How to Install and Set Up a Tune-O-Matic Bridge

A Tune-O-Matic bridge is installed as part of a complete mechanical system: bridge body, saddles, posts, thumbwheels, bushings, tailpiece, strings and guitar geometry must work together.

This guide covers post-mounted ABR-1-, Nashville- and metric-style systems as well as KMS ONE and Vintage ONE. The visible bridge shape alone does not establish compatibility; the actual post, thread and bushing geometry must be confirmed first.

Compatibility and Initial Inspection

Before Installation

Before removing the original bridge, document the existing setup.

Record or photograph:

• Bridge orientation
• Saddle positions
• Saddle orientation
• Post height
• Thumbwheel position
• Tailpiece height
• String path
• String gauge
• Tuning
• Current action
• Existing intonation pattern

Take photographs from:

• Above
• The bass side
• The treble side
• The bridge and post area
• The bridge-to-tailpiece string path

These references make it easier to return to the original configuration if necessary.

Confirm Compatibility First

Do not select or install a Tune-O-Matic bridge by appearance or guitar model alone.

Check:

• Post spacing
• Upper post diameter
• Bridge-hole diameter
• Thread standard
• Existing bushings
• Bridge width
• String spacing
• Saddle radius
• Intonation range
• Required installation height

Gibson-style guitars can use several mounting standards that appear similar while remaining mechanically incompatible.

These include:

• Traditional 6-32 ABR-1 mounting
• Gibson Nashville mounting
• Modern ABR-1-style bridges on bushing-mounted posts
• Metric M4 direct mounting
• Metric M5 systems
• Large metric M8 systems
• Converted mounting systems

A bridge that fits approximately is not necessarily compatible.

Required Tools

Useful tools may include:

• Accurate electronic tuner
• Digital caliper
• String-action ruler
• Suitable screwdrivers
• Correct hex keys
• Radius gauges
• String winder
• Soft protective cloth
• Neck support
• Low-tack protective tape
• Manufacturer-supplied tools

Use tools that fit the hardware precisely.

An incorrectly sized tool can damage:

• Screw heads
• Hex sockets
• Threads
• Plating
• Saddle surfaces
• Guitar finish

Protect the Instrument

Place the guitar on a stable, padded surface and support the neck securely.

Protect the area around the bridge and tailpiece from:

• Falling hardware
• Screwdrivers
• String ends
• Metal tools
• Loose bridge components

Nitrocellulose lacquer can be sensitive to pressure, chemicals and some adhesives.

Use only finish-safe protective materials and remove temporary tape promptly.

Reduce String Tension

Reduce string tension before removing the bridge.

When replacing the complete bridge:

1. Detune the strings gradually.
2. Move or remove the strings from the bridge.
3. Hold the bridge so that it cannot fall onto the guitar.
4. Lift the bridge vertically from the posts.

Do not force the bridge sideways.

Resistance may be caused by:

• Bent posts
• Incorrect post spacing
• Corrosion
• Dirt
• Plating buildup
• Misalignment
• Previous modification
• An incompatible bridge

Identify the cause before applying additional force.

Keep Components Organized

Store removed components in a safe container.

These may include:

• Bridge body
• Saddles
• Intonation screws
• Retaining wire or clips
• Thumbwheels
• Posts
• Locking screws
• Washers

Do not assume that all saddles can be returned in any position.

Depending on the bridge, saddles may differ in:

• Height
• Orientation
• Material
• Contact geometry
• String slot
• Radius position

Inspect the Existing Posts

Check the posts for:

• Bending
• Damaged threads
• Corrosion
• Uneven height
• Excessive movement
• Tool damage
• Incorrect alignment

A bent or unstable post can prevent the replacement bridge from seating correctly.

Determine whether the posts:

• Thread directly into the guitar body
• Thread into small metal bushings
• Form part of a Nashville post-and-wheel assembly
• Thread into large metric bushings
• Are conversion posts

The replacement bridge must match the actual upper post geometry.

Inspect the Bushings

Where metal bushings are present, check for:

• Movement inside the guitar body
• Lifting
• Tilting
• Damaged internal threads
• Corrosion
• Cracks around the installation hole
• Evidence of previous repair

Secure and compatible bushings do not need to be removed simply because the bridge is being replaced.

