# Question: creating the compound radius in a guitar fretboard, is there a jig?



## BFamous (Jan 26, 2018)

So first, I'm not certain if this is the best forum for this question. So my apology if it is not.

Now, I've been toying with the idea of trying to build my own guitar from scratch with some cheap wood as a trial so I can see where it'd just be easier for me to buy decently parts…
One thing I've been mentally struggling with is the compound radius needed for the fretboard. I've read where it needs to be a 10" radius on one end, and a 16" radius on the other end. I can't figure out a repeatable way to do this.

My least bad thought so far is to make a jig from 2×6s, where it follows the needed compound radius and has a slot cut it I need for my blank to rest. The new I could just hand plane and scrape and sand the fretboard to follow the jigs arc.

Is there a better way, or a jig on the market, or a tool for this?

Has anyone done their own compounds radius fretboard before? How?

Thanks for any guidance here.


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## Loren (May 30, 2008)

You can buy radius sanding blocks and sand
it in sections, blending the shapes. Stewart 
McDonald sells those.

In factories it's done with a jig mounted to
a belt sander. Grizzly sells those.

It can also be done with a sharp hand plane
and good judgment. You can make radius
templates out of paste board to check the
shape at various points of the fretboard.

One thing you do need for doing fretboards 
is a really good straight edge. I also use
a "sanding plane" which is a piece of MDF
with plastic laminate glued to the faces to
keep it flat and sanding belt glued to one
side. I find it useful in flattening fretboards
and in leveling frets after they are put in.


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## Andybb (Sep 30, 2016)

For me it's too exacting a process to risk screwing it up so every time I've done it (only 2 times) I've used a commercial product like Stew Mac.


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## BFamous (Jan 26, 2018)

> You can buy radius sanding blocks and sand
> it in sections, blending the shapes. Stewart
> McDonald sells those.
> 
> ...


Thank you for the reply. I'm having a hard time envisioning your sanding plane - but I think I get the idea. Do you mean it's just a long board (at least as long as the fretboard), that is perfectly straight with a belt sander belt attached? That would seem to make sense as it would guarantee the entire length under any one given string is perfectly flat.


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## BFamous (Jan 26, 2018)

> For me it s too exacting a process to risk screwing it up so every time I ve done it (only 2 times) I ve used a commercial product like Stew Mac.
> 
> - Andybb


Yeah, I was debating going that way, but figured of all of the complex pieces needed, the fretboard is one of the ones I should actually be able to make if I just use some patience


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## Loren (May 30, 2008)

Mine is 2 layers of MDF glued together. It's probably
about 16" long and 3" wide. The size was arbitrary
I think because I had some 3" sanding belt. The
abrasive on it if fine, like 150 grit. A length of belt
from a handheld belt sander would be good.


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## BFamous (Jan 26, 2018)

thanks Loren. That makes sense.


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## wormil (Nov 19, 2011)

Here is one I saved on Pinterest.

http://www.kappi.com/blog/2015/09/frasvagga-for-greppbrador/


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## Texcaster (Oct 26, 2013)

The only time I use compound radius is on a double bass FB. I rough them out on the jointer after being glued to the neck, I finish off with a plane and sanding blocks. These fbs are peculiar because the high point is the A string path. A bluegrass fingerboard is much flatter than an orchestral fb. I'm quite happy with a Gibson 12" radius for guitars and mandolins, low action without bottoming out on a bend. There are plenty of online tutes for compound guitar fbs.

http://lumberjocks.com/projects/238402


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## Andybb (Sep 30, 2016)

> For me it s too exacting a process to risk screwing it up so every time I ve done it (only 2 times) I ve used a commercial product like Stew Mac.
> 
> - Andybb
> 
> ...


Maybe if you could just do practice fretboards but they're done after it's put on the neck and that's too much work to remove and re-do for me. If I was doing guitars that would be the jig I'd buy. Every Luthier I know uses commercial ones.


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## BFamous (Jan 26, 2018)

> Here is one I saved on Pinterest.
> 
> http://www.kappi.com/blog/2015/09/frasvagga-for-greppbrador/
> 
> - Rick_M


That's one heck of a jig. I'm now thinking making a jig similar to grizzly's belt sander one may be simpler and probably better since it'll better ensure the entire length under any one string is flat…

Thanks for all of the help and ideas.


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