Fretless Conversion

[Bruce Johnson]

I'm considering defretting a bass of mine. The radius of the ebony fretboard is 12", so once I've got the frets out and the veneer/plastic inserts are glued in could I then level out the fretboard using a 12" radius block?

I'd be filling the nut slots with maple veneer and having my local tech lower the nut slots.

Also, since the fretboard is ebony and I play with flats I'd leave it uncoated.

You don't need a radius block to level out and true up a fretless fingerboard. To do it accurately you shouldn't use a radius block. Use a long flat rigid sanding board, following first along the string paths, and then blending between them.

Here's a thread has a long detailed explanation of the geometry and the technique of truing up fretless fingerboards:

Thread 'What’s the best way to sand a fretless fingerboard and maintain the existing radius?'

Sep 12, 2024

I have a bass with a 12” radius and am going to be sanding and polishing the board with sandpaper grits 150 all the way to very fine grit. The sanding will be surface level—not to remove much material.

Still, I want to ensure I maintain the 12” radius. I read radius sanding blocks are better for carving out a radius, not for maintaining one. So should I just sand by hand ensuring I cup the curvature of the board, applying even pressure as I go from one end of the neck to the other, following the grain?

• Stagelab
• Replies: 83
• Forum: Luthier's Corner

• 

My favorite sanding board for leveling fingerboards is called a Long Board, available in auto parts stores for doing auto body work.

These days, I have 3 of them lined up on a shelf, with 120, 220 and 400 grit paper on them.

 

[fourstringbliss]

You don't need a radius block to level out and true up a fretless fingerboard. To do it accurately you shouldn't use a radius block. Use a long flat rigid sanding board, following first along the string paths, and then blending between them.

Here's a thread has a long detailed explanation of the geometry and the technique of truing up fretless fingerboards:

Thread 'What’s the best way to sand a fretless fingerboard and maintain the existing radius?'

Sep 12, 2024

I have a bass with a 12” radius and am going to be sanding and polishing the board with sandpaper grits 150 all the way to very fine grit. The sanding will be surface level—not to remove much material.

Still, I want to ensure I maintain the 12” radius. I read radius sanding blocks are better for carving out a radius, not for maintaining one. So should I just sand by hand ensuring I cup the curvature of the board, applying even pressure as I go from one end of the neck to the other, following the grain?

• Stagelab
• Replies: 83
• Forum: Luthier's Corner

• 

My favorite sanding board for leveling fingerboards is called a Long Board, available in auto parts stores for doing auto body work.

View attachment 7192039



View attachment 7192040

These days, I have 3 of them lined up on a shelf, with 120, 220 and 400 grit paper on them.

Thanks! The long boards are the ones with the handles?

 

[Bruce Johnson]

Thanks! The long boards are the ones with the handles?

Yes, those are commercially available Long Boards. The long ones without handles are home made, about 30 years ago. The Long Boards are more comfortable to use. Get the sandpaper that they sell for them. It's 2 3/4" wide and comes in rolls, available in many grits. It's good strong sandpaper, cuts well and lasts a long time.

 

[fourstringbliss]

Yes, those are commercially available Long Boards. The long ones without handles are home made, about 30 years ago. The Long Boards are more comfortable to use. Get the sandpaper that they sell for them. It's 2 3/4" wide and comes in rolls, available in many grits. It's good strong sandpaper, cuts well and lasts a long time.

Thanks! The bass in question is a mystery to me. I've owned lots of basses and I've always been able to set them up myself with nice low action. On this used bass I bought recently I can get the action nice and low for the A - G strings, but the E-string has fret buzz I can't get rid of. I took it to a local luthier who found that the nut slots were all too low and there were high spots on the frets, so he replaced the nut and leveled the frets under tension, but I still have fret buzz audible through my amp on the E when I'm playing at anything beyond the lightest possible touch. At this point I'm considering yanking the frets and making it fretless because it's a really nice bass otherwise.

 

[fourstringbliss]

What I might end up doing, though, is to remove the frets myself (which would be the easy part) and then have the tech do the rest. I'd probably spend almost the same amount just getting the tools for this one job and knowing me I'd do less than a perfect job.

 

[Bruce Johnson]

Thanks! The bass in question is a mystery to me. I've owned lots of basses and I've always been able to set them up myself with nice low action. On this used bass I bought recently I can get the action nice and low for the A - G strings, but the E-string has fret buzz I can't get rid of. I took it to a local luthier who found that the nut slots were all too low and there were high spots on the frets, so he replaced the nut and leveled the frets under tension, but I still have fret buzz audible through my amp on the E when I'm playing at anything beyond the lightest possible touch. At this point I'm considering yanking the frets and making it fretless because it's a really nice bass otherwise.

I don't want to put down another Luthier's work, but it sounds like something still isn't right with the leveling/relief/setup. And remember that an E-string will almost always require slightly higher action and more relief than the other strings. My guess is that's what the E-string needs: more relief and slightly higher action.

If you really would rather that this bass is fretted, then I recommend you keep working on it to get it right.

 

[fourstringbliss]

I don't want to put down another Luthier's work, but it sounds like something still isn't right with the leveling/relief/setup. And remember that an E-string will almost always require slightly higher action and more relief than the other strings. My guess is that's what the E-string needs: more relief and slightly higher action.

If you really would rather that this bass is fretted, then I recommend you keep working on it to get it right.

