- Sealed machines are permanently lubricated and enclosed in a metal case that screws onto the back of a guitar's headstock. There is usually an adjustment screw on the end of the tuning knob. Since you can't open them, you can't grease or repair them. If they stop working, you'll have to replace them. Most electric and steel-string acoustic guitars come with sealed tuning machines. They are not available for classical guitars.
- Exposed machines are not sealed, and need to be lubricated occasionally. They are also screwed onto the back of the headstock. Sometimes manufacturers try to make them look like sealed machines by hiding them with a screw-on cover. You can tell the difference because they don't have an adjustment screw on the end of the knobs. If you remove the cover, you'll find an adjustment screw underneath.
- Classical-style machines arealso not sealed. They often come as two sets of three tuners, attached together on a strip of metal which is screwed onto the side of the headstock. They are not covered, and should be cleaned, lubricated, and adjusted periodically.
If your tuning machines are working smoothly, leave them alone. Don't try to do anything to a tuning machine without loosening the string it's attached to. The best time to clean and lubricate the machines is while you're changing your strings.
To lubricate and adjust tuning machines:
- Loosen or remove the string. Remove the machine's cover if it has one.
- You'll see a gear with a screw holding it on. Unless the machine is actually jammed, there's no need to remove the screw. (If you do, be careful. Don't lose the peg, which will fall out of the headstock when you take the screw out.)
- Use something lint-free and a tiny bit of rubbing alcohol to remove lint and dirty grease from the gears.
- Replace the gear (and the peg) if you removed it.
- Whether or not you removed the gear, this is a good time to adjust it. Use a screwdriver and tighten it until it just seats, and then a tiny bit more.
- Regrease the gears withVaseline, light machine oil, or graphite. Replace the cover if there is one.
If one of your tuning machines is seriously jammed or broken, you'll have to replace it. If you don't have sealed tuners already, this might be a good time to buy a whole set and replace them all at once. A set of sealed tuning machines does not coast a lot, and it might be worht looking into buying them.
Take one of your old tuning machines off and bring it with you to the guitar shop. The part of the tuner that goes through the headstock varies in diameter between varieties and brands of tuning machine. Be sure to buy a replacement that is the same size or larger. (If it's smaller, it won't fit snugly and the tension of the string will snap it.) If the new tuner is larger than the old one, you will also need to buy a reamer. (A tool for making small holes larger.) If the new tuners have screws in different places than the old tuners, buy some wood putty to fill in the old holes.
To replace tuning machines:
- Loosen or remove the guitar string.
- Unscrew and remove the old tuning machine.
- If the screw holes aren't going to line up, fill the old ones with wood putty. Allow the putty to dry thoroughly before you continue.
- If the hole in the headstock is too small for the new machine, use a reamer to carefully enlarge it. Do this a little at a time, and be sure you aren't making the hole lopsided. The new machine should fit easily in the hole, without forcing and without wobbling around.
- Install the new tuning machine.
Tuning machines are not expensive, and are quite easy to replace. If you have a broken tuning machine, it's probably best to replace it rather than trying to fix it. Sometimes a tuning machine just needs to be greased or unjammed, but usually when they stop working you should just put on a new one.
There are three kinds of tuning machines:
