Overwater Guitars' Chris May resumes his series on guitar building. This month - Design Criteria

To those of you who noticed, I must apologise for my absence from the last issue. Things down here in guitar-making land went quietly barmy last month, and then, when they were at their most hectic, I had a fight with a chain saw. Needless to say, I lost; and was left with several stitches and a lot of extra washing for my trouble!

I wouldn't exactly say we're back to normal but at least I've re-established enough sanity to assemble the notes I made back in February, when I'd decided to ponder the various aspects that go into the design process of a musical instrument - and in particular, of course, the electric guitar.

I remember, some years ago, reading in one of the 'dailies' a report from a major motor show. The correspondent, musing on the diversity and varying practicalities of the vehicles on display, observed something to the effect that 'if a motor car's primary function was to convey its occupants from point A to point B, then logically they'd all be built along the lines of a jeep. But it's not - and they are not'. A very similar analogy could well be drawn with musical instrument design. Although, technically speaking, a grand piano need not have flowing lines, elegantly carved legs and a highly polished finish, I doubt whether prospective purchasers could be persuaded to part with the not inconsiderable sums involved if these features were absent.

However, 'classical' instruments, although varying in detail, are usually built to a fairly rigid, predetermined pattern. The classical guitar, for instance, has changed little in shape, constructional method or dimension since Torres formally laid down its specification nearly a century and a half ago.

The electric guitar, on the other hand, is quite another story. Throughout its short history this instrument has gone through so many metamorphoses that instruments supposedly peers, would be (to the untrained eye) hardly recognisable from each other.

This freedom - or apparent freedom - from rules of design is, of course, due at least in part to the electric guitar not needing to project the volume of its sound in the form of direct acoustics. The mass and vibrance of the material from which an instrument is made does to a large extent govern the tonal quality of the sound it produces; but, compared to instruments with a longer ancestry, there aren't the points of reference to guide the electric guitar maker as to how a finished instrument should either sound or look. Having said this, it has to be admitted that, until quite recently, most electric guitars tended to be categorised as derivatives of those two American giants, Gibson and Fender.

At this point, I think it would be useful to try and make a distinction between points of design which are present because they enhance the instruments, and those which are concerned with ease of production. The 'Fender-type' instrument, with its modular construction, is still the industry standard for the mass-produced guitar. Some 35 years after its inception, the host of instruments (both Western and Oriental) which follow the basic pattern almost exactly is enormous. The Fender approach is a classic example of a design that caters not only for the end user, but also (and almost more importantly) the efficiency of the production method. These guitars are designed specifically to be machine-made with semi-skilled operators. The craftsmanship is centred around the original design, production engineering and choice of materials. To a large extent, it's been a case of working out an efficient production method and then designing an instrument that will fit in with that method.

The other extreme is to design a 'no compromise' instrument, and subsequently work out how it's to be produced. Most commercially manufactured guitars fit into a sliding scale between these two points. The amateur maker, too, has to take these factors into consideration; for it would be pointless to design an instrument that the maker has neither the skill nor the facilities to build!

And so to actual design. There are two main considerations to be borne in mind when designing a guitar, apart from the actual making process. They are: (i) its musical quality; the tone and sound, scale length, playability etc., and (ii) its physical characteristics; strength, stability, weight, balance and so on.

Of course, these two areas are considerably interlinked. The materials used will have a bearing on both the sound of an instrument and its weight and stability (I went into some detail of the physical properties of timber in Part 2 of this series). Generally speaking timber for neck construction should be reasonably dense, straight grained and very stable - although not too heavy, as this may affect the balance of the instrument as well as the overall weight. The bulk weight and shape of the guitar body should be sufficient to counterbalance the neck length, so that the instrument is comfortable at an angle of around 45 degrees when either hung from a strap or balanced on the player's knee. Neither should the weight be too great - an electric guitar does not (contrary to myth!) need to be enormously heavy in order to sustain well. This has much more to do with the materials and construction of the instrument than its sheer bulk.

One more point on the subject of balance. Remember that machine heads and other hardware will alter the centre of balance, so their weight and position should be taken into consideration well before the time comes to screw them on.

Neck specifications, fingerboard widths and fretting are very much a matter of personal preference, but first-time makers would be well advised to select an instrument that they have access to and that has a neck which suits them, measure it carefully and base their own work around it. Even now, it never ceases to amaze me how a 1/16" difference here and there on a neck can change its feel completely.

If you are going to buy in your hardware (and there is an enormous variety on the market nowadays), select it before you begin building for it will affect many aspects of construction, the most major being the neck angle - and this is critical. A stud mounted type of bridge will not fit onto a guitar designed for a flat-bottomed type, and vice versa, without a great deal of trouble.

Next month. I'll explain in detail and with illustrations, how to work out the neck/body construction in relation to the hardware. In the meantime, watch those chain saws, won't you?!