JAM Bridge Installation and Setup: Bushings, Locking, Radius and Intonation

JAM is a fixed, height-adjustable offset bridge whose complete mounting system replaces the traditional freely rocking bridge relationship. On vibrato-equipped instruments, the bridge body stays mechanically fixed while the strings move across the V-Rail® saddle contacts.

Correct installation therefore includes the dedicated JAM bushings, posts, locking nuts, internal height mechanism, lateral alignment and saddle setup as one coordinated system.

Compatibility and JAM Version

Scope of This Guide

This guide covers:

• JAM Classic
• JAM Pro
• JAM Pure
• Selection of the correct JAM bushings
• Removal of the original bridge bushings
• Installation of the JAM mounting system
• Locking the bridge to the mounting posts
• Left-to-right bridge alignment
• Overall bridge-height adjustment
• Individual saddle-height adjustment
• String-radius setup
• Intonation
• Vibrato and return-to-pitch testing
• Routine care
• Troubleshooting

This guide does not cover:

• Drilling new bridge locations
• Correcting an incorrect scale position
• Major body-hole repairs
• Neck-pocket routing
• Vibrato-unit installation
• Fret leveling
• Structural neck repair

When the guitar requires permanent body modification, professional installation is recommended.

JAM Installation Architecture

JAM installation is built around five functional groups:

• Dedicated 9.0 or 9.5 mm KMS bushings
• JAM mounting posts with internal M4 overall-height screws
• Two-hole locking nuts
• Six individually height- and intonation-adjustable V-Rail saddles
• Position-specific compression springs

The locking nuts secure the bridge; the internal M4 screws set overall bridge height. Do not exchange those functions.

The saddle springs use different lengths for different positions and should not be exchanged randomly.

Current JAM Reference Dimensions

The current JAM Bridge specification uses:

• Bridge-body size: 86 × 19 × 10 mm
• Nominal post spacing: 73.0 mm
• Mounting adjustment range: approximately 72.6–73.4 mm
• Overall string spacing: 52.0 mm
• Individual string spacing: 10.4 mm
• Adjustable radius: 7.25"–20"
• Factory preset radius: 12"
• Approximate weight: 62 g
• Bushing outside diameters: 9.0 or 9.5 mm
• Bushing length: 20.5 mm

These values define the present KMS reference.

They do not prove compatibility with every instrument sold under an offset model name.

Compatibility Must Be Measured

Before ordering or installing the JAM Bridge, confirm:

1. Bridge-post center spacing
2. Existing bushing outside diameter
3. Body-hole diameter
4. Body-hole depth
5. Hole alignment
6. Existing bridge height
7. Required action range
8. Overall string spacing
9. Fretboard radius
10. Neck alignment
11. Vibrato configuration
12. String break angle
13. Condition of the surrounding wood and finish

Do not select the bushing size only from:

• Guitar brand
• Country of manufacture
• Model name
• Production year
• Online forum information

Measure the actual guitar.

9.0 mm and 9.5 mm Bushings

The broad practical categories are:

• 9.0 mm for many import-style instruments
• 9.5 mm for many US-style instruments

Both KMS bushing versions are 20.5 mm long. These are practical compatibility categories.

They are not guarantees.

Repairs, production tolerances and replacement thimbles can change the actual body-hole size.

JAM Versions and Installation

Classic, Pro and Pure use the same mounting and adjustment architecture. Classic and Pro are the intended choices for regular vibrato string movement across the saddles; Pure is primarily for fixed or low-movement applications.

The selected surface does not change the bushing, post, locking, height, radius or intonation procedure. Do not file, abrade or reshape the finished V-Rail contact.

Plain or Wound G

The standard saddle orientation is prepared for a plain G. For a wound G, rotate only the G-string saddle body 180 degrees around its longitudinal axis, reinstall the height screws from the upper side, then reset that string’s height, the overall radius relationship and intonation.

Do not reverse the complete bridge body to change G-string compensation.

Left-Handed Configuration

For left-handed use, rotate all six saddle bodies 180 degrees around their longitudinal axes and arrange them in mirrored string positions before completing a new setup. Reversing the complete bridge body alone does not create the correct V-Rail contact geometry.

After either configuration change, re-establish string height, radius, alignment and intonation from the beginning.

Document and Prepare

Before Installation

Document the complete existing setup before removing any component.

