Despite the relative simplicity of design--simpler than, say, your adjustable saddle--machine heads are actually one of the more complex issues of guitar maintenance.
Simple cork-screw cranking devices into which strings are fed to accommodate proper tuning, machine heads are prone to issues other guitar hardware is not. And while adjustable saddles, for example, require some relatively vigilant and thoughtful care to retain their integrity, when it comes to machine heads, this is a case where less attention is usually better.
What you’ll need:
· A clean, soft rag (an old, cotton T-shirt works great--minus the rough seams and rock & roll iron-on transfers--as do flannel night gowns and old cloth diapers. Flannel is quite inexpensive to buy by the yard so that may be the most practical).
· Petroleum jelly (Vaseline)
· A small artist’s brush (buy a good one so that the hair won’t fall out after a few usages or while you're using it)
· A toothpick (unused)
The first step to maintaining your machine heads is to establish what type of machines you have: closed or open. “Closed” machines (meaning you can't see any gears) are deemed “maintenance free.” Aside from the occasional wiping of the gear casing with a clean cloth to keep sweat, grime, and the elements from corroding the finish, and maybe a little occasional detailing with an artist’s brush to keep dust from accumulating, they’re basically self-maintaining.
“Open” machines, however, are a different story. And a cautionary tale at that.
Although “open” machines (meaning you can see the inner mechanisms) would seem to need some pretty thoughtful maintenance to assure that they continue to do what they do proficiently, over maintenance can take years off their life expectancy and make them a nuisance to use until you finally replace them.
Since open machines have no outer covering to be concerned with, it is the inner mechanisms that require periodic attention--albeit sparing attention. Aside from using an artist’s brush to remove any dust that may be accumulating (something you should do each time you change strings), the only other thing required is to apply a minute amount of petroleum jelly to the gears every few months; minute being the operative term. Bear in mind that since these gears are exposed, any lubricant you apply is likely to attract dust and dirt particles. Therefore, you want to learn to apply the least amount of Vaseline possible (via a toothpick and NEVER a Q-tip) that will keep the gears turning smoothly--without excess. Make no mistake, if you leave too much lubricant on a gear, dust and dirt will adhere and lead to mechanical breakdown. And while the gear mechanisms of open machines are not complex, they are invariably easier to replace than repair.
The term “maintenance,” however, can take on a somewhat different meaning when it comes to machine heads. For example, if you notice that your guitar seems to be going out of tune more often than usual, you have to consider whether your machines are wearing out or just need a little adjustment. Over time--regardless of whether they are “maintenance-free” machines or open machines that have been reasonably maintained--a time will eventually arrive when the gears wear out, become corroded, and begin to slip. When this occurs--and it never occurs at a convenient time--the one advantage to having open machines is that you may be able to pinpoint the slippage and determine which gear is faulty. And under these circumstances, you may be able to compensate for it by simply tightening the screw. (Most are Philips heads.) However, if the problem isn’t obvious (which may allow you to replace a single machine) and doesn’t correct itself (which is seldom the case unless the culprit is actually a nut or saddle problem), you’ll most likely have to replace all the machines. Thus, it’s wise to be thoughtful about machine head maintenance from the start.
Forty years experience as a professional guitarist
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