ones, like Zell or Mietke). For my own production, I decided to elimi- nate this static problem. I do not fear any drawbacks in the sound but I do want to avoid the distinct structural weakness. This is one of many instances, where practical prefer- ences come into conflict with organological knowledge. It is up to everyone alone to weigh up, whether the weakness of the Italian construction should be accepted for a pos- sible advantage in sound, or whether it is merely an unquestioned tradition.

    This is a good moment for a pedagogical remark. I have always been afraid of two mis- takes: a weak static (resulting in a poor tuning stability) and an unreliable action. Working alone and after completing over a hundred instruments, I would otherwise long

  • ago have been forced to stop building any new ones and to devote my time exclusively to the maintenance and repair of my own production. So I strongly recommend sparing no effort when thinking about and planning the important working steps.

    Let's return to the work. Now finally the right side of the bottom is cut to size along the bentside, using a right angle to check whether the edge lies directly under the liner at all places. Now the skeleton of your harpsichord is complete. The advantage of this method is, that you can assemble all the parts very precisely, which is much more complicated when building the parts into a complete case. Also you can secure all the joints between the liner and the knees and at the corners of the different parts of the liner with addition- al dowels.

    Interior construction by Christian Zell(1728) developed from Italian models

    Now the sides are glued on to this construction. You start with the bentside, which also is left a little longer and wider than needed. One could say the thinner the bentside, the less precisely it needs to be bent. There are different methods of bending. Thin Italian bentsides can be ironed with water on top of a form. An advantage of this method is, that the dampness and the heat are applied at the outside of the curve, which later becomes the inner surface of the bentside. So most of the stains that are easily caused by this pro- cedure, will later be hidden inside the instrument. One can also use an electric iron spe- cially designed for bending the sides of string instruments. Here one needs to take the biggest model for double basses. However with this method, eventual stains would later appear on the outside of the instrument.

    The upper moulding of French or Flemish instruments is best applied before bending the bentside2, particularly if you want to use a moulding plane and no router. These thicker bentsides can also be bent by ironing, only it costs more time and requires much force3. A thicker bentside can instead be glued together in several layers on a form4. The most elegant is the historical method of soaking the wood for at least ten days in water and clamping it to a form afterwards. Here, much time and good planning in advance are needed. The bending itself requires a lot of force. Nevertheless it is, of all historical methods, the least exiting one. Because the soaked wood remains soft, there is sufficient time to place and tighten one clamp after another, (in contrast, steam bending requires

  • quick work). The most time consuming part of this method is the drying. The historical method of drying the clamped bentside on a baker's oven seems too crude to me5. It is better to leave it - clamped - to dry in the attic for about half a year. Through the con- stant temperature change of day and night the wood will dry most effectively. Laminated gluing as described above gives the most stable and regular results. Another method is bending with fire, as used by the Ruckers. I have tried this method - it works well and safely (but only in the open air without a fire risk) but also here, much force is needed. The inner side of the curve is heated with a blowlamp (historically with brushwood) and simultaneously soaked with water. It is actually better to soak the plank some days in ad- vance - this will help avoiding burn stains on the surface. This method only works for harpsichords that are to be painted, because some stains cannot be avoided.

    After bending, no matter which procedure was used, the bentside must rest as long as pos- sible, to level out the humidity in the wood. Ironing adds another insecure element: either the wood is too damp or, considering the work of the hot iron, too dry. In any case, the water will be distributed unevenly in the wood. Laminated bentsides will, on the other hand, always be too damp, since the glue will have brought excess moisture into the wood.

    Now the prepared bentside is clamped dry into place. Below, you drill holes for screws through the bentside into the bottom. These (in combination with hardwood buffers) are used instead of clamps, which can only be attached at the bass end of the bottom. The lin- er and the knees, however, present no such problem; here you can use clamps. Only when everything fits perfectly should one start gluing. After drying, the screws are replaced by trenails. Often, or perhaps always, historical builders attached the bentside to the bottom with iron nails. I am not really fond of this carefree nailing. In an original, I saw dozens of very pointed forged nails that attached the lower moulding, protruding more than 20mm at the inside of the instrument. My trenails usually are covered by the moulding. Otherwise they should be distributed evenly, and the visible square surfaces should be placed edgewise. This looks both decorative and functional.

    Now the glued-in bentside is cut exactly to fit, and the joints for the cheekpiece and tail- piece are made. Thin sides are usually mitred, but for thicker planks I prefer the manner used in Ruckers' harpsichords. This is a combination of a mitre and a lap, strengthened by trenails. I think that this joint is more stable than dovetails. On the other hand it is only useful for painted instruments, because even a very neat joint in this manner looks all too functional. All these joints can be made on the glued-in bentside, simultaneously with cutting it to size. This may be more complicated than preparing everything beforehand, but it is almost impossible to glue a prepared bentside exactly into place without it slip- ping ever so slightly. The front edges of the cheekpiece and the spine are cut exactly to size after making the joint; this presents no special problem, since nothing may slip dur- ing the gluing anyway. Slip can be avoided by pressing the pieces (for instance with slightly diagonal clamps) into the joint.