Photograph or record:

• Existing bridge orientation
• Bridge height
• Saddle positions
• Saddle radius
• String alignment
• Outer-string distance from the fretboard edges
• Existing bushing position
• Vibrato position
• String gauge
• Tuning
• Neck relief
• Action
• Intonation pattern

Take photographs from:

• Above
• Bass side
• Treble side
• Neck side
• Vibrato side
• Bridge-bushing area

These references make it possible to compare the original geometry and return to the previous configuration where necessary.

Required JAM Tools

JAM uses three principal hex-key sizes.

3 mm Hex Key

Used with the supplied Locking Tool or Pin Tool for:

• Tightening the two-hole locking nuts
• Releasing the two-hole locking nuts

2 mm Hex Key

Used for:

• Internal M4 bridge-height screws
• Intonation adjustment

1.5 mm Hex Key

Used for:

• Individual saddle-height adjustment
• Saddle inclination
• String-radius setup

Use only clean, correctly fitting tools.

A damaged or undersized hex key can damage:

• Brass screws
• Stainless-steel screws
• Hex sockets
• Locking nuts
• Saddle hardware
• Finishes

Additional Useful Tools

Depending on the instrument, useful tools may include:

• Accurate electronic tuner
• Digital caliper
• String-action ruler
• Radius gauges
• String winder
• Suitable bushing-extraction tool
• Protective cloth
• Stable neck support
• Finish-safe low-tack protection
• Small inspection light
• Straightedge
• Fret rocker where necessary

Do not use the bridge or mounting posts as substitute extraction or installation tools.

Protect the Guitar

Place the guitar on a stable padded surface.

Support the neck securely.

Protect the areas around:

• Bridge
• Vibrato
• Pickups
• Bushing holes
• Guitar top
• Rear body

Offset guitars can have thin or aged finishes around the bridge thimbles.

Uncontrolled extraction can lift or chip the finish.

Reduce String Tension

Detune the strings gradually.

Depending on the intended work, the strings can be:

• Moved away from the bridge
• Retained temporarily
• Removed completely

For bushing replacement, complete string removal normally provides safer access.

Prevent the original bridge from falling onto the guitar when the string tension is released.

Remove and Inspect the Original Mounting

Remove the Original Bridge

Lift the original bridge vertically from its thimbles.

Do not force it sideways.

Resistance can result from:

• Corrosion
• Dirt
• Tilted posts
• Bent bridge legs
• Tight thimbles
• Previous modification
• Finish build-up

Identify the cause before applying more force.

The Original Bushings Must Be Evaluated

The defined JAM installation uses the supplied JAM bushings.

Do not assume that the existing bridge thimbles can remain in the guitar merely because the JAM posts appear to enter them.

The complete JAM system is designed around the relationship between:

• JAM bushing
• JAM mounting post
• Internal M4 height screw
• Bridge body
• Two-hole locking nut

Using unrelated thimbles can alter:

• Fit
• Height range
• Stability
• Alignment
• Locking
• Adjustment

Measure Before Removing

Before extracting the original bushings, measure:

• Outside diameter
• Visible flange where present
• Installation depth
• Center spacing
• Height relative to the guitar top

Select the correct 9.0 or 9.5 mm JAM version before removing functioning hardware.

Removing the Original Bushings

Use a controlled extraction method.

Do not:

• Lever a screwdriver against the guitar top
• Pull with unprotected pliers
• Hammer randomly from inside the body
• Use an incompatible bolt that destroys the thread
• Apply heat without understanding the finish
• Twist the bushing through the lacquer

Professional extraction is recommended when:

• The finish is fragile
• The bushings are deeply seated
• Adhesive may have been used
• The holes are damaged
• The guitar is valuable or historically significant
• The installation history is unknown

Inspect the Body Holes

After removal, inspect both holes for:

• Correct diameter
• Correct depth
• Roundness
• Parallel alignment
• Loose wood
• Cracks
• Finish lifting
• Glue residue
• Previous repair
• Oversized openings

The JAM bushings must not be used to conceal structural damage.

Ground Connection

Depending on the guitar, an electrical ground connection may contact:

• A bridge thimble
• The vibrato unit
• Another metal component

When a ground wire is present at a bridge bushing, preserve or re-establish reliable electrical contact according to the guitar’s wiring design.

Do not push the wire aside or damage it during bushing installation.

Electrical work should be performed by a qualified technician where the circuit is uncertain.

