Locking guitar tuners

[Xoo]

My PRS (Santana SE) is not the happiest at staying in tune at the moment, so I was looking at getting some locking tuners.  Amazon has a mix of Grover (I've heard of them) and various much cheaper unknown brands, which I think I will ignore!  But I have a couple of questions...

- How do I know if what I buy will fit (I think the replacement tuners are all 10mm or 25/64" diameter - pretty much identical, but how do I check the guitar without actually trying)?

- How easy are they to change (my woodworking skills are pretty much negative!)?

- Do they actually make a significant difference to tuning stability?

[Chaps]

I found websites that sell locking tuners that are claimed to be direct replacement tuners for that model. Here is one of them. There is a video there that shows how to install them.

PRS SE Locking Tuning Machines - 3+3, Chrome

[mettelus]

1 hour ago, Xoo said:

- How easy are they to change (my woodworking skills are pretty much negative!)?

A simple screwdriver set with a 10mm socket and #1 (CR-V PH1) screwdriver bit ($10-15 typically) will fit the bill for the hardware if you do not already have those. You want both the socket and screwdriver to fit perfectly onto/into fasteners so that corners do not get rounded over on hardware.

1. With the strings off, use the 10mm socket to unscrew the barrel nut on the head stock face of each tuner. Take this and the washer off the face of each tuner, being careful not to apply undue pressure and avoid scratching any hardware/finish. This barrel nut does the grunt work of the tuner, resisting the tension of the strings against the hole.
2. Flip the guitar over and carefully remove each #1 screw from each tuner. These simply hold the tuner in place and keep them from rotating when loosening/tightening the barrel nut.
3. Installation is the reverse process, screws in the back, then washers/barrel nuts on the front. Do not apply undue force to either, "finger tight" once they stop turning should be enough.

That said, before you replace anything.... most tuners also have a screw (also a #1) on the knob peg. This provides resistance to the tuner to make it harder to wind (and keep it from unwinding on its own). I would recommend starting with those; tightening them a 1/4 turn (can leave strings on while doing) will add resistance to the winder and prevent them from de-tuning from string tension. Depending how loose those screws are (they could be really loose if the guitar noticeably de-tunes itself), you may also have more room to play with, but if they are bottoming out, do not over tighten them. Let the resistance on the tuner as you wind/unwind tension be your guide (rather than torque on that screw). I added the pic from Sweetwater and put a red square around that screw for reference.

 

Edited September 23 by mettelus

[Xoo]

Thanks - I'll look at the existing tuners when I have time.

[Xoo]

The screw on the existing tuner is pretty tight already (as in, I can't turn it without turning the whole peg).

[Glenn Stanton]

couple of things to check then - if the tuners are tight, it's not likely they're the [main] cause of the guitar going out of tune. i'd first check the nut and bridge to make sure they're smooth and not potentially causing the string tension to change as you play. a rough bridge or nut can cause you to be in tune but as soon as you start playing, the string wrap slips a bit and now it's out of tune.

also, a vibrato / tremolo bridge if it's too loose can make tuning painful.  personally (on my strat) i seldom use the whammy bar, so i insert a block to set my bridge and then tighten the springs. if i'm doing something where i know i'll be using the whammy bar, i'll remove the block and loosen the springs so that the bridge is still mainly stable but can move enough also. the PRS site has some tutorials on adjusting this.

lastly - making sure you stretch your strings sufficiently after changing them will help (a lot) to stablize the tuning.

Edited September 23 by Glenn Stanton

[Chaps]

17 minutes ago, Glenn Stanton said:

lastly - making sure you stretch your strings sufficiently after changing them will help (a lot) to stablize the tuning.

The little things can make a big difference. I'm very meticulous when changing a set of strings. I keep the string snug on the tuner, I hold down the strings with my left hand and pull all the slack out of them with my right hand. I put graphite in my nut slots and 3-in-One oil on the bridge saddles and my TP-6 tailpiece. My Gibson SG stays in tune and is only affected by the temperature and humidity. I've used locking tuners before but the only difference I noticed was it took less time to change strings. People dive-bombing with a whammy bar might have a different experience but I've never had much use for them.

[mettelus]

48 minutes ago, Glenn Stanton said:

a vibrato / tremolo bridge if it's too loose can make tuning painful

I looked PRS Santana SE up and that seems to have a tremolo (not sure if they all do?). I literally have never had to change tuners out on any guitar, so I would focus more on the tremolo and nut as mentioned above. Graphite nuts are "self-lubricating" but for others you can use a pencil in the groove to get graphite on the contact surfaces. Even with bending, if the bridge can move (tremolo) you can start pulling wire over the nut that won't go back due to friction. The number of springs on the tremolo will also make them more rigid, but if this just started happening, that wouldn't be the cause.

On string changes, I actually tune each string two half-steps (full bend) high at first (one at a time), then back them off and tune them properly. The tuning shift from new strings isn't that they actually stretch (a lot of places say this), but that the wraps on the pegs need to "fully take." Tuning them high at the peg takes fewer passes (1-2) for that wrap to take than doing full bends on each string (3-5).

[Glenn Stanton]

using a pipe cleaner with some 800 or higher grit (i use 800 then 1500) polishing compound to pull back and forth through the nut, bridge saddles, and the string ferrules through the body to smooth and polish. i have found on my precision bass, even the badass bridge gets "string dimpled" over time so a quick smoothing works. so while i haven't seen it on my strat it seems possible to get string indentations over time as well (i still polish those every time that i'm also cleaning the neck and polishing frets).

