Question about gluing and/or radius sanding a fretboard

[Knarbens]

So after some successful builds I screwed up when I wanted to glue the fretboard onto the neck. Since I'm nervous about that topic in general I want to discuss this topic with you guys and rethink my procedure.

Normally I radius sand and fret a fingerboard and glue that to the neck. That always went well, but I doubt it's the best way to do this? Now I wanted to "pre-readius" the board, glue it on and then do the final radius sanding to guarantee a perfect level surface. I clamped the board down just as always (or even better) and thought nothing could go wrong. After I tightened all the clamps and wiped off some of the squeeze-out I saw there's a small slit between the board and the neck down the WHOLE neck an BOTH sides???

I only placed one row of clamps pushing the center of board to the neck. Now I assume there hasn't been enough pressure on the sides of the board or/and the glue (Titebond) made the board bend up??? I think the fretted boards I usually clamped down that way are stiffer and the frets transfer the pressure to the sides as well.

So I see two options now: Do it as always again, or clamp the board down without any radius. When doing the second option I was wondering how do you guys radius the board when it's already on the neck?

Question one: Poll.

Question two: how do you radius sand a fretboard that's already glued onto the neck.

 

[immortalx]

I usually slot the fretboard (un-radiused), cut the taper and glue it on the neck. Sometimes after slotting and cutting the taper, I radius the board and then glue it. Either way, I never put the frets in before it is glued to the neck!

After the glue dries i cut and route the excess neck blank wood using the fretboard as a guide.
To do the radius, I secure the neck (or fretboard blank) on the workbench with double-sided tape and clamp 2 guides on either side so that the radius block fits centered between them.

I posted this photo on another forum. For the gluing process I use 2 metal bars to make sure the pressure is mostly on the outer edges.

I never had a problem with this method.

 

[Adam]

I've tried a lot of different methods. I've glued tapered (but otherwise square) slotted boards to uncarved necks, I've glued fully radiused, bound, and slotted boards to uncarved and carved necks, and I've glued tapered (but otherwise square) slotted boards to carved necks. The only way any of the formed methods have worked for me is with some kind of negative form as a clamping caul. Lately my preference has been non-radiused but slotted and tapered fingerboards to carved and fully shaped necks. That's worked quite well, even when I didn't have a negative form clamping caul. The most recent one I did, all I had was a piece of plywood with a 45 degree V cut into it in a straight line. That V cradled the neck and prevented it from splaying out under clamping pressure, making for a very consistent glue joint.

 

[Renkenstein]

I play it safe. I glue a slotted and rough tapered board onto the tapered neck while the back of the neck is still square. After that's dry and out of clamps, I sticky tape the neck to a granite slab and radius the fretboard. I then carve the neck.

 

[Jay Jillard]

was your truss rod for sure flush? if your truss rod is sticking out at all, you won't get a clean join down the sides of the neck.

 

[Knarbens]

was your truss rod for sure flush? if your truss rod is sticking out at all, you won't get a clean join down the sides of the neck.

You guys really make me wonder now Well ... the ends have been a hair below flush level and the center part is flexible. I checked whether it's in down the whole length and everything looked as always to me ...

 

[mr shankly]

I use exactly the same method as Renk above. Radius and fret after gluing and before neck carve. Its best to fret before the carve so you have a nice solid base to hammer frets in

 

[Knarbens]

Thanks for your answers guys. So when you radius a board that has been glued to the neck - do you just sand freehand or use some sort of fence?

 

[Heretic]

Wherever possible, prefer to glue things together when they're still square. For fretted or lined fretless boards, that means

slotting -> gluing -> radiusing -> fretting (if required) -> carving

I use a fence of sorts. It's just a few layers of MDF stacked up and set parallel to the centerline of the fretboard. I also prefer to use LMI's radius sanding blocks, as they are wider and longer, and you get two radii per block.

 

[immortalx]

Thanks for your answers guys. So when you radius a board that has been glued to the neck - do you just sand freehand or use some sort of fence?

I use 2 straight pieces of wood on either side of the neck. That keeps the block centered.
Sometimes I use a jig/machine I've build to do the radius before gluing the fretboard on the neck.

 

[Renkenstein]

I use the plane stop at the end of my bench as a fence for radius sanding.

 

[mr shankly]

I just sand freehand with a radius block and then an 18" ground metal beam with 100 grit attached. If I'm doing a compound I use 2 different radius blocks and then a lot more work with the sanding beam- works very well

 

[otterhound]

What is the issue that you encountered that you are describing in the first sentence of your original post ?
Bore me with details .

 

[Sawdust Al.]

I do everything on a totally flat and squared off blank like this.

1. Glue the FB blank to the neck blank with many clamps.


2. Cut fret slots. The great thing about doing it this way is that you can use a square along the board blank to make sure the slots run true.

3.Cut the taper.

4. Hold the neck in a Workmate. The great thing about doing it this way is that the workmate will clamp up tight to the taper angle and you are stood high above it to get good pressure on the radius block and have good free hand control and also good vision above the the work station.

5. Last of all I glue on the head stock wings. I do this last so there is nothing in the way when I'm refining the taper.

 

[Knarbens]

What is the issue that you encountered that you are describing in the first sentence of your original post ?
Bore me with details .

Post #34

 

[Renkenstein]

4. Hold the neck in a Workmate. The great thing about doing it this way is that the workmate will clamp up tight to the taper angle and you are stood high above it to get good pressure on the radius block and have good free hand control and also good vision above the the work station.

I didn't know a Workmate would tighten to a tapered board. Man...I keep finding reasons why I should have a Workmate. I always assumed they were a cheap entry level tool without much value in lutherie, but the uses I'm seeing are really making me want one.

 

[otterhound]

What method do you use to locate the fretboard onto the neck ?
One way is to use brad nails in 2 fret slots .
I drill 2 matching holes in the fretboard and the neck and use dowels to locate the board .
This is how Martin does theirs .
Everything is out of sight , perfect alignment and glue is the only thing holding things together .
I use a "surplus" Martin fretboard as my template for drilling these 2 holes .
There are other ways to do this , but these tend to be the most common that I know of .

 

[Knarbens]

Never heard of that before otterhound ... sounds cool.

I use small fences to align the board.

 

[immortalx]

I drill a couple of holes inside some fret slots and insert small nails or rivets.
Those can be seen in the photo I posted above.
When the glue dries I remove them of course

 

[otterhound]

There are many ways to skin this cat .
I just happen to like this one .
A forstner bit is the way to go .
The other advantage being that you can pre-fit the assembly without gluing and make adjustments if necessary .