Install the JAM Bushings and Posts

Installing the JAM Bushings

Confirm:

• Correct 9.0 or 9.5 mm version
• Clean body holes
• Sufficient depth for the 20.5 mm bushing without bottoming
• Correct alignment
• Protected finish

Install each bushing:

• Straight
• Gradually
• With controlled pressure
• Using a suitable installation tool
• Without striking the visible edge directly

The bushing should sit securely and at the intended depth.

Do not force a 9.5 mm bushing into a 9.0 mm hole.

Do not rely on adhesive to compensate for a severely oversized hole.

Both Bushings Must Remain Parallel

Misaligned bushings can cause:

• Binding posts
• Incorrect bridge spacing
• Uneven height adjustment
• Side loading
• Locking difficulty
• Bridge-body distortion

Check alignment before the bushings are fully seated.

Stop When the Fit Is Incorrect

Do not continue when:

• The bushing enters at an angle.
• The hole is too narrow.
• The hole is too shallow.
• The hole is oversized.
• The finish begins to lift.
• The surrounding wood cracks.
• The two holes do not align with the bridge.
• The scale position is incorrect.

The correct response is repair or professional evaluation, not additional force.

Installing the Mounting Posts

Insert one JAM mounting post into each installed bushing.

Confirm that each post:

• Enters the correct bushing
• Sits straight
• Moves without binding
• Reaches the intended adjustment mechanism
• Remains stable
• Does not damage the bushing

The posts contain the internal M4 bridge-height screws.

Do not substitute unrelated bridge posts.

Position and Lock the Bridge

Place the Bridge onto the Posts

Position the JAM Bridge above the two mounting posts.

Lower it carefully until both mounting openings engage.

The bridge should:

• Sit over both posts without force
• Remain approximately centered
• Rest without severe rocking
• Allow access to both locking nuts
• Remain within its lateral adjustment range
• Leave the saddle and intonation hardware accessible

Do not use the bridge body to bend the posts into alignment.

Install the Two-Hole Locking Nuts

Thread one two-hole nut onto each mounting post.

Initially tighten them only enough to retain the bridge loosely.

Do not fully lock the bridge yet.

The bridge must first be checked for:

• Height
• Left-to-right position
• String alignment
• Post fit
• Action range

Using the Locking Tool

Place the supplied Pin Tool or Locking Tool into the two holes of the locking nut.

Operate it with the 3 mm hex key.

Clockwise

Tightens the locking nut and secures the bridge to the mounting post.

Counterclockwise

Releases the locking nut.

Use controlled hand force.

Do not use pliers on the locking nut.

Do not use an improvised two-pin tool that damages the holes or visible surface.

The Locking Nuts Do Not Set Bridge Height

The two-hole nuts perform the locking function.

They do not replace the internal bridge-height screws.

Do not attempt to raise the bridge by leaving the nuts partly unsupported or by using them as conventional thumbwheels.

The correct division of functions is:

Internal M4 Height Screw

Controls vertical bridge position.

Two-Hole Nut

Locks the bridge body to the mounting post.

Initial Left-to-Right Alignment

The current JAM body provides a limited mounting-adjustment range around its nominal 73.0 mm post spacing.

This also allows the overall string path to be aligned within the designed range.

With the bridge still lightly secured:

1. Install or position the two outer strings.
2. Bring them to light tension.
3. Inspect their relationship with both fretboard edges.
4. Check the bridge-pickup alignment.
5. Shift the bridge body carefully where required.
6. Confirm that neither mounting opening is forced against a post.
7. Retain the position lightly with the locking nuts.

Do not use lateral adjustment to conceal:

• A misaligned neck
• Incorrectly positioned bushings
• Incorrect nut spacing
• Severe body-routing error

The adjustment is for precise alignment, not structural correction.

Height, Alignment and Radius

Setting the Initial Bridge Height

The JAM mounting posts contain internal M4 bridge-height screws.

These screws are reached through the center of the post.

Use the 2 mm hex key.

Clockwise

Raises that side of the bridge.

Counterclockwise

Lowers that side of the bridge.

This direction is defined by the JAM mechanism and differs from some conventional bridge systems.

Release the Locking Nuts Before Height Adjustment

Before changing the bridge height:

1. Loosen both two-hole locking nuts slightly.
2. Confirm that the bridge can move vertically.
3. Reduce string tension when raising the bridge substantially.
4. Insert the 2 mm hex key into the internal height screw.
5. Make a small adjustment.
6. Repeat on the other side where required.
7. Retighten the locking nuts only after the height is established.

This is essential.