Bushing removal is appropriate only when required by:

• An incompatible mounting system
• A conversion installation
• Damaged threads
• Loose fit
• Incorrect alignment
• Structural damage

Removing pressed-in bushings carries a risk of finish and wood damage and should be performed with the appropriate extraction method.

KMS Conversion Posts

The KMS ONE 2 uses a 6-32 upper mounting and locking system.

Guitars with pressed-in bridge bushings may require KMS Conversion Posts.

The available versions use:

• A 7.2 mm lower press-fit section for suitable small bridge-bushing holes
• A 12.2 mm lower press-fit section for suitable large import-style bridge-bushing holes
• A 6-32 upper thread for the ONE 2 system

Before installing Conversion Posts, verify:

• Existing body-hole diameter
• Hole depth
• Alignment
• Condition of the surrounding wood
• Absence of debris or repair material

Do not select the conversion size by guitar brand alone.

Do not force a Conversion Post into a hole that is too narrow, too shallow, damaged or incorrectly aligned.

Professional installation is recommended when the original bushings are difficult to remove or the body holes require repair.

Test-Fit and Install

Test-Fit the Bridge

Before reinstalling the strings, place the bridge onto the posts carefully.

The bridge should:

• Engage both posts
• Reach the thumbwheels or support surfaces
• Sit without severe rocking
• Move vertically without binding
• Maintain the correct string direction
• Allow access to the adjustment screws

Do not use the bridge body to bend, pull or force posts into alignment.

A locking mechanism must never be used to draw incompatible components together.

Bridge Orientation

There is no universal rule stating that every Tune-O-Matic bridge must have its intonation screws facing the pickups or the tailpiece.

Different bridge designs are intentionally produced in both directions.

The correct orientation depends on:

• Bridge design
• Saddle layout
• Available intonation travel
• Adjustment-screw access
• String clearance
• Manufacturer instructions

Traditional ABR-1 and Nashville bridges are often seen in different orientations, but appearance alone is not a reliable installation guide.

Install the bridge in the orientation specified for the actual product.

Saddle Orientation

The thicker strings normally require more compensation than the thinner strings.

The final saddle pattern will therefore usually place the bass-string contact points farther from the nut than the treble-string contact points.

However, the exact pattern depends on:

• String gauge
• Wound or plain third string
• Tuning
• Scale length
• Action
• Player fretting pressure

Some Tune-O-Matic saddles can be reversed to gain additional intonation travel.

Only reverse a saddle when:

• The bridge design permits it
• The string-contact geometry remains correct
• The slot or V geometry remains correctly oriented
• The retaining system remains functional

Do not reverse saddles merely to create a visually uniform pattern.

Conventional Saddle Slots

Conventional unnotched saddles may require correctly positioned string slots.

Slotting determines:

• String spacing
• Alignment over the fretboard
• Contact point
• String stability
• Final string radius

Slotting is permanent precision work.

It should only be performed after the bridge position and string alignment have been confirmed.

KMS Finished V-Shaped Contacts

KMS V saddles center the string through finished V-shaped geometry rather than through an individually filed conventional slot.

This supports:

• Defined string centering
• Compatibility with a broad range of common string gauges
• Easier gauge changes
• Consistent contact geometry
• Preservation of the intended saddle form

Do not file conventional string slots into the finished KMS V-shaped contacts.

Install the Bridge

Place the bridge vertically onto the posts.

Make sure that:

• Both mounting holes engage correctly.
• The bridge rests on both supporting surfaces.
• The bridge does not bind.
• The correct orientation is maintained.
• Locking screws remain released during initial setup.
• The intonation screws remain accessible.

Begin with the bridge at a conservative height.

Do not start with the strings extremely close to the frets.

Reinstall the Strings

Guide each string through the tailpiece and over the center of its saddle.

Bring the strings gradually toward the intended tuning.

During this process, check that:

• Every string remains centered on its saddle.
• The bridge remains seated.
• The posts remain stable.
• The strings follow a straight and controlled path.
• The outer strings remain suitably positioned over the fretboard.

New strings should be stretched carefully and retuned until they become stable before final intonation.

