(6 pivot, 2 1/16" mounting & 2 1/16" string)

FROM CALLAHAM SITE: All of our tremolo blocks are machined from cold rolled non-leaded U.S. steel and are threaded for 10-32 english threaded arms.

When the vibrato bridge was first designed in 1954, it had a machined steel inertia block to give the instrument the required sustain and harmonic content. Over the years, manufacturers have continuously made this part more inferior in order to cut costs. We manufacture an exact replacement block for stripped original bridges, and it can be retrofitted onto any reissue instrument giving a dramatic increase in both sustain and frequency response.

Any 3/16" diameter 10-32 English threaded arm can be used in our blocks. Using our enhanced block with proprietary zero-clearance bushing makes any arm virtually unbreakable.

The original design of the synchronized tremolo although revolutionary at the time has several flaws. These flaws have never been addressed by Fender and they even carry these flaws into the American Standard Tremolos and their Mexican models. The problem is the .205 DIA x 3/16 long counterbore in the top of the block.

This counterbore is also in American Standard blocks. The counterbore creates a tremendous stress riser on the first thread of the trem arm, the weakest section of the arm, because the arm is completely unsupported at the top of the block. The forces developed when using the trem are applied directly to the threaded section of the arm. It doesn't matter if the arm is made from high strength materials, it will eventually fail right at the first thread. The counterbore also reduces the leverage over trem springs. Fender arms also have significant play in the threads making the bridge very slow to respond and making subtle vibrato effects difficult. The Fender solution is a heavy spring in the bottom of the block. This spring causes the threads to gall and suddenly the arm is locked in the block and the only way to remove it is to break it off.

To correct these flaws all of our blocks are produced with a zero-clearance fit Delrin bushing that supports the arm all the way to the top of the block.

This significant improvement makes the arm nearly unbreakable. We say nearly, because the only true way to break an arm off in our blocks would be intentional misuse or abuse. For those of you that play 13's with 5 springs screwed all the way down; play with confidence that our block won't let you down.

The other advantage to this change is the arm will have zero play and will have more leverage over the springs. This will make the tremolo extremely touch sensitive, controllable, and smoother.

Any traditional 10-32 threaded 3/16" arm can still be used, and you gain the advantage of supporting the arm on its major diameter and taking the stress off of the threads.

We have been producing the best sounding bridge available for years. This change makes our bridge even farther ahead of any vintage bridge and rivals the sensitivity of modern two pivot bridges.

Steel is the only material that should be used for the block - but not just any steel - the steel used can not contain any lead. Lead dampens the frequency response and reduces both sustain and clarity.

If you have an import guitar, your block is more than likely zinc (pot metal). Zinc kills both sustain and clarity and your sound. If you have a U.S. made guitar, you may have a steel block but it is either a hot rolled leaded steel, or in the case of the American Standard bridges, a soft cast steel block.

We guarantee you will hear an improvement in both sustain and clarity after installing our block.

Callaham Guitars is only company machining all of our blocks from a cold rolled non-leaded U.S.A. steel.

1) Disassemble the bridge (make a note of saddle location for ease of re-intonation).

2) Start all 3 mounting screws and install trem arm into block.

3) Tighten 3 mounting screws firmly.

4) Reinstall saddles and bridge and re-intonate instrument. Make sure to carefully re-intonate your instrument.

On all our Blocks the threads for the trem arm are 10-32 English. If you have a non-domestic instrument, you may have metric threads. In this case, you need to get an English threaded arm.

On our American Standard Block the threads for the trem arm are 10-32 English. You can use your existing arm.