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Several months back I received a 1975 Jazz Bass with a maple fingerboard that was in need of a setup. Once I received the bass it didn't take long to figure out that the neck was a banana (a ton of relief) and the truss rod was not working at all. I was worried if I tightened the truss rod anymore that it would break. After some consulting with a few others (Thanks Hesh and David Collins) it was clear that this was a typical problem of 1970's Jazz Basses since they have a very slender solid maple neck. The obvious choice would have been to replace the neck with a new neck but considering the bass was a wedding gift given to my customer from his new wife he just wasn't excited about a replacement neck. For the repair I planned on installing a new truss rod and carbon fiber stiffening rods with the plan of not refinishing the neck. (spot repair only)

The first step was to machine out the truss rod end.

I then used a slide hammer to extract the truss rod from the head stock.

The skunk stripe was then machined out using my CNC router.

In order to make room from the carbon fiber stiffening rods, I used a T slot cutter on my CNC router to under cut the truss rod channel on the sides. The idea is that I wanted to mount the two stiffening rods inside the neck next to the truss rod. Since this was a maple neck the only access I had was through the back of the neck.

This picture shows the two carbon fiber rods. .125" wide x .300" tall.

If you look close you can see the rods inlayed in the truss rod channel.

I taped off the neck to ensure the epoxy would not harm the existing finish. You can see all the parts that will get put back in the neck. Carbon Fiber rods, lower filler strip, truss rod, and upper filler strip.

I glued the carbon fiber in first, the the lower filler strip, installed the truss rod, and then the upper filler strip. This pictures show the upper filler strip being clamped.


More pics below....

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Brad
Avon, OH

After I removed the clamps...


I then carefully scraped the filler strip flush with the existing finish and the spot finished using nitro with a brush. Once cured I leveld and polished the sport repair. Since the bass was well "road worn" the idea wasn't perfection but to get it to look like it has never been repaired.

Here it is...final pic.

To finish the repair I leveled, re-crowned, and polished the frets.

Once finished everything worked great and the customer was very excited about the result.

Hope this helps the next time your '75 Jazz bass is wacked!

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Brad
Avon, OH

Well done!

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"Act your age, not your shoe size" - Prince

thats very cool precise work and no doubt an improvement over the original....but i''m curious, why not at least try the truss rod and crank it till it broke or stripped, before the in-depth repair?

Good questions. The truss rod nut wasn't moving at all like I had run out of treads. I tried a spacer before the nut but it didn't help. At the time I was 95% confident the rod wasn't broken but it was clear that it working at all. It was puzzling.

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Brad
Avon, OH

Incredible work, Brad.
I salute you for saving an old relic.
It looks like new!
Dan

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