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Before I trundle off and buy and bunch of stuff I'd like to know the best method for creating a compound fretboard and the tools to do it. My creative nature says to use a string and layout measured arcs on a board, cut them out and sand. I vastly prefer a planed surface am unsure how to do it accurately. Perhaps with radius gauges?

Ideas, links, hair-brained schemes?

Thanks,

-jj

Several people here posted about hand planing a compound radius FB, at least one checking with radius gauges as he went.
I searched "planing compound radius" and found a couple of posts if that helps.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

What tools do you have?
So you want to do just one or many.


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Ken

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Ken

I posted my radius jig in the Fixture, Video and Picture Tutorial forum.

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

I have a ton of handtool, an array of well tuned planes: 22 jointer (no.7), low angle jack planes with several different blades for various purposes, 4 1/2 smoother with a cambered and square blade, scrub plane, a stable of chisels that were clearly forged by some super genius ( they get sharp enough to plane with), two different spokeshaves both are total crap, and a pony keg of determination to build a well playing acoustic guitar.

I'll probably build more than one guitar, it might take a few to get it right and then I've always wanted a twelve string and then there's people who drop by now and then and there's always a need for another guitar.

If it's practical to plane it with radii gauges then I'm all over that. At first I was thinking of making several compass planes to tackle each level of the cone and then taking out the graduations with a straight plane. Going back and forth for sighting the hills would probably drive a person insane. I'll check the threads.

Impressive jig Alex. Unfortunately, I don't own a power router. I do have a hand router and have used it with great success in all kinds of jobs. I plan to use it and carving tools for my truss rod slot. I know Cumpiano says not to but I'm confident in my abilities here.

I don't have very much room in my shop so power tools and large jigs are problematic. But at least I have a shop so I'm grateful. I built my first workbench from tree to finished product in my tiny apartment living room.

-jj

Okay that's fine if you have the skill that should be an easy task with handtools

I'm going to speak into my phone so bear with me

You will need to draw this on paper first

From the drawing you can make a template for each end of the fingerboard

Draw you're nut end radius

Then draw your other and radius

Make your templates

Prepare your fingerboard blank by planing the underside flat and the thickness slightly thicker than a quarter of an inch

Draw the template line on the nut end edge and on the other edge draw that radius template

Now using your sharp planes just go to work planing down the fingerboard surface until one end leaves only that template line and the other and leaves the other template line.




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Ken

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Ken

If I understand you correctly, I'm going to make templates out of paper, cut them out and set them on each end as a visual guide to planing and essentially connect the lines with a plane?

JJ--

If you own the Cumpiano book, then I think you already have a guide to a great way to create a compound radius on the fretboard with a smoothing plane. I wouldn't try to go in other directions unless you are willing to move into power tool territory.

Trying to pinpoint the specific radii is not nearly as important as keeping the fretboard straight along the run of each string. If the nut end winds up with any particular radius that feels good, and you have planed the fretboard straight along the run of each string, it's conical.

Unless you like playing on really tightly radiused fretboards, I wouldn't bother with a compound radius. Above about 12" radius, the difference between a cone style compound radius based on the string spread differential and a plain cylindrical section is smaller than the manufacturing and setup tolerances most people can achieve.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

I just plane along the string paths aiming to get the radius I want at the nut. The fretboard taper dictates the cone shape and therefore the radius at the other end.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

My understanding is that compound radiused fretboards are primarily beneficial to players who do a lot of string-bending, as is common with electric guitars. The string is pulled out of its cylindrical string plane into a conical plane and can bottom out on upper frets. The compound radius mitigates that. The degree of bend required to cause this effect isn't common with many acoustic players, so it's not of great concern with steel string guitars. That's my understanding, but please correct me if I'm off track.


Ken Jones
Mountain Song Guitars

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Mountain Song Guitars www.mountainsongguitars.com

I went back and re-read Cumpiano's instruction. I completely forgot about this and put it in my notes as a question so apologies for asking about something that was right in front of my face. The only thing that isn't clear is Cumpiano says "tilt" the plane but not too much. I'm unsure how much tilt were talking. It would've been nice had he expressed it in degrees.

I played electric for nearly ten years and am all over the fretboard so playability everywhere is paramount to me. I only play acoustic now but still enjoy playing solos and using my instrument fully. On electric guitars I've had I liked the compound radius. Essentially, I want an acoustic that has the capabilities of an electric: low action, OM sized, Florentine cutaway, compound radii.

Unfortunately, I was unaware of precisely what radii I was playing so I'm unsure of exactly what I'll do. I used to own a Collings OM1-A and I liked that fretboard, I searched for their specs and I found they use 14-26, which sounds completely wrong. I also played a SCGC OM that had a spectacular fretboard but I don't know the specs at all. I've also played some individual luthier built instruments that were phenomenal but again I've no idea the specs.

I bend a string here and there and I'm a huge fan of that first fret F barre so this all makes sense for me.

Exactly.

Furthermore, if you want the center thickness of the fretboard to remain constant, and the edge thickness to remain constant as well, this is the only way to achieve it.