Attempting to change the height while the bridge is tightly locked can place opposing forces into:

• Bridge body
• Mounting posts
• Locking nuts
• Bushings
• Internal height screws

Do Not Raise the Bridge Under Full String Tension

When the bridge must be raised, reduce string tension first.

Raising the loaded bridge increases stress on the height mechanism and locking assembly.

Small final checks can be made carefully, but substantial upward adjustment should not be carried out against full string tension.

Bass and Treble Height

The two sides can be set independently.

The bass side may require more height because of:

• Larger string diameter
• Wider vibration amplitude
• Playing force
• Neck geometry

The bridge does not need to appear visually horizontal relative to the body.

It must produce the intended string action.

Locking the Initial Height

After the initial height is established:

1. Confirm that both posts remain straight.
2. Confirm that the bridge rests stably.
3. Check left-to-right alignment.
4. Tighten both two-hole nuts with the Pin Tool.
5. Use controlled force.
6. Recheck the height.

The nuts should secure the bridge positively without deforming the assembly.

The JAM Bridge Does Not Rock

Once correctly locked, the bridge body should not move back and forth in the bushings during vibrato use.

This is intentional.

The fixed body supports:

• Defined intonation
• Stable radius
• Reduced bridge drift
• Reduced mechanical movement
• Controlled string contact

For Classic and Pro, the strings glide across the engineered V-Rail saddle surfaces during offset-vibrato movement.

Check the Complete Mechanical Assembly

Before proceeding, confirm:

• Both bushings are secure.
• Both posts are straight.
• Both internal height screws operate.
• Both locking nuts engage correctly.
• The bridge remains centered.
• No component binds.
• No part contacts the guitar top.
• The intonation screws remain accessible.
• The saddle-height screws remain accessible.

Install the Intended String Set

Complete the setup with the exact strings and tuning intended for normal playing.

Confirm:

• String gauges
• Plain or wound third string
• Tuning
• Scale length
• Vibrato use
• Player preference

Changing the string set later can alter:

• Neck relief
• Action
• Saddle radius
• Intonation
• Break angle
• Vibrato feel
• Return to pitch

Tune Gradually

Bring the strings toward pitch in several stages.

During tuning, check:

• String centering
• Bridge stability
• Locking-nut security
• Post position
• Bushing stability
• Outer-string alignment
• Vibrato behavior

New strings should be stretched before final setup.

Establish the String Witness Points

After bringing fresh strings toward pitch, press each string gently downward:

• Immediately in front of the bridge saddle
• Immediately behind the bridge saddle
• At the nut where appropriate

This helps the string follow a defined path across the contact points.

Do not create sharp bends or damage the string.

Retune afterward.

Check Neck Relief First

Neck relief influences the complete action profile.

An unsuitable neck condition can cause:

• Excessive action
• Lower-fret buzz
• Middle-fret buzz
• Choking
• Uneven feel
• Misleading bridge adjustments

Do not use JAM saddle height or bridge height to compensate for an incorrectly adjusted neck.

The practical sequence is:

1. Install the intended strings.
2. Tune the guitar.
3. Check neck relief.
4. Correct the neck where necessary.
5. Establish overall bridge height.
6. Establish the individual saddle radius.

Set the Overall Bridge Height

Use the internal bridge-height screws to establish the broad bass and treble action.

Before adjustment:

• Loosen the two-hole locking nuts.
• Reduce string tension when raising the bridge.
• Use the 2 mm hex key.
• Make small changes.

After adjustment:

• Retune.
• Measure the action.
• Check bridge alignment.
• Retighten the locking nuts.

Measure the Action

Action is normally measured from:

• Top of the fret
• To underside of the string

The 12th fret is a common reference.

Measure at least:

• Lowest string
• Highest string

The final values depend on:

• Neck relief
• Fret condition
• String gauge
• Fretboard radius
• Playing force
• Bending
• Tuning
• Personal preference

Set the Broad Bass-to-Treble Relationship First

Use the two bridge-height mechanisms to establish:

• General bass-side height
• General treble-side height

Do not attempt to create the complete radius only through the two mounting posts.

The individual saddle screws provide the detailed string-to-string adjustment.

Individual JAM Saddle Height

Each V-Rail saddle has two small height screws.

Use the 1.5 mm hex key.

Clockwise

Raises the saddle at that screw.

Counterclockwise

Lowers the saddle at that screw.