Yeah, that's what I'm thinking. It should be totally possible to get the right action. One of my other basses has the E-string 2mm above the 12th fret buzz free with aggressive playing, and the other one is around 1.5mm buzz free, so it doesn't make sense why this one plays any other way. I talked to the tech about it and if higher tension strings don't fix the issue I'm going to have him fix the issue.

Thanks!

 

[Bruce Johnson]

Yeah, that's what I'm thinking. It should be totally possible to get the right action. One of my other basses has the E-string 2mm above the 12th fret buzz free with aggressive playing, and the other one is around 1.5mm buzz free, so it doesn't make sense why this one plays any other way. I talked to the tech about it and if higher tension strings don't fix the issue I'm going to have him fix the issue.

Thanks!

The first thing to do is loosen the truss rod and add some more relief. Experiment with the relief and action to find a combination that works for you on the E string. Then, keeping the truss rod set at that amount of relief, go back and work with the action on the other three strings.

The point is that the relief on the neck should be set to what the E string needs, because it's going to need more relief than the others. If you optimize the relief for the other strings, then the E string is going to buzz.

 

[fourstringbliss]

The first thing to do is loosen the truss rod and add some more relief. Experiment with the relief and action to find a combination that works for you on the E string. Then, keeping the truss rod set at that amount of relief, go back and work with the action on the other three strings.

The point is that the relief on the neck should be set to what the E string needs, because it's going to need more relief than the others. If you optimize the relief for the other strings, then the E string is going to buzz.

I'll try that. Usually I set the relief and the raise the strings until things are buzz free, trying to keep the strings matching the fretboard radius. After that it's balancing string height and relief to find the lowest buzz-free string height. It's entirely possible that I've just gotten lucky up until this point, and this bass has been sent my way to challenge me...

Thanks!

 

[gt1]

As above, don't use superglue to fill the slots. I did use it to glue the strips of plastic in the slots, though. Super glue is very runny. I spent a bunch of time cleaning it up afterwards because I did not mask well. Acetone dissolves superglue, which is also good to have on hand for separating sticky/stuck fingers. Get a small saw to clean out the fret slots, too. I bought a super thin exacto saw on amazon that worked well. I didn't try to cut the slots any lower. I just drew the saw through the slots to get rid of any leftover bits.

I have used rounds on uncoated rosewood fingerboards without ruining the fingerboards. Some people will say it chews them to pieces and that you should only use flats on an uncoated fretless fingerboard. Fooey on them. Vibrato is up and down the neck on a fretless, not side to side.

Good luck!

 

[gt1]

As above, don't use superglue to fill the slots. I did use it to glue the strips of plastic in the slots, though. Super glue is very runny. I spent a bunch of time cleaning it up afterwards because I did not mask well. Acetone dissolves superglue, which is also good to have on hand for separating sticky/stuck fingers. Get a small saw to clean out the fret slots, too. I bought a super thin exacto saw on amazon that worked well. I didn't try to cut the slots any lower. I just drew the saw through the slots to get rid of any leftover bits.

I have used rounds on uncoated rosewood fingerboards without ruining the fingerboards. Some people will say it chews them to pieces and that you should only use flats on an uncoated fretless fingerboard. Fooey on them. Vibrato is up and down the neck on a fretless, not side to side.

Good luck!

Superglue and baking soda cures to the equivalent of dental acrylic. Its not the best material for this application, but it is a very handy tidbit of knowledge. It does work, is sandable and cures almost immediately. If you aren't going to fill with wood, this works well. It's fast, and inexpensive. Just fill the gap with baking soda, level surface with blade edge, and drip glue in sparingly. Sand lightly. I'd mask fretboard with tape before filling and sanding. Cyanoacrylate (superglue) has cyanide in it. When glue hits the baking soda, a miniscule puff of gas occurs. Cyanide gas. If you try to breathe it and succeed, it won't kill you, but it isn't healthy by any means. Best to wear a respirator. You wouldn't even feel anything honestly, but best to use all safety precautions.

 

[fourstringbliss]

I'm still battling the mystery of this bass. Every other bass I've set up I'm able to set the relief near flat and then adjust the strings to roughly follow the fretboard radius. Usually I end up with the E 2mm or less from the 12th fret and the other strings a similar distance.

On this one I can set the relief close to flat and have the A - G strings pretty close to the frets, but the E needs to be really high (like 3mm) before it's buzz free.

What about a fallaway just for the E-string? I don't understand why this would be a thing except that I can't figure it out, and the frets have all been leveled and a new nut installed. I honestly don't care a bit about playing above the 12th fret on this bass as long as I can have the E-string in a normal position where I'm not getting buzz on the B and C#.

 

[Bruce Johnson]

I'm still battling the mystery of this bass. Every other bass I've set up I'm able to set the relief near flat and then adjust the strings to roughly follow the fretboard radius. Usually I end up with the E 2mm or less from the 12th fret and the other strings a similar distance.

On this one I can set the relief close to flat and have the A - G strings pretty close to the frets, but the E needs to be really high (like 3mm) before it's buzz free.

What about a fallaway just for the E-string? I don't understand why this would be a thing except that I can't figure it out, and the frets have all been leveled and a new nut installed. I honestly don't care a bit about playing above the 12th fret on this bass as long as I can have the E-string in a normal position where I'm not getting buzz on the B and C#.

No, "fall-away" isn't the answer. That will just move the buzz point up from the 20th to the 12th.

I still say that you don't have enough relief on the E string. That's why it's buzzing. You're adjusting the relief down low to optimize the other three strings, and it's not enough for the E. Back off the truss rod, increase the relief, and find a combination of relief and action that works on the E string. Then leave the relief there and set the action on the other three strings.