My method too, I start with a 16" radius at the nut and check it with a radius gauge, then plane along the string paths until it is all blended in. I check frequently with a straight edge along the string paths. After planing I use a 1" wide levelling beam with 320 grit paper on it to gently sand out any facets that might have been left by the plane.

I guess the radius at the body end of the fretboard is between 20 & 24", but I have never measured it as it seems irrelevant.

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http://www.bobmatthewsguitars.co.uk

By the way, it takes me about 20 mins to create a compound radius fretboard and no jigs or power tools involved

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http://www.bobmatthewsguitars.co.uk

This is what I do too Bob only I use a leveling beam with abrasives (80 grit). What I like about the leveling beam(s) over a plane for this application is I need a length that is slightly longer than the 1st through the 12th which would be a pretty big-arse plane and I would not trust my plane chops with being sure that the cutting was being done in the middle only of the plane. I also need a beam slightly longer than the 12th through the last for fall-away.

I think that using a long enough plane, perhaps #7 for hogging off most of the material and then switching to the leveling beams would make my life easier and more fun too since we all love shavings. Remember too that we work on finished instruments often very, very valuable finished instruments making what ever tool we use need to be safely utilized on a finished instrument perhaps with tuners in place, pups, bridges, etc.

When we refret a guitar with a 16" constant radius we convert it to a compound radius also tracing string paths as you said. We've also measured any where from 20 - 24" radius at the sound hole.

Something to consider when creating a compound radius. The benefits of a compound radius are achieved by the nature of being a compound radius, consistent distance from the strings throughout the entire fret board. As such it's not all that important just exactly what the radius is in terms of magic numbers. Again the benefit is that it's compound so say a 16 - 20 or a 16 to 24 is an improvement and desirable and again exactly what these numbers are will never be important or something that most folks would even ever care to know.

That's always been my thoughts as well. I've never done the math on it but in just thinking it over is seems like one of those things that looks good on paper but in the real world offers no benefit.

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Having said that. I still do a compound radius. I get it close with sanding blocks, usually a 16" radius then finish it off with the Stew Mac sanding beam. I really love that tool. Someone here on the forum recommended it and I can't say enough about it. It's heavy enough to go on it's own just slide it along in the direction of the strings. I use it to level the frets in the same way too.

Exactly

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Ken Cierp

http://www.kennethmichaelguitars.com/

For me, it's just as easy creating a conical (compound) board, as it is to create a cylindrical one, so why settle for second best when the work load is exactly the same?

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http://www.bobmatthewsguitars.co.uk

As hand tool methods go, this is a really good one. I have done it this way, and I liked it.

For me, it is not so much an issue of wanting a compound radius as it is the method for radiusing a tapered fretboard with a hand-plane gives you a compound radius. If I used a radiused sanding beam, I would prob ably be content with the results I get with a constant radius. Since I use a handplane, it would actually take more skill and caution to produce a constant radius on a tapered board (IMHO). I forgot to mention that I too run a straight sanding beam over my string paths to clean up any facets and double check my work but I don't think it gets me too much benefit. Hesh, I would normally agree with you that a long plane would be preferred for good results but that has not been my experience. By that I don't mean longer is worse I just mean that a #4 is all I have ever used and it all comes out straight. Maybe I'll try a #5 and a #6 (18" long bed is about fretboard sized) and see if I like it better. It just seemed like too much bulk. You are essentially freehand shaping the nut end radius and making dead straight planed edges from there. It is more like rolling over an edge with a block plane in that regard. I feel like more plane would cost me some control. The bulk (and length) of a jointer or even a fore plane is nice when making long flat cuts aiming for 90 degrees to the face but maybe not so much here.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

Another low tech way of getting there is to leave the planes alone and just sand by hand. Start out flat, sand a 16" cylindrical radius into the fingerboard with one of the commercially available sanding cauls (the longer the better), then follow that with the 1" leveling beam along the run of each string. Mark the board with pencil marks, sand to make them go away. Lots more elbow grease and dust, but it works. 16" basically tapers out to about 20", and it hardly takes any time to get there with the leveling beam. The first cylindrical radius takes a bit longer, but as long as you start with 16" (not 7" or 9"), it goes pretty fast, too.

I've recently been using a pretty cool router gizmo I cobbled together, and it works great, but I might go back to a lower tech way of doing it. It is important to do this right, but I'm not sure the perfection I get with the router gizmo is necessary at the pre-fretting stage. I got where I wanted to go with the handplane and sanding methods.

I am making my first fretboard right now. I made the blank 2-3/4" wide and 19" long. I had planned on drawing the radius at each end, planing the shape, sawing the frets, then cutting the width. If everything goes according to plan, it will all look and be right when I am done.

Does this sound reasonable?

Ed

Yes except you forgot one thing.
Not sure if you planned on doing this or not.
If you want your edges to be Constant in dimension Will need to do the following.

On the end measure you're nut width and Mark two points. Make perpendicular lines from the bottom surface to the top surface.
Now measure up one 4th inch approximately and Mark a point on each of these lines. Connect those points with your radius.
For the body end measure the exact with of the end of the fingerboard and again draw perpendicular lines up. And then Mark the 1/4 inch points and connect these points with the other shallower radius.

Remove all the wood above the radius lines.

Cut your frets

Saw your taper



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Ken

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Ken