Because each saddle uses two screws, its:

• Height
• Side-to-side inclination
• Contact with the bridge body

can be controlled individually.

Keep Both Saddle Screws Supported

Both saddle-height screws should maintain defined support.

Avoid a setup in which:

• One screw carries the complete load unnecessarily.
• One screw remains loose.
• The saddle rocks.
• The saddle is severely tilted without reason.
• A screw projects excessively.
• The string contacts a height screw.

A small controlled inclination can be used to create the required radius and bass-to-treble relationship.

Mechanical stability remains essential.

Factory Radius

The JAM Bridge is supplied with a nominal 12" preset radius.

This is a starting point.

It is not automatically correct for every guitar.

Adjustable Radius Range

The JAM saddle architecture supports a broad practical range from:

• 7.25"
• Through 12"
• Up to 20"

This allows the bridge to work with many:

• Vintage-radius necks
• Modern-radius necks
• Flatter performance necks
• Compound-radius fingerboards

Measure the Strings, Not the Saddle Tops

The playing radius is formed by the actual string surfaces.

It depends on:

• Saddle height
• Saddle inclination
• String diameter
• Bass-to-treble action
• Fretboard geometry

Use a radius gauge beneath the strings where practical.

Do not judge the radius only by looking at the saddle bodies.

Fretboard Radius and Bridge Radius

A constant-radius fretboard commonly uses a related string-radius curvature at the bridge, adjusted for the intended action.

A compound-radius neck normally requires a flatter radius at the bridge than at the nut.

The bridge should follow the projected fingerboard geometry.

Do not automatically copy the nut radius.

Practical Radius Procedure

1. Establish correct neck relief.
2. Set the broad bass and treble action.
3. Tune the guitar.
4. Measure the outer-string action.
5. Place the correct radius gauge beneath the strings.
6. Adjust each middle saddle using the 1.5 mm key.
7. Keep both height screws supported.
8. Retune.
9. Recheck every string.
10. Test bends across the complete neck.

Do Not File the V-Rail Saddles

The V-Rail contact is a finished precision geometry.

Do not:

• Cut conventional slots
• Deepen the contact
• Widen the groove
• Round the rail
• Polish the contact aggressively
• Abrade Classic or Pro coatings

String alignment and radius are adjusted mechanically.

They are not created by filing permanent slots.

Break Angle

The string must maintain secure contact with the V-Rail saddle.

The available pressure depends on:

• Bridge height
• Neck angle
• Vibrato position
• String gauge
• Guitar geometry

More break angle is not automatically better.

Too little can reduce secure contact.

Excessive break angle can increase:

• Saddle pressure
• Friction
• String wear
• Stiffness
• Downward load

The JAM height should be selected as part of the complete neck-and-vibrato geometry.

Neck Angle and Shimming

Some offset guitars require an appropriate neck angle to achieve:

• Useful bridge height
• Suitable break angle
• Correct action
• Secure string contact

The bridge should not be lowered beyond its useful range to compensate for an unsuitable neck angle.

Neck-pocket shimming is a guitar-setup operation and should be performed correctly with an appropriate full-contact or purpose-designed shim where required.

Prepare for Intonation

Set intonation only after:

• The intended strings are installed.
• The strings have stabilized.
• The guitar is tuned correctly.
• Neck relief is correct.
• Overall bridge height is established.
• Individual saddle height is established.
• String radius is correct.
• The bridge is locked securely.
• The vibrato system is operating normally.

Changing action or radius afterward can affect the result.

Intonation

Fresh Strings

Fresh strings are strongly recommended for final intonation.

Old, damaged or contaminated strings can produce:

• Unstable pitch
• False harmonics
• Irregular compensation
• String-to-string inconsistency

Stretch the strings carefully and retune several times.

Intonation Reference

For each string:

1. Tune the open string accurately.
2. Play the 12th-fret harmonic as an octave reference.
3. Fret the note at the 12th fret using normal pressure.
4. Compare the fretted note with the intended octave.
5. Adjust the saddle.
6. Retune the open string.
7. Repeat the test.

The fretted note is essential because compensation addresses the pitch change produced when the string is pressed to the fret.

Intonation Adjustment Tool

Use the 2 mm hex key in the JAM intonation screw.

The adjustment direction is:

Counterclockwise

Moves the saddle forward, toward the neck.

Clockwise

Moves the saddle backward, away from the neck.

Always observe the actual saddle movement.

Do not rely only on a generic clockwise rule from another bridge design.

