This blog is dedicated to the tender love and care of a Fender Jazz bass belonging to a friend of mine that has been converted from the standard fretted model into a unique fretless version. The nut height, the neck angle, and the bridge setup were all still setup for a fretted bass guitar. This presented a bass that was hard to play and only had a marginal sound. I was asked to take a look at this bass to see what I could do to bring it up to speed.
First things first – I measured the string height at the nut and it was way too high for the proper fretless feel. So, I had to file the nut slots nearly all the way down to the neck to get them close enough. Since you don’t have a huge fret in the way, you can go much lower with a fretless neck.
Once that was set properly, I took a look at the bridge and saw that it had virtually no more room to lower the strings any further without bottoming out the saddles. The truss rod had already been tightened as far it could. So, the only solution to get the strings low enough for proper string action at the 12th fret is to either shim the neck pocket or to install a micro-tilt adjustment mechanism. Luckily, I had just installed a DIY micro-tilt in my relic Stratocaster and it worked like a dream to give me proper string action.
Here’s how I installed the micro-tilt adjuster with step-by-step photos. First, remove the neck from the pocket and check the back-side of the neck to see if it has a metal surface that the micro-tilt will provide leverage against. In this case, it does indeed have a metal surface that will work perfectly. I’m going to countersink a t-nut with a forstner bit (that I picked up at my local hardware store) in the area directly below the metal spot on the neck.
This is a multi-step process and must be done slowly and carefully to keep from wrecking the finish. The first drilling should be only deep enough to recess the head of the t-nut. Here’s what that looks like:
For the next step of drilling, you should take a smaller forstner bit (the size of the t-nut shaft) and drill about half-way through the neck pocket. Then take a small drill bit and drill very slowly down the middle and through to the other side of the neck pocket. Here are the front and back photos (notice the small amount of paint chipped away by the small drill bit – it would’ve been much worse had I drilled all the way through with the mid-sized forstner bit!):
Now take your middle sized forstner bit and drill from the backside towards the front – this keeps the bit from pulling a huge chunk of the finish away if you had drilled straight through from the front side. What you get is a clean round hole with minimal damage to the finish:
Finally, you can finish drilling from the front side and complete the hole. Now, it’s ready to hammer in the t-nut and prepare to drill a hole in the neck plate (that will allow for adjustment of the t-nut without removal of the neck plate). Here’s what that looks like up close:
The final piece of the puzzle is up next. Now that you’ve installed the t-nut directly into the neck pocket, find the biggest carbide (for drilling through the metal neck plate itself) drill bit that will fit cleanly through the t-nut shaft. Now, you are going to screw the neck plate back onto the back side of the neck pocket, but it needs to be backwards. The reason to have it in reverse is simple; you want any lip that may be caused by the drill bit to be hidden when the guitar is reassembled. Now, make sure that the body is level and placed on something solid that you don’t mind drilling through a little – you don’t want to drill a 1/4″ hole into your nice coffee table or something.
That’s it! Your new micro-tilt adjusting mechanism is ready to use. All you have to do is bolt everything back together and use an allen key to adjust the set screw to give you a more or less negative neck angle – the more negative angle, the lower you can set the string height at the bridge. TIP – you only need to turn the set screw about one quarter turn at a time (any more may be too much, take it slow). Also, be sure to loosen all four neck bolts AND the strings before adjusting the set screw – NEVER turn it with tension on the strings or the neck screws.
I also re-wired the bass with new pots and a push/pull series/parallel switch to give it some extra oomph just like those new American Jazz Basses. I’m planning to do the same wiring upgrade to my own jazz bass. So, I will devote another future blog to the play-by-play instructions plus photos.
Here are a few more photos of this truly unique bass: