There are a number of reasons that a guitarist might replace parts of their instrument. Damage or wear and tear can force replacement, but equally well, alterations can be made for improvement and upgrading or merely to change the guitar's appearance for cosmetic reasons. Some upgrades, modifications and replacements are best left to professional technicians or luthiers, but others are easily within the capabilities of anyone with reasonable toolworking skills. We will work our way down the guitar, from end to end, and consider which replacements fall into which category.
The headstock carries the machine heads (sometimes referred to as tuning pegs or tuning pins), and replacement of these with like-for-like replacements is a straightforward task. Having removed the string(s), undo the nut on the front of the headstock around the tuning post. Unscrew the machine head from the rear of the headstock, and tap the top of the tuning post to push the machine head out from the rear of the headstock. To replace, insert the tuning post from the rear, secure the rear retaining screw, and replace the front nut around the tuning post. If the replacement heads aren't a direct replacement for the originals, it may be necessary to either enlarge the hole for the tuning post, drill new pilot holes for the rear screws, or both, and there may be visible holes left behind on the rear of the headstock from the original heads.
Most guitar headstocks are fitted with a string tree to maintain the strings in proper alignment with the tuning heads. With the string(s) removed or loosened, replacement is merely a matter of unscrewing the original and inserting the replacement.
If the guitar is fitted with a truss rod, it will usually be hidden behind a truss-rod cover, and replacement of this, usually for cosmetic reasons, is an easy task. Most covers are secured with one to three screws, and the original is easily removed and replaced.
The Neck, Fingerboard, and Body
With regard to the neck and fingerboard, generally speaking, matters here are best left to the professional luthier or guitar technician, and are outwith the scope of the amateur repairer. Dressing of the frets (filing them down to optimise their height), fret replacement, alteration of nut height, or nut replacement are all tasks which require skills that generally take years to acquire.
Replacement of the neck or body of a guitar is possible, but usually only for electric guitars. Acoustic guitars are, in the main, built with glued neck joints, and only in the most extreme cases of damage would a luthier attempt to rebuild one. Whilst some electric guitars are similarly built with glued neck joints, or are of a through-neck construction where one continuous piece of wood or laminate runs the full length of the instrument, many electric guitars, particularly Fenders, have necks which bolt or screw on to the body. In Fender's case, this was a deliberate design philosophy. If the neck or body were damaged beyond repair, or worn out, the owner would merely separate one from the other and substitute a replacement for the damaged or worn original. With a bolt-on neck design, the guitarist can substitute the neck, perhaps changing from one with a maple fingerboard to one with rosewood or retain the neck and exchange the body, perhaps for one made from different wood(s) or with a different finish. If the body is of a directly matching style, the hardware can be removed from the original body and transferred to the new.
With the strings removed, the bolts or screws securing the neck are unscrewed from the rear and the new neck and/or body bolted or screwed together. Depending on manufacturing tolerances, there may be some variation in the neck angle once the new combination is assembled, and it may be necessary to adjust this with shims between the neck joint and body. This will only become apparent once the guitar is restrung, and some trial and error may be called for here, so try experimenting with different shim depths.
There are, generally speaking, very few parts replacement options for acoustic guitars that won't require a technician's or luthier's skills. Only perhaps for some electro-acoustic guitars should the amateur repairer consider like-for-like replacements, perhaps of minor components, such as output sockets, volume controls, or strap buttons.
Pickups, Electronics, and Other Hardware
Many electric guitarists will, if upgrading or modifying their guitar, choose the replacement/upgrade option that will have the most significant effect on the sound of the instrument – pickup replacement. The pickup is one of the key elements in the sound of an electric guitar, and replacing one or more of these will be sure to change the character of the instrument. Of course, like-for-like replacement, in the case of a damaged or worn pickup, will retain broadly the same character, but the owner should be prepared for at least minor tonal change.
Replacement of a pickup will require basic soldering skills but, apart from this, is well within the capabilities of the amateur. Most pickups can be unscrewed from the scratch plate or body of the guitar and lifted out to reveal the wiring recess, and the pickup lead will most likely be soldered directly to the volume or tone potentiometer or an electronics board if fitted. Access to the solder joints will vary depending on the model of guitar but for a solid-body model will usually involve removal of a cover plate on the rear of the guitar. Desolder the wiring, remove the original pickup, solder the lead for the new pickup in the same place, and secure the pickup to the body or backplate. The process for semi-acoustics is more complex, and requires removal of the whole wiring loom through the pickup mounting holes.
Scratch plates are a popular replacement item, especially on solid-body models, and replacements are usually made for cosmetic reasons, the typical aftermarket replacements being in significantly different styles from the makers' originals, often in metallic or mirrored finishes. Usually, the scratch plate can be removed with pickups in place, the pickups moved from the original plate to the new, and the new plate put in place.
Control knobs for volume and tone can be replaced if damaged or for cosmetic reasons. Most designs are a push-fit onto the shafts of the volume or tone pots. Remove the originals with the aid of some twin-core electrical flex. Split the flex in the middle, and wrap each side under the control knob to pull it away from the shaft. Push the replacement onto the shaft in a reversal of removal.
If the guitar is fitted with a tremolo arm, there may be different designs available for the guitar. In the case of the Stratocaster design, removal is merely a case of unscrewing the original and inserting the replacement. Other designs may require removal of the whole tremolo assembly.
Other miscellaneous components such as jack sockets, strap buttons etc. are, in the main, easy to unscrew and replace. The jack socket, when removed, will need to be unsoldered from the wiring loom and any replacement soldered back into place. Strap buttons can be upgraded with lockable types and are easily unscrewed and replaced.
Finding Guitar Parts on eBay
From the eBay home page, select All Categories, then select Musical Instruments. Some sellers may list parts under the general Accessories/ Equipment category, but in the main, they will be found under Guitars, Accessories, and Parts. Searches can be further refined by brand – Fender or Gibson, say, or by part type – Scratch Plates or Control Knobs, for example.
Replacement of many elements of an electric guitar, whether for reasons of damage, wear and tear, upgrading, or merely cosmetic improvement, is, in many cases, well within the abilities of the amateur repairer.