Fretted Note Is Flat

When the fretted 12th-fret note is too low:

• The vibrating string length is too long.
• Move the saddle forward.
• Move it toward the neck.
• Turn the JAM intonation screw counterclockwise.

Retune and check again.

Fretted Note Is Sharp

When the fretted 12th-fret note is too high:

• The vibrating string length is too short.
• Move the saddle backward.
• Move it away from the neck.
• Turn the JAM intonation screw clockwise.

Retune and check again.

Use Small Adjustments

Make small changes.

A useful cycle is:

1. Measure.
2. Adjust.
3. Retune.
4. Measure again.

Do not attempt to calculate the complete movement from one pitch reading.

Reduce String Load When Necessary

When an intonation screw is difficult to turn:

• Reduce string tension slightly.
• Confirm that the saddle is not binding.
• Check the spring.
• Check the screw path.
• Check for contamination.
• Confirm that the screw has not reached its limit.

Do not force the screw.

Three Compression-Spring Lengths

The original JAM assembly uses three compression-spring lengths.

These help maintain appropriate pressure through different saddle-position ranges.

During service:

• Keep the spring positions documented.
• Do not assume all six springs are identical.
• Do not exchange them randomly.
• Do not shorten a spring.
• Do not stretch a spring.
• Replace damaged springs with the correct KMS component.

Current production uses revised industrial spring specifications.

The correct replacement must match the production version.

Anti-Rattle Intonation System

Current JAM production uses revised intonation hardware with a clear anti-rattle polymer element.

Its purpose is to support:

• Stable screw positioning
• Smooth adjustment
• Reduced unwanted movement
• Reduced mechanical noise

Do not remove, abrade or lubricate the polymer component without KMS guidance.

The exact screw material can vary by JAM version or production revision.

Use the correct product-specific replacement part.

Do Not Set Intonation by Appearance

A familiar staggered saddle pattern is common.

It is not the objective.

Final saddle positions depend on:

• String gauge
• Core construction
• Winding
• Plain or wound third string
• Tuning
• Scale
• Action
• Fretting pressure

Judge the setup by measured pitch.

Insufficient Intonation Range

When a saddle reaches the end of its travel, check:

• String condition
• String gauge
• Tuning
• Action
• Neck relief
• Bridge position
• Scale geometry
• Saddle assembly
• Spring position
• Intonation screw condition

Do not modify the bridge body or saddle until the complete setup has been evaluated.

Final Bridge Lock Check

After intonation:

1. Confirm that both two-hole nuts are secure.
2. Confirm that the bridge remains at the intended height.
3. Check left-to-right alignment.
4. Check every saddle-height screw.
5. Check every intonation screw.
6. Retune the guitar.
7. Recheck intonation.
8. Perform a complete playing test.

Vibrato Validation

Vibrato Operation

JAM is a fixed bridge.

During offset-vibrato use, the strings move over the saddle contact while the bridge body remains locked.

Correct operation therefore depends on:

• Suitable JAM version
• Clean saddle contact
• Correct string pressure
• Smooth nut and string-tree contact
• Correct vibrato setup
• Stable tuning machines
• Secure bridge locking
• Stable string installation

JAM Classic and Vibrato

The hardened electroless-nickel V-Rail surface is intended to provide:

• Smooth string movement
• Wear resistance
• Reliable return
• Traditional metallic appearance

JAM Pro and Vibrato

The DLC-over-nickel V-Rail system provides the most performance-focused surface system.

It is particularly suitable for:

• Frequent vibrato use
• Stronger vibrato movement
• Touring
• High wear
• Sweat-intensive use
• Humid conditions

JAM Pure

Pure provides uncoated brass contact.

Its current KMS positioning favors:

• Fixed applications
• Fixed setups with little string movement across the saddles
• Instruments where extensive string travel across the saddles is not central

The correct version should be selected before installation.

A surface cannot be changed into another JAM version through polishing or lubrication.

Return-to-Pitch Test

After complete setup:

1. Tune the guitar accurately.
2. Use light vibrato.
3. Release the arm naturally.
4. Check tuning.
5. Repeat several times.
6. Increase movement gradually.
7. Check every string individually.

Do not begin with extreme vibrato travel.

When All Strings Shift Together

Inspect:

• Vibrato unit
• Bridge locking
• Mounting posts
• Bushings
• Overall bridge movement
• Nut
• String trees
• Tuning machines

When One String Shifts Differently

Inspect:

• V-Rail contact
• Nut slot
• String tree
• Tuning-machine winding
• String damage
• Saddle contamination
• Individual intonation hardware

A single-string problem is less likely to originate from both JAM mounting posts.

