Installing a trussrod adjustment slot on a (bass) guitar body

SkuttleFunk

Senior member
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1,156
I've seen a lot of discussions lately about people needing to remove their necks to adjust the trussrod ... for those who have a body without a trussrod adjustment slot, here's a workflow to add this feature to your instrument body

This job is easier since I'm working an unfinished body where the centerline is readily visible, and it will be covered with a pickguard so the slot won't usually be visible (allowing you room to route a sloppy slot if your router skills are less than phenominal  :D  or should that be  :sad: )

Step 1 is to mark the neck/body centerline, and then draw a line parallel to it 1/2 the diameter of the bullnose (aka core bit) router bit. Once marked, use double stick tape to secure a routing guide for the router bit bearing to follow on. In this example I'm using the smooth edge of a Bartolini pickup routing template

RH09501P-TrussrodAdjustSlot-1.jpg


Step 2 is to route the slot utilizing three passes, each one about 1/8" deeper than the previous

RH09501P-TrussrodAdjustSlot-2.jpg


Here's what the bit looks like in the slot with its bearing following the edge of the routing guide

RH09501P-TrussrodAdjustSlot-3.jpg


And a pair of images of the final results

RH09501P-TrussrodAdjustSlot-4.jpg

RH09501P-TrussrodAdjustSlot-5.jpg


All totalled this took about 30 minutes if I include the time I spent looking for my box of router bits (they were behind something I slid onto the shelf when cleaning the shop last weekend  :confused4: )

It's a simple job that will save you loads of frustration if you have a heel adjust neck and no adjustment slot in your body. Once this slot is installed, the need to remove a neck to adjust the trussrod is completely eliminated. In the case of this bass build, the new owner will simply need to remove the pickguard before turning the trussrod. Nice!  :D

all the best,

R
 

NonsenseTele

Senior member
Messages
8,256
Awesome! But I still want a side adjuster for bass... Gotoh told me his side adjuster could work on bass as far as using a 5mm truss-rod, but I don't know if this is a good idea, what do you think?
 

SkuttleFunk

Senior member
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1,156
Blue313 said:
Nice walkthrough! 

How long the channel should be?

Thanks ... just a little shoptime moment captured from last evening.


IME the length depends on the trussrod adjustment type:

-  if this is a hex-wrench type of socket you'll want it about the length of the short side of the wrench (if you make it too short you can always cut your wrench to length)

- if this is a phillips type of slotted trussrod end then you'll need to base it on the workable screwdriver angle (striaght shaft) or short leg length (for one of those Z-shaped angle screw drivers) ... the slot I installed last night was for a straight shaft phillips screwdriver adjustment, and it's about 3/4 of an inch or so long


I'll also note that if you're using an adjustment tool with an angled shaft, it's preferable to utilize a wider adjustment slot so you don't chip your finish when turning the wrench. I like what Yamaha does with their basses (at least those few I've seen) where they install a wide slot and then fit it with a rubber cup. this allows you to bang the side of the adjustment slot with your angled wrench without chipping the paint if you make hard contact.


you could also utilize a similar workflow to install an adjustment notch for retrofitting for a neck that has a spokewheel type of trussrod adjustment (I really like how these work ... but they are really ugly there at the end of the neck)

all the best,

R
 

SkuttleFunk

Senior member
Messages
1,156
NonsenseTele said:
Awesome! But I still want a side adjuster for bass... Gotoh told me his side adjuster could work on bass as far as using a 5mm truss-rod, but I don't know if this is a good idea, what do you think?

got a link for this adjuster type that Gotoh offers?

all the best,

R
 

SkuttleFunk

Senior member
Messages
1,156
the images look like Gotoh is utilizing a gear/sprocket type of system to rotate the trussrod ... scary!! I would think that you'd have better mechanical longevity by simply adjusting the trussrod directly by turning the rod itself. so what happens if you chip/strip a gear?

since installing a trussrod adjustment slot eliminates the need to remove the neck for adjustments, I don't see how adding this mechanism is a better deal.

sometimes the best solutions are those that are simple in concept, easy to implement, and free  :glasses10:

all the best,

R
 

NonsenseTele

Senior member
Messages
8,256
I always understood as Warmoth used the Gotoh side adjuster.... Do they do it by themselves?

Any idea of how to make one? I got no idea at the moment... I really like the idea of double truss rod, vintage look and NO NEED TO TAKE THE GODDAMNED NECK TO ADJUST :laughing7:
 
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