JAM is a fixed, non-rocking offset bridge for Jaguar-, Jazzmaster- and related offset-style guitars with compatible mounting geometry. Its CNC-machined stainless-steel bridge body locks into a defined position while six individually adjustable brass V-Rail® saddles control string height, radius, intonation and the immediate string contact.
The family uses one bridge architecture with three different surface systems: JAM Classic, JAM Pro and JAM Pure.
In Brief
- Fixed, non-rocking bridge body with dedicated KMS posts, bushings and positive locking.
- Six individually intonated brass V-Rail saddles with adjustable 7.25–20 inch radius.
- JAM Classic uses hardened electroless nickel; JAM Pro adds DLC; JAM Pure uses direct uncoated brass contact.
- Classic and Pro are the main choices for active offset-vibrato use; Pure is intended for applications with little string movement across the saddles.
- 73.0 mm nominal post spacing, 72.6–73.4 mm mounting range and 52 mm overall string spacing.
Product Overview
Feature | JAM Bridge |
Architecture | Fixed, non-rocking offset bridge |
Bridge body | CNC-machined stainless steel |
Saddles | Six individually adjustable brass V-Rail saddles |
Radius | Adjustable 7.25–20 in · 12 in factory preset |
Mounting | 73.0 mm nominal · 72.6–73.4 mm adjustment range |
Versions | Classic · Pro · Pure |
JAM replaces the traditional rocking-bridge principle with a fixed body and controlled moving-string contact. The bridge remains highly adjustable; only unintended bridge movement is removed.
How the JAM Architecture Works
Fixed Bridge, Moving Strings
On a vibrato-equipped offset guitar, string tension changes as the vibrato moves. JAM keeps the bridge body fixed in its selected position instead of relying on the bridge to rock inside loose thimbles.
Classic and Pro use engineered low-friction V-Rail surfaces so the strings can move across the saddles while the bridge remains mechanically stable.
V-Rail String Contact
Each string runs over its own finished V-Rail contact. The geometry centers the string, provides a defined speaking point and supports common guitar-string gauges without conventional saddle-slot filing.
The V-Rail is finished geometry. It should not be filed, widened or polished to alter string position or gauge fit; height, radius and intonation are set mechanically.
Adjustment Without Bridge Movement
JAM separates the main setup functions:
- Internal M4 screws set overall bass- and treble-side bridge height.
- Two-hole locking nuts secure the bridge to the posts.
- Two M3 screws per saddle set individual string height and radius.
- Individual intonation screws set the speaking length of all six strings.
- Slotted bridge mounts provide limited overall left-to-right alignment.
This gives the bridge a variable radius from approximately 7.25 to 20 inches while keeping the body positively located.
Choosing JAM Classic, Pro or Pure
The three versions are not quality levels. Choose them by string movement, surface requirement and desired response.
Version | String-contact surface | Best starting point | KMS response direction |
JAM Classic | Hardened electroless nickel over brass | Regular offset-vibrato use · all-round application | Rich · lively · balanced · harmonically separated |
JAM Pro | DLC over hardened electroless nickel and brass | Heavy vibrato use · touring · high wear · sweat and humidity | Focused · controlled · firm · clearly separated |
JAM Pure | Direct uncoated brass | Fixed or blocked applications with little string movement | Open · immediate · lively · dynamically broad |
Classic
Classic is the broad all-round choice for a conventional offset vibrato. The hardened electroless-nickel surface combines smooth moving-string contact, wear resistance and a traditional metallic appearance.
Pro
Pro adds a DLC outer layer over the hardened nickel support layer. It is the performance-led choice when vibrato use, surface durability and demanding stage conditions are central. It is not simply a black Classic.
Pure
Pure places the string directly on uncoated brass. Choose it when direct brass contact is the priority and the strings do not repeatedly glide across the saddles. For an actively used offset vibrato, Classic or Pro is the more appropriate starting point.
Materials, Tone & Surface Function
The JAM architecture uses different materials for different mechanical roles. The stainless-steel bridge base provides the structural foundation; the V-Rail saddle bodies are brass in all three versions. Classic and Pro then modify the immediate string interface with functional hard surfaces.
Material and surface therefore work together: the saddle body establishes the underlying material direction, while the contact surface changes friction, wear behavior and the immediate response.
The bridge body is available polished or brushed. This changes appearance, not the selected Classic, Pro or Pure saddle system. Optional CRYO treatment is a separate material-conditioning choice and does not alter the geometry, bushing size or setup method.
Compatibility and Configuration
Compatibility is more than post spacing. Before ordering, confirm the complete relationship between body holes, bushings, bridge height, string spacing and neck alignment.
JAM uses:
- 73.0 mm nominal post spacing with approximately 72.6–73.4 mm mounting range.
- 52.0 mm overall E-to-e string spacing and 10.4 mm individual spacing.
- Dedicated 9.0 mm or 9.5 mm KMS bushings, both 20.5 mm long; a Dual Pack is available where the body-hole class is uncertain.
- Approximately 7.25–20 inch radius adjustment.
The original offset thimbles are replaced by the supplied KMS bushings. A matching post-spacing measurement alone does not prove compatibility if the body-hole diameter, depth, bridge height or string path are unsuitable.
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 and reset height, radius and intonation.
Left-Handed Configuration
For left-handed use, rotate all six saddle bodies 180 degrees and arrange them in mirrored string positions before completing a new setup. Reversing the complete bridge body alone does not create the correct contact geometry.
Technical Specifications
Feature | Specification |
Architecture | Fixed, non-rocking offset bridge |
Bridge-base material | CNC-machined stainless steel |
Saddle material | CNC-machined brass |
Body size | 86 × 19 × 10 mm |
Reference weight | Approximately 62 g |
Nominal post spacing | 73.0 mm |
Mounting range | 72.6–73.4 mm |
Overall / individual string spacing | 52.0 mm / 10.4 mm |
Radius range | 7.25–20 in · 12 in factory preset |
KMS bushings | 9.0 or 9.5 mm OD · 20.5 mm length |
Saddle-height screws | M3 brass · two per saddle |
Bridge-height screws | M4 brass · top access through hollow posts |
Mounting assembly | Precision-turned stainless steel · separate height adjustment and locking |
Intonation screws | Classic/Pure: stainless steel · Pro: brass · clear anti-rattle polymer |
Body finish | Polished or brushed stainless steel |
Optional treatment | CRYO |
The position-matched saddle springs use different lengths and should remain assigned to their intended positions. The clear anti-rattle polymer is designed to reduce unwanted intonation-screw movement while preserving smooth adjustment.
Installation and Setup
JAM installation replaces the original offset thimbles with the dedicated KMS bushings, then separates bridge height, locking, individual saddle height/radius and intonation into their respective adjustments.
For the complete installation and setup procedure, see:
JAM Bridge Installation and Setup →
FAQ
Is JAM a traditional rocking offset bridge?
No. JAM is deliberately fixed and non-rocking. On Classic and Pro, the strings move across the V-Rail contacts while the bridge body remains locked in position.
Is JAM Pro automatically the best version?
No. Pro is the most wear- and performance-focused surface for intensive moving-string use. Classic is already the dedicated all-round vibrato version, while Pure serves a different direct-brass application.
Should I choose JAM Pure for an actively used offset vibrato?
Usually not. Pure has no dedicated hardened low-friction contact surface. For regular string movement across the saddles, Classic or Pro is the better starting point.
Do the V-Rails need to be filed for my string gauge?
No. They are finished precision contacts. Filing changes string height, radius, friction and surface function.
Does JAM have a fixed 12-inch radius?
No. Twelve inches is the factory preset. The usable range is approximately 7.25–20 inches.
Will JAM fit every Jazzmaster- or Jaguar-style guitar?
No. Confirm post spacing, body-hole diameter and depth, string spacing, required bridge height and the complete string path. The guitar model name alone is not enough.
Do the locking nuts set bridge height?
No. The internal M4 screws set overall bridge height; the two-hole nuts lock the selected bridge position.
Do I need a different bridge for a wound G or left-handed guitar?
No. The V-Rail saddle orientation can be changed for either configuration, followed by a complete setup.