Care and Troubleshooting

Routine Cleaning

After playing:

• Wipe away sweat.
• Use a soft clean cloth.
• Remove dust from recesses.
• Keep screw sockets clean.
• Keep the V-Rail contact free from deposits.
• Dry the bridge before storing the guitar.

Do not allow liquid to collect around:

• Saddle-height screws
• Intonation screws
• Compression springs
• Locking nuts
• Mounting posts
• Bushings
• Internal bridge-height screws

JAM Classic Care

The hardened electroless-nickel saddle surface is functional.

Avoid:

• Abrasive metal polish
• Steel wool
• Scouring pads
• Aggressive acids
• Hard mechanical polishing
• Filing the V-Rail

Normal discoloration should be distinguished from actual surface damage.

JAM Pro Care

DLC provides a hard, low-friction functional surface.

It can still be damaged by:

• Incorrect tools
• Sharp impact
• Abrasive compounds
• Filing
• Edge chipping
• Uncontrolled polishing

Clean gently.

Do not attempt to recreate the DLC surface after local damage.

JAM Pure Care

Uncoated brass can develop:

• Darkening
• Warm patina
• Polished contact areas
• Natural color variation

This is not automatically a defect.

Remove harmful deposits while preserving the intended brass surface.

Do not apply aggressive brass polish to the V-Rail contact without KMS guidance.

V-Rail Care

Do not:

• File the rail
• Cut a conventional saddle slot
• Use abrasive cord
• Scrape the contact
• Apply unidentified lubricant
• Round the geometry
• Recoat the saddle locally

The V-Rail is a finished precision contact.

Locking-Nut Care

Periodically check that both two-hole nuts remain:

• Secure
• Undamaged
• Correctly seated
• Free from contamination

Do not perform routine overtightening.

Use the Pin Tool only when adjustment is required.

Height-Mechanism Care

The internal M4 bridge-height screws should remain:

• Clean
• Adjustable
• Correctly seated
• Free from excessive force

Always loosen the top locking nuts before height adjustment.

Do not introduce unapproved lubricant into the post without KMS guidance.

Saddle-Height Screw Care

Check that:

• Both screws support each saddle.
• No screw is loose.
• No saddle rocks.
• The radius remains correct.
• No screw contacts the string.

A loose height screw can create mechanical noise.

Do not solve the problem with thread-locking compound unless explicitly approved.

Intonation Hardware Care

Inspect:

• Intonation screw
• Compression spring
• Anti-rattle polymer
• Saddle movement
• Screw socket

Do not randomly exchange different spring lengths.

Do not force a screw against the end of its range.

Bushings

Inspect the guitar around the bushings for:

• Movement
• Lifting
• Cracked finish
• Tilting
• Gap formation
• Loss of ground contact where applicable

A moving bushing is a body-mounting problem.

Tightening the locking nut more strongly is not a repair.

Common Troubleshooting

Bridge Rocks or Moves

Check:

• Two-hole locking nuts
• Mounting posts
• Bushings
• Bushing fit
• Bridge-body seating
• Internal height screws
• Body-hole condition

The JAM body should remain fixed when correctly installed.

Bridge Height Cannot Be Adjusted

Check:

• Locking nuts have been loosened
• Correct 2 mm tool
• Internal M4 screw condition
• String tension
• Contamination
• End of adjustment range
• Post and bushing alignment

Do not force the internal screw.

Bridge Height Changes After Locking

Check:

• Both locking nuts
• Internal screw seating
• Post stability
• Bushing movement
• Unequal support
• Excessive locking force

One Saddle Rocks

Check:

• Both 1.5 mm height screws
• Saddle inclination
• Screw seating
• Debris
• Screw damage

Both screws should provide stable support.

Radius Feels Uneven

Check:

• Neck relief
• Overall bridge height
• Actual string radius
• Individual saddle heights
• String gauges
• Compound-radius geometry

Do not evaluate only the visible saddle tops.

String Leaves the Saddle

Check:

• Break angle
• Neck angle
• Bridge height
• String alignment
• V-Rail damage
• Playing force
• Vibrato setup

Do not deepen the V-Rail as the first response.

