Setup, done properly
Setup.
The truss rod, the action, the pickups and the strings, and how all four of them pull on each other. Get these right and the guitar you already own will play better than a new one that nobody has touched.
The short version
A setup is not one adjustment. It is four or five adjustments that all affect each other, done in a specific order, because changing any one of them moves the others.
Most guitars that feel bad are not bad guitars. They are guitars nobody has set up. I have handed people back their own instrument after an afternoon of work and had them ask what I replaced. Usually nothing.
Strings first, then relief with the truss rod, then the nut, then action, then pickup height, then intonation last. Every step in that list changes the ones after it. Do them out of order and you will do them twice.
The numbers, in one place
Starting points, not commandments. Your hands and your playing decide the final figures.
| Measurement | Typical figure | Where and how |
|---|---|---|
| Neck relief | 0.008″ to 0.012″ | Capo at 1, fret at the last fret, measure the gap at the 7th or 8th |
| Action, treble side | ~4/64″ (1.6 mm) | Top of the 12th fret to the bottom of the string |
| Action, bass side | ~5/64″ to 6/64″ (2.0 to 2.4 mm) | Same place, low E |
| Nut slot clearance | Barely visible | Fret at 3, look at the gap over fret 1 |
| Humbucker height | ~1/16″ to 1/8″ | Fret the last fret, measure string to pole piece |
| Single coil height | A little more, especially the bass side | Stronger magnets, more pull |
| Truss rod adjustment | 1/8 to 1/4 turn at a time | Then stop and let it settle |
| Total tension, standard 10s | Around 100 lb across six strings | What the neck is holding back all day |
The truss rod, and what it actually does
Start here, because this is the adjustment people misunderstand the most and break the most necks with.
It sets relief, which is the very slight forward bow in the neck. That is its whole job. It exists to balance the pull of the strings, not to raise or lower how high they sit. If you want the strings lower, that happens at the bridge. Using the truss rod to chase action is the single most common way people make a guitar worse while trying to fix it.
What relief is and why you want some
A plucked string does not move in a straight line. It swings in an arc, and that arc is at its widest around the middle of its length. So if the neck were dead flat, the middle of the string would slap into the middle frets every time you dug in.
A tiny amount of forward bow gives that arc somewhere to go. That is relief. You want a small, deliberate amount of it, not a straight neck and not a banana.
Measuring it
Put a capo at the first fret. Hold the string down at the last fret, or where the neck meets the body if you cannot reach comfortably. Now the string is a straight line between two points, which makes it your straightedge.
Look at the gap between the bottom of the string and the top of the fret around the seventh or eighth. That gap is your relief. Measure it with a feeler gauge if you want a number, and you are looking for something in the region of eight to twelve thousandths of an inch.
No feeler gauge? Tap the string down onto the seventh fret. You want a faint click and barely any travel. A big gap and an obvious clunk means too much relief. No movement at all means the neck is flat or bowed backward.
Which way to turn it
| Problem | What you have | What to do |
|---|---|---|
| Buzzing in the middle of the neck, strings sit too close there | Not enough relief, neck too flat or back bowed | Loosen the rod, counterclockwise |
| Action feels high in the middle, notes go sharp when fretted there | Too much relief, neck bowed forward | Tighten the rod, clockwise |
Tightening pulls the neck back toward straight. Loosening lets the strings pull it forward. The rod is fighting about a hundred pounds of string pull, and you are adjusting the balance of that fight.
An eighth to a quarter turn is a real adjustment. Wood does not move instantly, so make the turn, retune, and give it time. On a stubborn neck I will leave it overnight and look again in the morning. People who crank a rod a full turn and then crank it again because nothing happened yet are the reason I see snapped necks.
A rod that feels seized is telling you something. Do not lean on it. Back it off, put a drop of oil on the threads, let it sit, and try again gently. If it still will not move, that is a job for somebody with the tools to fix it when it goes wrong, because a snapped truss rod usually means pulling the fretboard off.
Use the correct wrench, fully seated. Rounding off the nut turns a five minute adjustment into a repair.
For a large adjustment it is worth slackening the strings first, making the move, then bringing it back to pitch. It puts less strain on everything. For a small tweak you can do it at tension.
Two way rods can push the neck back the other way, so they can correct a back bow as well as a forward one. A one way rod can only pull against the strings. If you are building, fit a two way rod. There is no reason not to.
Relief moves with the weather
Wood takes on and gives off moisture as the seasons change, and the neck moves with it. A guitar that was perfect in summer can need a touch of relief taken out in winter. This is normal, it is not a fault, and it is why setup is maintenance rather than a one time event.
Action height
Action is how high the strings sit above the frets, measured at the twelfth fret, from the top of the fret to the bottom of the string.
This is the adjustment with the most personal preference in it, and also the one with the clearest tradeoff.
| Lower action | Higher action | |
|---|---|---|
| Feel | Faster, less effort, easier on the hands | Harder work, more deliberate |
| Buzz | More likely, especially if you dig in | Cleaner, takes a hard attack |
| Volume and sustain | Slightly less, the string has less room to move | More, the string swings freely |
| Suits | A light touch, fast playing | A heavy hand, slide, hard strumming |
A fretboard is curved. The saddles have to follow that same curve, or you end up with the outer strings right and the middle strings either buzzing or sitting too high. Set the two E strings first, then bring the middle four into an arc between them using a radius gauge. A guitar where somebody set each saddle by feel, one string at a time, is instantly recognisable.
Where you actually turn something
- Fender style saddles. Two small grub screws per saddle. Turn both the same amount or the saddle tilts and the string sits crooked in it.