Use the Intended String Gauge and Tuning

Complete the setup using the string gauge and tuning in which the guitar will normally be played.

Changing either later can alter:

• Neck relief
• Action
• Intonation
• Saddle positions
• String radius
• Playing feel

Intonation set for standard tuning is not automatically ideal for a substantially lower alternate tuning.

Recommended Setup Order

A practical setup sequence is:

1. Install and tune the intended strings.
2. Check neck relief.
3. Set bridge height and action.
4. Check string radius and alignment.
5. Set tailpiece height and string path.
6. Set intonation.
7. Finalize any bridge-locking mechanism.
8. Recheck pickup height.
9. Perform a complete playing test.

These adjustments influence one another.

Intonation should be finalized only after the neck relief, string height and tuning have been established.

Action, Radius and Alignment

Check Neck Relief First

Neck relief influences action and fret clearance throughout the neck.

An unsuitable neck condition can cause:

• Excessive action
• Lower-fret buzzing
• Middle-fret buzzing
• Choking
• Inconsistent feel
• Misleading bridge-height adjustments

The bridge should not be used to compensate for an incorrectly adjusted neck.

Truss-rod adjustment requires care.

When there is uncertainty about the neck condition, resistance at the truss rod or an existing structural issue, the instrument should be assessed by a qualified technician.

Set the Bridge Height

Tune-O-Matic action is adjusted by raising or lowering the bass and treble sides of the bridge.

Depending on the mounting system, adjustment may be made through:

• Separate thumbwheels
• Nashville-style integrated adjustment wheels
• A locking post system

Make small changes and retune after each adjustment.

If a substantial height change is required, reduce string tension first.

Do not grip plated or aged thumbwheels with unsuitable pliers.

Measuring Action

String action is normally measured from:

• The top of the fret
• To the underside of the string

The 12th fret is a common reference position.

Measure the bass and treble sides separately.

There is no single correct action value for every guitar.

The final setting depends on:

• Fret condition
• Neck relief
• Fretboard radius
• String gauge
• Tuning
• Picking force
• Bending requirements
• Player preference

Low action increases the risk of buzzing and choking.

High action increases the required fretting force and can influence fretted pitch.

The Bridge Does Not Need to Look Level

The bass and treble sides of a bridge often require different heights.

This can result from:

• Different string gauges
• Different bass and treble action
• Neck geometry
• Carved guitar top
• Playing preference

The bridge should be adjusted according to the resulting string action, not according to visual symmetry with the guitar body.

Check the String Radius

The final string radius should work with the fretboard radius and intended action.

An unsuitable radius can create:

• Middle strings that sit too high
• Outer strings that sit too high
• Uneven picking feel
• String bends that choke
• Inconsistent action across the string set

Measure the actual strings rather than only the visible saddle tops.

Conventional saddle slots affect the final string height.

KMS V-shaped saddle geometry supports the strings without individually filed conventional slots.

Check String Alignment

Inspect both outer strings along the complete fretboard.

The strings should not run uncomfortably close to either fretboard edge.

Also check:

• Alignment across the pickup area
• Centering on each saddle
• String path from nut to bridge
• Sideways pressure on the saddles
• Overall neck alignment

A bridge can only provide limited correction when the underlying posts, neck or nut are incorrectly positioned.

Tailpiece and String Path

Set the Stop-Tailpiece Height

On guitars with a separate stop tailpiece, its height determines the string path behind the bridge.

Set it so that:

• The strings remain securely seated on the saddles.
• The studs retain adequate thread engagement.
• The tailpiece remains stable.
• The string path does not create unnecessary mechanical interference.
• The resulting feel and response suit the guitar.

Lowering the tailpiece increases the break angle and downward force at the saddles.

Raising it reduces the break angle.

More break angle is not automatically better.

Contact with the Rear Bridge Edge

Inspect the strings between the saddles and tailpiece.

Ideally, the saddle remains the final deliberately defined bridge contact point.

Clearance between the strings and the rear edge of the bridge is therefore generally preferable where the geometry allows it.

However, light rear-edge contact is found on some factory instruments and is not by itself proof of a fault.

It should be assessed when it causes:

• A second pronounced contact point
• String damage
• Unwanted friction
• Finish wear
• Interference with intonation screws
• Excessive load on the bridge
• Audible mechanical problems

Raise the tailpiece when additional clearance is required.