Intonation Screw Rattles

Check:

• Correct spring
• Spring length
• Anti-rattle polymer
• Screw position
• Saddle movement
• End of adjustment range
• Production-version compatibility

String Does Not Return to Pitch

Check:

• JAM version
• V-Rail cleanliness
• Nut slots
• String trees
• Tuning machines
• Vibrato unit
• String installation
• Bridge locking
• String witness points

Do not assume that every tuning problem originates at the bridge.

String Breaks at the Bridge

Inspect:

• Exact break location
• V-Rail surface
• Contamination
• Coating damage
• Excessive break angle
• String quality
• Burrs or impact damage

Do not file the saddle before identifying the cause.

Correct Intonation Cannot Be Reached

Check:

• String condition
• Tuning
• Action
• Neck relief
• Saddle travel
• Bridge scale position
• Spring arrangement
• Screw condition
• Fretting pressure

Quick Installation and Setup Sequence

1. Confirm that JAM is suitable for the instrument.
2. Measure post spacing and existing body holes.
3. Select 9.0 or 9.5 mm JAM bushings.
4. Select Classic, Pro or Pure for the intended application.
5. Document the original setup.
6. Protect the guitar.
7. Remove the strings or reduce tension safely.
8. Remove the original bridge.
9. Extract the original bushings correctly.
10. Inspect body holes and any ground connection.
11. Install the JAM bushings straight and securely.
12. Insert the JAM mounting posts.
13. Place the bridge onto the posts.
14. Install both two-hole nuts loosely.
15. Align the overall string position.
16. Loosen the nuts before setting bridge height.
17. Set height with the internal 2 mm M4 screws.
18. Tighten the locking nuts with the Pin Tool and 3 mm key.
19. Install and stabilize the intended strings.
20. Check neck relief.
21. Set overall bridge height.
22. Set individual saddle height with the 1.5 mm key.
23. Verify the actual string radius.
24. Establish suitable break angle.
25. Stretch and stabilize the strings.
26. Set intonation using the 2 mm key.
27. Retune after every saddle movement.
28. Recheck bridge locking.
29. Test vibrato return.
30. Perform a complete playing test.

Common Installation Mistakes

Avoid:

• Selecting bushings by guitar brand alone
• Leaving unrelated original thimbles in place
• Forcing the wrong bushing size
• Damaging the guitar finish during extraction
• Installing tilted bushings
• Using the bridge body to align posts
• Treating the locking nuts as height wheels
• Adjusting height while the nuts remain locked
• Raising the bridge under full string tension
• Using the wrong hex key
• Filing V-Rail saddles
• Randomly exchanging spring lengths
• Setting radius from saddle appearance alone
• Intonating before action and radius are established
• Forcing an intonation screw
• Applying thread-locking compound
• Using abrasive polish on Classic or Pro
• Selecting Pure for extensive string movement without considering its intended application
• Tightening the bridge lock to compensate for a loose bushing
• Ignoring the nut, string trees or vibrato during tuning diagnosis

When Professional Installation Is Recommended

Professional installation is advisable when:

• Original bushings are difficult to remove.
• The finish is fragile.
• Body holes are damaged.
• The holes are oversized.
• Bushings are misaligned.
• A ground wire requires repair.
• The neck angle is unsuitable.
• A neck shim is required.
• Correct action cannot be achieved.
• Frets are uneven.
• Scale position is incorrect.
• Permanent routing or drilling is required.
• Vibrato return remains unstable after a complete setup.
• Any adjustment requires unexplained force.

The JAM Setup Principle

The JAM Bridge separates its functions clearly.

Bushings and Posts

Create the body connection.

Internal M4 Screws

Set the overall bridge height.

Two-Hole Nuts

Lock the bridge into position.

Individual Saddle Screws

Create action and radius.

Intonation Screws

Set the vibrating string length.

V-Rail Surfaces

Control the immediate string contact.

Each adjustment must be made through the component intended for that function.

Final Verification

Before considering the installation complete, verify:

• Correct bushings
• Stable posts
• Internal height adjustment
• Positive bridge locking
• Individual saddle height
• String radius
• V-Rail contact
• Intonation
• Vibrato
• Nut and tuning hardware

After the bridge is fully locked, retune and repeat the vibrato and return-to-pitch check before finalizing the setup.

Related Guides

• How to Determine Fretboard Radius →
• How to Set Guitar Bridge Intonation →
• When Should Guitar Bridge Bushings Be Replaced? →
• Choosing Guitar Saddle Materials →
• Decorative Finishes vs. Functional Coatings →