Guitar Workshop: Top Nut & Tales
A nut is so much more than a bit of plastic: alternative materials often make a huge difference, and an expert replacement can transform a guitar…
Experienced guitar repairers have many tricks up their sleeve to get that extra ounce of performance out of an instrument. As you’ll have twigged by now, the standard of set-up given to most new guitars is, unfortunately, generally low. Budget instruments in particular are often hurriedly thrown together to keep costs down and production rates up. This may be frustrating for the musician, but it does mean that first guitars can be affordable – and in most cases the instrument can be later worked on by a pro repairer to iron out the nastier foibles.
In general, problems on affordable guitars tend to arise because although the hardware – bridge, tuners, top nut, pickups, electronics and so on – may look identical to that on a guitar costing 10 times the price, in reality it lacks the degree of engineering of the components it sets out to emulate.
Cheaper Strat-type single-coil pickups, for example, often use one or two ceramic magnets underneath six steel polepieces to power the pickup. Although the pickup works fine and reliably with a reasonable output, the sound quality is often on the ‘scratchy’ side… and not very musical. Again, cost is the culprit. Ceramic magnets are very cheap, alnico magnets – used on more musical single-coils – are more expensive; and when you’re trying to make a guitar that’ll retail under £200, every penny counts.
Another example is the nut, which on cheaper guitars is more often than not a mass-produced one-size-fits-all moulded item. The material used for the top nut actually plays a very important role in tailoring the sound of the guitar. Nylon-like plastic – as used on the worst moulded top nuts – is just not up to the job; often you’ll even find nuts which, when you lift them out and turn them over, are hollow underneath. As it’s universally agreed that the top nut (and, on acoustics, the bridge saddle) should be made from a constantly dense material if the instrument is to have any strength of musical voice, these sham nuts are ludicrous.
Traditionally, a guitar’s nut was made of either bone or ivory. Times and attitudes change, though, and nowadays there are synthetic substitutes which can replace these natural materials. ABS plastic is very popular; it’s extremely dense, easily and accurately workable with a saw or file, while molecularly it’s very consistent and only mildly porous, making it physically – if not sonically – a better material than either ivory or bone. However, ABS’s extreme density makes it brittle and it has trouble withstanding knocks and bashes without cracking or splintering. To counter this fragility, chemical industry boffins have developed other plastics to emulate bone and ivory such as Corian, Micarta, Tusq and even clever graphite-impregnated variations specially designed for vibrato-equipped divebombers.
Choosing the right material for your guitar is something to discuss with your repairer, as sonic differences between materials is quite marked. Supplying and fitting a replacement nut requires time-consuming precision work, so it’s worth getting the material right first time. Replacing your nut is tricky and requires some highly specialised tools, so it’s really a job best left to a pro repairer. Nuts do wear out; the strings slots eventually become too deep, making the strings rattle against the first few frets.
In dire circumstances low string slots can cause the frets to wear into gullies that run directly under each string.
Unfortunately the only way out of this predicament is to replace the nut and refret the guitar – expensive and unnecessary. Of course, you may just decide to replace the nut because you’ve read this article and discovered that a moulded horror is strangling the tone of your strings at birth. Whatever your reason, discuss the problem with a good repairer and also consider the subject of string spacing,
String spacing isn’t just the physical distance between each adjacent string, it’s also the distance between the outer strings and the edge of the fingerboard – a factor which plays a dramatic part in the overall feel of your guitar. The actual amount you can widen your string spacing is determined by the design of your guitar. Necks with no edge binding tend to have a fairly sharp angle to the fret ends, so that the amount of fret available to play on is nice and wide; conversely, if the fret ends have been heavily dressed or if your guitar has the kind of bound fingerboard edges where the frets stop before the binding starts, your potential playing area will be less.
The primarily danger of widening the string spacing is that the top E string can pop off the edge of the board when playing first position chords or hammer-ons and pull-offs. However, a skilled repairer can often widen the string spacing by moving strings 2, 3, 4, 5 and 6 along, retaining the top string‘s original position – a modification which can sometimes breath fresh air into a guitar that has a cramped first fret feel. A new, freshly cut top nut can make the world of difference to any guitar.
Bad to the Bone – Nut Materials
It isn’t exactly the most PC of choices these days unless it’s been pulled out of an iceberg, yet it’s still regarded as the best material for the job, particularly on acoustic instruments. Ivory, unfortunately, does it all; it cuts easily and can be polished to a high gloss, it’s robust enough to withstand knocks and bangs, and has a high degree of natural slippiness. Sonically it has a ﬂat,
even response across the frequency range of a guitar and thanks to its high density it produces a pleasantly bright musical voice.
Made by GraphTech, this stuff has been standard issue on many guitars for years. It also looks and sounds pretty much like ivory, which is enough for most people. Highly recommended, and not expensive.
Used on many high-end guitars, bone is currently the most popular alternative to ivory. The major difference is colour, both ‘new’ and after ageing. Recommended for all guitars, new or vintage.
An excellent synthetic ivory/bone substitute, used on CF Martin guitars. It cuts and polishes well, but it’s a little softer than bone. Sonically it gives a uniform tone across the strings, although many feel it’s not quite as bright-sounding as bone. Available in both yellowy-white and black, Micarta is good stuff – not least because it’s very affordable.
A fairly new material with the lock and hardness of bone, plus greater density. It cuts well and can be polished to a luscious sheen. Sonically it produces a bright and regular tone across the strings. Recommended, particularly for acoustic guitars.
A dense ‘no-grain’ plastic, and a good starting point with a pleasant tone and off-white colour. It can sound brittle, though.
Graphite top nuts are actually a cunning plastic and graphite mix that makes for remarkably friction-free nut slots – just the job for tremolo players who hate locking nuts. Ideal for slippery tasks.
Mother Of Pearl
Often used on very expensive hand-built banjos and mandolins. It cuts well, looks dazzling when polished and produces a tone that’s very bright, but not harsh. MOP is extremely dense and thus tends to be brittle, but if you look after it you can really turbocharge the treble content of your guitar. MOP top nuts for bottleneck slide players sound very cool indeed. Recommended, but tricky to live with.
Although the heyday of metal nuts was in the ‘heavy is best’ days of the late ’70s and early ’80s, a number of makers still swear by them. Gordon-Smith, for instance, still fit brass nuts to their guitars; other common materials include aluminium, stainless steel and nickel silver. The sound of metal nuts tends to be more middly, with an increase in instrument resonance; the only drawback is friction, and great care must be taken to smooth the nut slots.
Tags: DIY, Guitar Workshop, Home