Edited September 23 by Glenn Stanton

[Xoo]

Thanks for all the suggestions.

[mettelus]

On 9/23/2025 at 12:52 PM, Xoo said:

The screw on the existing tuner is pretty tight already (as in, I can't turn it without turning the whole peg).

FWIW, I just did final assembly on the IYV guitar I got yesterday and the G tuner was noticeably looser than the rest (but still didn't unwind itself). To my surprise, tightening that screw also turned the peg with the string on and in tune! I had to hold the peg to tighten it, so a better test might be to see how much force you need to apply to the peg to tighten a tuner (they have a 16:1 torque advantage)... they shouldn't be able to "just move" and should have some resistance to them. If they are lubricated internally (probably why a #1 screw can turn it), that screw may be the only thing applying any real resistance. If a tuner is truly unwinding, the peg would have to rotate to do so (is a worm gear internally), but even at a 16:1 ratio it may not be noticeable visually.

[Starship Krupa]

On 9/26/2025 at 3:46 AM, Xoo said:

Thanks for all the suggestions.

Here's another.

How you tie the string to the post makes a big difference in tuning stability.

I've been using the "luthier's knot" for 40 years, and have never felt the need for locking tuners. I have multiple guitars with Strat-style vibratos, and don't have tuning issues. I do install graphite impregnated nuts on most of my guitars. I'd assume that a high end axe like a PRS would already have a pretty good nut.

 

[Xoo]

The SE isn't that high end (funnily enough, I much prefer how it plays to a high end PRS I tried!).  I do think my knotting may be sub-optimal in some cases, but I don't think it's awful on all the strings!

[DeeringAmps]

These

Grover-Mini-Locking-Rotomatics 406 Series 33Tuners 

Not sure the screw hole lines up exactly. I bought a DGT SE from John Mann and got a set of his MannMade SE USA Locking Tuners
They work fine, but the big screw on the top I find distracting.

t

Back in the day I was not taught the "luthier's knot"; I was taught the first wind goes over the string and, of course, the rest go under.
Never had "issues" once the string is stretched...

[Glenn Stanton]

i only use the "luthier knot" on my acoustic guitars. mainly because the instructions that came with a set of Martin strings that i had bought about 25+ years ago. otherwise, it's simply over once and then under as Tom noted. as long as the tuners are secure to the neck, and the tightening screws are set correctly, i've never seen a working set of tuners be a problem, even if they're cheap tuners. i find it's mainly string stretching, string wear, whammy bridge sticking when using lots of whammy, or the neck isn't rigid enough under tension.

[mettelus]

10 hours ago, Glenn Stanton said:

i've never seen a working set of tuners be a problem, even if they're cheap tuners

+1, even the tuners on my dad's old 1942 Harmony Nobility (fixed bridge) don't unwind. The friction on those is adjusted with the flat head screw on the back of the post. That tuner style is as basic as they come. Again, if a tuner is unwinding the peg has to move.

Another idea that came to mind is if that guitar does have a tremolo, most (all??) tremolos move all strings by the same amount, so if the string tension is not balanced, the higher tension strings will be more likely to bind on the nut. I have used D'Addario Balanced Tension strings for years without issues, and have a floating Kahler tremolo on my main (I almost never use, but I did axle grease the internal hinge pin when I tore it apart 30 years ago). Even with all of the bending I do that doesn't de-tune (the neck is so narrow a full bend puts tension on 4 strings, a standard width neck puts tension on 3); the tremolo just rolls on that hinge pin without issue.

Are the strings that de-tune always the same string(s)?

Edited 21 hours ago by mettelus

[Xoo]

No trem.  Mainly G string, but all barring top B and E aren't great.  G can go noticeably flat after only a few minutes of playing (the others take longer).

The strings are definitely well stretched and played in.  The guitar is about 20-25 years old (eek...doesn't time fly?) and has been getting worse over the last year or so, which is why I thought tuners might be wearing in some way (and if I'm going to replace them, why not get locking ones anyway?).

[Glenn Stanton]

have you had a luthier examine your guitar? making sure there isn't some issue with the neck? a friends instrument i looked at, someone had tightened the truss rod too much and stripped the threads and it was actually shifting slightly when bending strings. another one (different person), they over tightened the truss rod on their bass and it cracked inside the neck. and when i checked, pieces of wood came out after removing the nut on the rod. swapping out the neck with one of mine quickly proved the neck was the issue and further checking it could not be readily repaired...

[Xoo]

I haven't (actually getting to a guitar shop is tricky).  Not that I've tweaked anything on it apart from electronics (and that was done many, many years ago before this problem started).

[Amberwolf]

Has your environment changed?   If humidity / temperature changes are more extreme or more frequent than before the problem began, it could cause issues if they happen long enough or extreme enough, if the wood isn't sealed against them well enough.   A long time ago I had a crappy old acoustic nylon string that used to be my younger sister's, and it held a tune ok, when we were kids in north texas farm country in  a little pink house with a swamp cooler.  After we moved to the desert here, it started to change and had problems, and after a few years it was impossible to tune, you'd start on one string and by the time you got the last one done it had lost the tune on the first one, and no amount of working with it would tune it.   Not like we knew anything about guitars, or how ot store or use htem, etc., so it could probably have been prevented, but....