Press Fit Tuner Buttons on Vintage Guitars

Restoring vintage guitar tuners is one of the most satisfying luthier tasks. You’ll go from crusty, corroded hardware to gleaming tuning machines with fresh, bright buttons. In our last video, we cleaned a set of tuners using WD-40 and removed some of the surface rust & grime. Now comes the final step: installing new replacement buttons onto the tuner shafts.

While there are several methods floating around online, including heating the shaft with a soldering iron, using a flame, or soaking in hot water, there’s a simpler, more controlled approach that doesn’t risk damaging the plastic or metal. In this guide, we’ll walk you through the press-fitting method using a vice and a simple drill bit to ensure your new buttons sit perfectly and stay put.

Why Press Fitting Works Best for Tuner Buttons

The replacement buttons you’ll source from retailers like Stew-Mac have a rectangular hole designed to fit over the flared, squared-off end of the tuner shaft. This design creates an interference fit. Once fully seated, the button locks itself in place mechanically. The challenge is getting the button onto that shaft without forcing it so hard that you crack the plastic or strip the threads.

Press fitting using a vice gives you complete control over the pressure. Unlike heat-based methods, which can warp plastic or damage vintage finish, or soaking methods that are unpredictable, a vice lets you apply steady, even pressure while keeping both components perfectly aligned.

Step 1: Slightly Enlarge the Button Hole

The first step might seem counterintuitive. You’re going to drill out the hole in the button slightly. Don’t worry; you’re not enlarging it much.

Use a 7/64″ drill bit (or an 1/8″ bit works too. Experiment to see what fits your specific buttons)
Clamp the button securely in a hand vice to keep it centered
Drill gently and slowly into the button’s hole. Just go a few millimeters deep
The goal is to remove just enough plastic to allow the button to start engaging the tuner shaft without resistance

This small step makes a huge difference. By pre-enlarging the hole slightly, you ensure the button centers itself on the shaft before the heavy clamping pressure begins. This prevents the button from tilting or binding as you tighten the vice.

Step 2: Set Up Your Vice for Press Fitting

You don’t need an industrial-grade vice for this job. A small machinist’s vice or even a basic clamp vice works perfectly.

Mount the vice securely to your workbench
Open the vice just wide enough to fit the tuner shaft and button assembly
Look for a vice with smooth jaws rather than serrated teeth. Serrated jaws can mark or damage the metal
If your vice has toothed jaws, place a thin piece of brass shim stock, plastic or even scrap wood between the jaws and your tuner to protect it

Step 3: Insert the Assembly and Begin Clamping

Now it’s time to bring the two pieces together.

Position the tuner shaft in the vice jaws
Slip the pre-drilled button onto the shaft
Hold the button with one hand and the tuner with the other to keep everything aligned
Begin tightening the vice slowly and steadily. No sudden jerks

As you tighten, you’ll feel the button begin to seat onto the flared end of the shaft. The squared-off ends of the shaft will gradually press into the plastic. This is where alignment matters most. If you feel the button starting to bind or tilt, back off the vice, reposition, and try again.

Step 4: Apply Final Pressure Until Locked

Continue tightening the vice gradually until you feel solid resistance. You’ll know it’s done when:

The button no longer rotates on the shaft
The metal shaft ends are visibly embedded in the plastic
The button feels rock-solid and immobile

You should apply enough pressure that removing the button requires significant force, think pry bar or claw hammer levels of effort. This ensures your buttons won’t spin or loosen during normal use.

Step 5 (Optional): Reinforce with Super Glue (Recommended)

While the mechanical press fit alone is strong enough, adding a small dab of cyanoacrylate (super glue) in the seam between the button and shaft provides extra insurance against the button ever working loose. This is especially wise if your vintage guitar will see regular playing.

Apply just a tiny amount of super glue around the seam
Wipe away excess with a cotton swab
Allow 5–10 minutes for full cure

Pro Tips for Flawless Results

Key takeaways:

Drill straight: Use a drill press or jig to ensure your pilot hole is perfectly centered. A crooked hole will cause binding during press fitting.

Keep it cool: Unlike heat-based methods, press fitting generates minimal heat and won’t damage plastic or vintage finishes.

Work at your own pace: Slow, steady vice tightening beats rushing. You can always apply more pressure; you can’t undo stripped plastic.

Protect your vice jaws: If your vice has teeth, use shims to prevent marring the tuner shaft.

Test your fit first: Before final assembly, do a dry run (without glue) on one button to verify your drill bit size is correct for your specific buttons and tuner shafts.

Frequently Asked Questions

What size drill bit should I use?

A 7/64″ bit works well for most standard tuner buttons. However, every vintage tuner and replacement button combo is slightly different. Start with a 7/64″ and test on a spare button if you have one. An 1/8″ bit is also a safe alternative. The goal is to remove just enough plastic to let the button start engaging without forcing.

Can I use heat instead of a vice?

Heating the shaft with a soldering iron or flame and melting the plastic on is possible, but it’s riskier. You can easily warp the button, overheat the shaft (affecting hardening or finish), or create uneven seating. A vice gives you much better control and repeatability, especially if you’re working on multiple tuners.

What if my button cracks during press fitting?

If a button cracks, you’ve likely applied pressure too quickly or the hole wasn’t drilled straight. Make sure to drill perpendicular to the button face using a drill press or jig. Also, tighten the vice in small, even increments. If a button does crack, simply order another and try again with adjusted technique.

Do I need to use super glue?

No, but it’s highly recommended. A properly press-fitted button will hold securely through mechanical interference alone. However, super glue adds a permanent safety margin and prevents any possibility of the button working loose over years of playing and tuning.

How long does the whole process take per button?

Once you have your vice set up, allow about 3–5 minutes per button (drilling, positioning, clamping, and gluing). The actual pressing takes only 30–60 seconds; most of the time goes into careful alignment and letting glue cure.

Restore Your Vintage Tuners with Confidence

Pressing new buttons onto vintage guitar tuners is a straightforward process when you use the right approach. By drilling a small pilot hole and using a vice to apply steady pressure, you avoid the risks of heat-based methods and achieve reliable, lasting results. Your restored tuners will look and function like new for decades to come.

See the Full Build

The complete restoration process is documented on the Zwitch Guitars YouTube channel.

Watch the video →

Questions about press fitting plastic buttons on vintage guitar tuners? Leave a comment on the video or get in touch through the contact page.