Top-Wrapping

Top-wrapping routes the strings through the stop tailpiece from the pickup side and over its upper surface.

It changes:

• The string path
• Break angle
• Contact with the tailpiece
• Surface wear
• Perceived playing feel

Top-wrapping is an optional setup method, not a requirement for correct Tune-O-Matic installation.

It may mark or wear the upper surface of the tailpiece.

Intonation

Prepare for Intonation

Set intonation only after:

• The intended strings are installed.
• The strings have stabilized.
• The guitar is at the intended tuning.
• Neck relief is correct.
• Action is established.
• Bridge and tailpiece are mechanically secure.

Use an accurate tuner.

Hold the guitar in a normal playing position where practical.

Fretting pressure should remain consistent because excessive pressure can make the measured note artificially sharp.

Intonation Procedure

For each string:

1. Tune the open string accurately.
2. Fret the note at the 12th fret using normal playing pressure.
3. Compare the fretted octave with the correct pitch.
4. Adjust the saddle in a small increment.
5. Retune the open string.
6. Check the fretted 12th-fret note again.
7. Repeat until the best practical result is reached.

The 12th-fret harmonic may also be used as an octave reference, but the fretted note is essential because intonation compensates for the pitch change created when the string is pressed to the fret.

Adjustment Direction

When the fretted 12th-fret note is sharp:

• The vibrating string length is too short.
• Move the saddle away from the nut.

When the fretted 12th-fret note is flat:

• The vibrating string length is too long.
• Move the saddle toward the nut.

Always retune after moving the saddle.

The direction in which an adjustment screw must be turned depends on the bridge orientation and screw design.

Follow the saddle movement rather than relying on a universal clockwise or counterclockwise rule.

Adjust in Small Steps

Do not make large saddle changes without rechecking the pitch.

Small adjustments provide:

• Better control
• Reduced screw load
• More accurate results
• Lower risk of overshooting the correct position

When a saddle is difficult to move, slightly detune the string before adjusting it.

Do not force a resistant intonation screw.

Insufficient Intonation Range

When a saddle reaches the end of its travel before correct intonation is achieved, check the complete setup before modifying the bridge.

Possible causes include:

• Incorrect bridge orientation
• Incorrect saddle orientation
• Wrong string gauge
• Different tuning from the intended setup
• Excessive action
• Incorrect neck relief
• A damaged string
• Incorrect post location
• An incompatible replacement bridge
• Incorrect scale geometry

Some saddles can be reversed to provide additional travel.

Only do this when the bridge and saddle design allow it.

Do Not Diagnose Intonation from Saddle Pattern Alone

A visually unusual saddle arrangement is not automatically incorrect.

The required positions depend on:

• String construction
• String gauge
• Wound or plain third string
• Tuning
• Scale length
• Player pressure
• Action

Judge the result by measured fretted pitch, not by whether the saddles form a familiar visual staircase.

Locking and Final Checks

Finalizing a Locking Bridge

A locking bridge should be seated correctly before its locking mechanism is finalized.

Confirm:

• Correct posts
• Correct thread system
• Full seating
• Stable thumbwheel contact
• Suitable action
• Correct orientation
• Sufficient intonation range
• String alignment

Do not use locking screws to correct:

• Bent posts
• Incorrect spacing
• Binding
• Misalignment
• Incompatible bridge holes

Follow the product-specific tightening sequence and tool instructions.

For the KMS ONE 2, use the correct 6-32 mounting system and follow the current KMS installation guidance for final locking.

Do not overtighten small locking screws.

The mechanism should secure the bridge, not deform it.

Recheck After Locking

After the bridge has been locked, verify:

• Tuning
• Action
• Bridge seating
• Intonation
• String alignment
• Saddle movement
• Mechanical stability

Locking can change how the bridge settles against its supporting components.

Final corrections should be made in small steps.

Recheck Pickup Height

Changing bridge height changes the distance between the strings and pickups.

After the action is finalized, inspect and adjust pickup height as required.

Pickup height influences:

• Output
• String-to-string balance
• Dynamic response
• Tone
• Clearance during hard playing

Pickup adjustment should be performed after the final string height has been established.