  • THE CASE 179

    The thin sides of Italian instruments can - at their upper edge - be secured with a few lamellae made from 2-3mm thick wood. The edge is sawn in diagonally until well into the inner moulding. Then the lamellae are glued in, and covered by the outer moulding. I need not describe the mouldings, the nameboard or the jackrail attachment. Also, the different set-up of a "false inner-outer" case will be self-evident.

    Lamella

    Some German harpsichords with thin sides, doubled only above the soundboard, are ex- actly constructed according to the Italian false inner-outer principle, and to be built in just such a manner. This applies for instance to instruments by Christian Zell and Michael Mietke; other instruments resemble Flemish, French, or later English harpsichords, and are better built from the outside inwards.

    This description of one harpsichord type, and my comments about certain variants, helps to construct all the important options from the Italianate building tradition. The result is a small, light continuo harpsichord, with no historical instrument as a direct model; yet it could have been built by most of the old masters. If one has access to cypress wood, it will be almost like the real thing. But this is not strictly necessary; many Italian harpsi- chords have spruce soundboards, and there are also many with sides from pine (perhaps the Mediterranean variant) or maple. Such a new construction is no contradiction to ex- act copies, but both are possible ends of a continuum of options. So instead, one also could only re-calculate a given original, correct obvious mistakes and perhaps change a few technical details, like the stop levers. Or one could combine several historical ex- amples to a similar new instrument.

    I want to add a short comment on experiments. I recommend giving one's curiosity all the space needed. Do try out things. Experiment. Develop and exercise your practical cu- riosity; by doing so, you speed up the accumulation of experience. Also many results or solutions simply do not reveal themselves at the drawing board. Yet I hesitate to recom- mend my personal way of tackling this issue. I have experimented all my life in almost every instrument, sometimes even with two experiments in one instrument. The sleuth- work afterwards, to find out which step had which result, was most satisfyingly thrilling. But such an excessive interest in experiments requires a good feeling for not overstep- ping the mark, and for not putting the quality of the work at risk, and a sort of focused fantasy to avoid useless experiments.

  • The structure of a Flemish harpsichord

    I will now outline the Flemish construction, from the outside inwards, and I will chose a description, which emphasizes the succession of the working steps in a relaxed manner.

    1. The wrestplank, the upper and lower bellyrail, the lower frames and two strips of wood, which will be placed on both sides between the keyboard frame and the sides, are cut to size and planed. A moulding is applied to these two strips, and the wrestplank is best veneered (across the grain) at this stage. All the sides are now prepared, and the bentside bent. The wrestplank and the lower bellyrail, the lower frames and the nameboard need to be 12-14mm wider than the inner width of the case.

    2. According to these 12- 14mm, one cuts grooves of 6-7 mm depth into the sides (if the space between bellyrail and first lower frame is planned to be accessible, i.e. if one plans a 'Ruckers box', one needs to cut a square opening into the spine).

    3. The wrestplank, the nameboard, the lower bellyrail and the first lower frame are assembled without glue, and holes for trenails are drilled into the sides from the outside.

    4. Now all these parts can be glued together with the spine and the cheekpiece. 5. The moulded strips are glued inside the front of the case, and their lower edges

    are planed flush with the edges of the sides. Another two strips are fitted from the lower edge of the wrestplank to about 10mm lower than the top edge. These fill the gap to the upper bellyrail and serve as a rest for the upper guides.

    6. The scarf joint between the bottom and the front bottom is prepared, and the front bottom is glued under the front edge of the sides, and secured with trenails.

    7. The combined part is placed on the drawing and the bentside is fitted in the correct angle, according to Rucker's principle in a combination joint (mitre and lap; the bass edge of the bentside is still left a little longer). The lower frames are let into the spine and bentside, and assembled without gluing to accommodate the drilling of holes for the trenails.

  • THE CASE 181

    Now the bentside and the lower frames are combined with the first part, glued into place and nailed. The trenails used for the sides into the frames, and through the bottom into the sides should be about 4.5 to 5 mm thick; those used to secure the edge between the bentside and the cheek that are driven into the end grain of the cheekpiece (and those used correspondingly at the tailpiece), should not be thicker than 3 rnm. When gluing, a perfectly straight plank should be clamped on its edge under the spine to keep it straight during the assembly. This plank should be in place until the upper braces are glued in. The bass end of the bentside is cut to fit the drawing, and the tailpiece is fitted, in the manner of the treble corner. The tailpiece and the spine are mitred; the acute angle at this edge makes the gluing surfaces sufficiently wide. Also, after having completed the other joint to the bentside, a mitre is easy to make. All the pieces of the liner are fit and glued into place (one can use trenails like the Ruckers', but this is not strictly necessary). The best order is tailpiece, bentside and then both the straight pieces. It is more secure to fit all parts that support the string tension behind the ends of the other parts - even though the old builders were unconcerned about this detail. The u