Tuning instability, slipping gears, broken tuner buttons — these are all great reasons to give your headstock a much-needed makeover. Upgrading your guitar tuners can be a fun and easy way to solve common tuning stability problems. The endless sea of tuner replacement options may seem daunting, but here are some tricks of the trade to help you determine which tuner is right for you.
Which Tuner Is Going to Fit?
An upgraded tuner that will drop into your guitar without some kind of modification is hard to find. Replacing your tuners will usually require you to either drill a new pilot hole for the mounting screw, ream the tuning post hole, or both. You may want to avoid modifying the headstock if you have a collectible or vintage guitar, as it could depreciate its value. Don’t let this discourage you, though, because there are a lot of aftermarket vintage tuners that just might work.
Take a look at your tuners. If you have an open-back tuner where the gears are exposed, it’s a safe bet that you have a vintage-style tuner. Vintage-style tuners will typically have a press-in bushing that secures the tuning post, like the one shown below.
Pro Tip: If your new tuner hardware matches your old hardware, leave the old press-in bushing installed. This way, you only need to replace the tuner itself and you won’t risk chipping the finish when removing the old bushing.
Sealed-gear tuners are exactly what they sound like. The gear is protected inside a die-cast housing. The tuner is secured to the headstock by a threaded collar that surrounds the post and can typically be tightened or removed with a 10mm nut driver or deep-well socket.
Changing tuners from a press-in fitting to a threaded collar will require you to enlarge the diameter of the tuning post hole. Enlarging the hole with a tapered reamer will allow the threaded collar and tuning post to fit. If you’re going to do this, be sure that you’re testing the fit of the new tuner regularly so that you don’t oversize the tuning post hole.
Mounting Screw Location
If you take a look at the back of your headstock, you’ll likely see some screws holding the tuning machine in place. These mounting screw locations will vary from brand to brand. Most often, upgrading to a new brand of tuner will require drilling a new pilot hole and installing the provided screws in the new location.
To do this:
- Find a drill bit that is slightly smaller than the screw you intend to install into the headstock. When the bit is held up to the screw, you should see the screw threads extend past the bit on both sides.
- Tape off the drill bit to the length of the screw so that it will act as a depth-stop and prevent you from drilling in too far.
- Once your new tuner is properly aligned, you’re ready to drill your pilot hole and install your new screw.
This will likely leave the old holes exposed. It’s a good idea to glue in a small dowel (or toothpick) cut flush with the headstock to plug those holes and prevent moisture from creeping in. If you’re a perfectionist, you’ll need to match the wood type and color before refinishing the headstock to make those holes completely disappear.
If your replacement tuner is the same brand as your old tuner, you’ll want to be sure the locations of the screw tabs match. The photos below are examples of different Grover Rotomatic tab locations and should give you an idea of what to look for when purchasing your new tuner. Be careful though — different brands will have similar tab locations, but will rarely be identical.
Although not as common, there are tuners that will utilize one or several indexing pins to keep the tuner secured to the headstock. This is especially popular with Fender guitars. If you’re interested in retrofitting a tuner with an indexing pin, you can depress the tuner to the back of the headstock so that the pin leaves a shallow impression. You’ll use this as your marker to drill your pilot hole. Be sure that you repeat step 2 (above) and mark your drill bit depth with tape to prevent drilling too far.
Locking tuners can be an enormous benefit to your guitar and guarantee better tuning stability. They also make restringing your guitar a breeze because there’s no need to wind your string down the post. Locking tuners have a mechanism in the post that, when engaged, locks the string into place and eliminates string slippage.
A Word on Gear Ratio
The gear ratio of your replacement tuner will determine how many rotations of the button it takes for the post to turn 360 degrees. For example, a tuner with an 18:1 gear ratio will require 18 turns of the button to reach a full rotation of the post and will give you more precise tuning than a 12:1 ratio. Graph Tech offers a set of tuners that have different ratios for different tuners (depending on which string) so that you get equal pitch response across all strings.
Let Us Tune It Up for You
Hopefully this article taught you a little bit about how your tuner is secured to your guitar and the modifications necessary to make your new upgraded tuner fit. The Sweetwater Guitar Workshop is always available to help with any upgrade or hardware installation you might need some assistance with. Don’t hesitate to call your Sweetwater Sales Engineer at (800) 222-4700 if you need accessories or replacement parts for your guitar.