Check for Mechanical Noise

Inspect the complete bridge system for:

• Loose intonation screws
• Moving saddles
• Loose retaining wire
• Unstable posts
• Moving bushings
• Uneven thumbwheels
• Loose locking screws
• String contact with screw heads
• String contact with the bridge body
• Tailpiece movement

A rattle should be located mechanically rather than attributed immediately to the bridge material.

String Breakage at the Bridge

Repeated string breakage at the same saddle can indicate:

• A burr
• Damaged contact geometry
• A sharp slot
• Rough coating
• Corrosion
• Excessive local pressure
• An unsuitable string path

Inspect the exact break location.

Do not file or polish a saddle without understanding its geometry and surface system.

Final Playing Test

Test the guitar across the complete fretboard.

Use:

• Open strings
• Chords
• Single notes
• Light picking
• Hard picking
• String bends
• Vibrato
• Palm muting
• Clean amplification
• Distorted sounds where relevant

Evaluate:

• Action
• Buzzing
• Choking
• Tuning
• Intonation
• String alignment
• Attack
• Note separation
• Sustain
• Playing comfort

A setup is complete only when the instrument works in actual playing conditions.

Allow New Strings to Settle

New strings require stretching and repeated tuning.

After the first playing sessions, recheck:

• Tuning
• Intonation
• Action
• Bridge seating
• Locking screws
• Tailpiece height
• String alignment

A stable fixed bridge should not continue to change significantly once the strings and hardware have settled.

Persistent movement should be investigated.

Care and Troubleshooting

Quick Installation and Setup Sequence

1. Confirm the mounting system and bridge compatibility.
2. Document the original configuration.
3. Protect the guitar.
4. Reduce string tension.
5. Remove the original bridge carefully.
6. Inspect posts and bushings.
7. Install the correct Conversion Posts where required.
8. Test-fit the replacement bridge without force.
9. Confirm bridge and saddle orientation.
10. Install the intended strings.
11. Tune gradually and stabilize the strings.
12. Check neck relief.
13. Set bridge height and action.
14. Check string radius and alignment.
15. Set tailpiece height and inspect the string path.
16. Set intonation.
17. Finalize the locking mechanism where applicable.
18. Recheck intonation and action.
19. Recheck pickup height.
20. Perform a complete playing test.

Common Installation Mistakes

Avoid:

• Ordering by guitar model alone
• Assuming every Tune-O-Matic uses the same posts
• Forcing a bridge onto misaligned posts
• Mixing 6-32 and M4 hardware
• Mixing 10-32 and M5 hardware
• Selecting Conversion Posts without measuring
• Pulling secure bushings unnecessarily
• Using locking screws to force alignment
• Installing the bridge according to a universal screw-direction myth
• Filing KMS V-saddles
• Setting action before checking neck relief
• Intonating with unstable strings
• Using inconsistent fretting pressure
• Failing to retune after each saddle adjustment
• Overtightening small screws
• Assuming maximum break angle is always desirable
• Diagnosing compatibility from post spacing alone

When Professional Installation Is Recommended

Professional installation is advisable when:

• Pressed-in bushings must be removed
• Conversion Posts must be installed
• The body holes are damaged
• Posts are bent or misaligned
• The finish is fragile
• Threads are damaged
• Neck relief requires uncertain adjustment
• Frets are uneven
• Compatibility cannot be confirmed
• Permanent body modification would be required
• Correct intonation cannot be reached despite a complete setup check

Stop when installation requires unexplained force.

A bridge upgrade should not risk avoidable damage to the instrument.

Final Verification

Before considering the installation complete, verify:

• Correct compatibility
• Stable mounting hardware
• Bridge orientation
• Saddle geometry
• Neck relief
• String action
• Radius
• Tailpiece height
• Intonation
• Mechanical fit

Retune after the final mechanical adjustment, then recheck action, alignment and intonation in normal playing position.

Related Guides

• Gibson-Style Bridge Mounting Systems →
• ABR-1 vs. Nashville Bridge →
• How to Measure Guitar Bridge Post Spacing →
• How to Set Guitar Bridge Intonation →
• How to Determine Fretboard Radius →
• ONE & Vintage ONE Product Guide →