- Tune-o-matic. A thumbwheel at each end of the bridge. You are setting the whole bridge height and the radius is built into the saddle slots, so there is less to fiddle with and less to get wrong.
- Floyd Rose and similar. Height posts at each end. Same idea as a tune-o-matic, and the radius comes from the bridge.
When it buzzes, work out where
Buzz is information. Where it buzzes tells you what is actually wrong, and it is very often not the action.
| Where it buzzes | Most likely cause |
|---|---|
| Open strings only | Nut slot cut too deep |
| Middle of the neck, several frets | Not enough relief |
| Everywhere, all over | Action simply too low for your touch |
| One specific fret, same spot every time | A high or worn fret. No setup fixes this, it needs levelling. |
| Only when you dig in hard | Normal. Either raise it slightly or lighten up. |
That fourth row is the one worth knowing. If a single note buzzes and its neighbours are fine, you can chase the action all day and never solve it, because the problem is a fret sitting proud. There is more on that in the neck and fretwork guide.
Raising or lowering the strings changes how far they travel to reach the fret, which changes how much they stretch, which changes the pitch. So the compensation you set at the saddles is now wrong. Always finish with intonation, never start with it.
Pickup height
This one is free tone, and hardly anybody touches it. Pickups are adjustable for a reason.
The pickup senses the string moving through its magnetic field. Move it closer and the field is stronger where the string is, so you get more output, more low end and a thicker, more compressed sound. Move it away and you get less output, but more clarity, more openness and a cleaner attack.
Setting it
Hold the string down at the last fret, which puts it at its closest to the pickup. Measure from the top of the pole piece to the bottom of the string. Start around a sixteenth to an eighth of an inch and adjust from there by ear.
The neck pickup wants to sit further away than the bridge pickup. The string swings widest around the twelfth fret, which is right over the neck pickup, so it is already getting a much stronger signal. Setting both at the same height gives you a neck pickup that booms and a bridge pickup that sounds weak by comparison.
The magnets in a pickup pull on your steel strings. Get them too close and that pull fights the string's own vibration. You get killed sustain, a strange warbling or beating on sustained notes, and the pitch pulled slightly out. It shows up worst on the low strings and on the neck pickup.
If you have ever had a guitar where the low E goes wobbly and dies quickly and you could not work out why, drop the neck pickup a couple of turns and play it again. Single coils with strong rod magnets are the usual offenders.
Balancing the two
Set the bridge pickup where you want it first, because it is the quieter position and it sets your ceiling. Then bring the neck pickup up or down until switching between them does not change the perceived volume. You are matching loudness by ear, not by ruler.
If your pickup has adjustable pole pieces, you can go further and balance string to string, bringing up a weak string or taming one that jumps out. Follow the curve of the fretboard when you do it.
And trust your ears over any number I can give you. Height numbers are a starting point. The right height is the one where the guitar sounds right to you, plugged into your amp, played the way you play.
String tension, and why it changes everything
This is the part people underestimate. Strings are not just a consumable. The set you choose changes how the instrument feels, how it sounds, and how it is physically set up.
What sets the tension
Three things, and only three. How thick the string is, how long it is, and what pitch you tune it to. Thicker means more tension at the same pitch. Longer scale means more tension at the same pitch. Higher pitch means more tension.
That is why a 24.75″ Gibson scale feels slinkier than a 25.5″ Fender scale with the same gauge strings on it. The string is shorter, so it needs less tension to reach the same note, so it gives more under your fingers. There is more on choosing a scale in the design guide.
What it does to feel and sound
| Heavier strings, more tension | Lighter strings, less tension | |
|---|---|---|
| Feel | Stiffer, more effort, bends fight back | Slinky, easy bends and vibrato |
| Output | More. More mass moving means a bigger signal. | Less |
| Tone | Fuller, more low end, more authority | Brighter and thinner, quicker attack |
| Buzz | Less prone, tolerates a hard hand | More prone, moves further when struck |
| Tuning stability | Better under a heavy attack | Easier to push sharp by pressing hard |
What it does to the guitar itself
This is the bit that catches people. A standard set of tens is pulling somewhere around a hundred pounds against that neck, all day, every day. Change the set and you change that load.
- Relief changes. More tension pulls more forward bow into the neck. So a gauge change means checking the truss rod, every time.
- Intonation changes. Different thickness means different stretch when you fret, so the saddle positions are no longer right.
- A floating tremolo goes out of balance. The springs were set to counter the old tension. Put heavier strings on and the bridge tips forward, put lighter ones on and it sinks back. You have to rebalance the claw.
- Nut slots are cut to a gauge. Go a lot heavier and the strings may not sit properly in the slots, which causes tuning trouble and binding. Go a lot lighter and they rattle in slots that are now too wide.
If you switch gauge and the guitar suddenly plays badly, nothing is broken. The setup is simply no longer matched to what is on it. Pick the gauge you actually want to play, set the guitar up around that, and then stay with it.
Down tuning
Dropping the pitch drops the tension, and everything above happens in reverse. The strings go slack, they buzz, they feel loose, and the intonation moves. The fix is not to fight it with setup alone, it is to go up in gauge to put the tension back where the neck expects it. That is the whole reason players who tune low run heavier sets.
Putting it together
None of these adjustments live alone. Relief affects action. Action affects intonation. String gauge affects relief, intonation and your tremolo. Pickup height affects sustain and pitch. That is why the order matters and why doing one adjustment in isolation so often makes things worse rather than better.
Work through it in order, change one thing at a time, and check what your change did before you touch the next thing. It takes an afternoon the first time and about twenty minutes once you have done it a few times.
And when you are done, go and finish the job properly with the intonation guide, because that is the step that has to come last.