Radiused Fingerboard?

[G7MOF]

I've been playing a few different mandolins recently with radiused fingerboards and really do like them. I have a couple of Fylde flat top Touchstone mandolins and was thinking about having Roger Bucknell of Fylde change one of my mandolins from what I consider flat to a radiused board.
I've spoken to Roger and he has told me of a few things to take into account but also says I could have the board that is on the mandolin at the moment made into a radiused board..
My main concern is how much of a curve to have put on the board as the neck is quite a wide one and I don't know how to measure the ones I've tried as to the amount of radius I want.
How would I go about this?

[crooksj]

Check out this: https://www.stewmac.com/Luthier_Tool...0aAqRDEALw_wcB

[DHopkins]

I think most are made with a 12" radius.

[Larry Nixon]

I think most are made with a 12" radius.

Northridge shows 5.7 inch radiuss....

[DHopkins]

Northridge shows 5.7 inch radiuss....

That's practically flat, isn't it?

[pops1]

That's practically flat, isn't it?

5.7 is a very round radius, 12 would be flatter, and 20 much more flat. I would prefer a slight radius if I were doing it.

[DHopkins]

I must have been having a Maalox moment. I don't know what I was thinking. My bad!!

[G7MOF]

5.7 is a very round radius, 12 would be flatter, and 20 much more flat. I would prefer a slight radius if I were doing it.

So would a 12 be too curved a radius and is there a way I can measure a radius without buying tools I would only use once?
The mandolins I've tried are Eastman mandolins but I can't measure the amount of curve without specialist tools.

[Dale Ludewig]

You could get one of these. They're inexpensive and have many uses. After you get the contour, trace it on a piece of paper. By trial and error, you can draw circles of different radii and get a match. From my experience, 12" is the most common.

https://www.grainger.com/product/2H3...180813113152:s

[Ivan Kelsall]

Dale has it !. However - if you have enough patience,you could actually make a template of the contour using card. All you need is a cheap pair of compasses to draw a series of curves on a piece of card while noting the radius of each curve,cut them out with a pair of scissors & try each one to see which is the closest match. I'd think that you'd only need variations between 10" & 12" radii,going larger in say,1/8" increments - in fact with 10" & 12" radii,you might crack it with those 2,
Ivan

[Davey]

If you want to get the idea of a 12inch radius, you need a pencil and nail separated by a 12 inch bit of string & draw an arc.

[Drew Streip]

My Eastman is, by my best measurement, a 12" radius.

I also took my old beater mandolin from a flat board to a radius using a 12" radius block from LMI. For whatever reason, that one feels like a slightly tighter curve than my Eastman. I think that's because I put larger frets on, and the neck is a tiny bit wider, so there's more of the "circle" present.

[V70416]

Is it going to be a compound radius or cylindrical? Some old Fender guitars have cylindrical radius;so,when you bend the strings they "bottom out".

I believe luthiers differ on how to radius a fretboard. Some having the most radius at the nut;then,leveling out to almost flat at the bridge saddle.

Some builders would disagree with how much radius at the saddle. If the radius of the saddle matches that of the fretboard how does it affect pick angle?

It makes sense to me to have the bridge saddle not-so-radiused as the North end of the fretboard.

Radiusing a flat board is potentially more problematic than flattening a radiused one.

[GarY Nava]

When I started building mandolins (after many guitars) I automatically put a compound radius on mine not realising some were flat. No complaints! So have done ever since. I use 14" radius at the nut to 16" at the end. There's a bit about how I do it in this video
https://youtu.be/fJK5LJJdV9s

Cheers Gary

[Mark Gunter]

My main concern is how much of a curve to have put on the board as the neck is quite a wide one and I don't know how to measure the ones I've tried as to the amount of radius I want.
How would I go about this?

Save your money, print your own radius gauges on some card stock. I'm sure someone will tell me what a bad idea this is, but too late. I've been using my own printed radius gauges a few years, and they're plenty close enough to tell me what radius I'm looking at on guitar necks. Only thing is, I haven't done much with mandolins, but here ya go: http://www.pickguardian.net/wp-conte...ius-Gauges.pdf

[pops1]

Save your money, print your own radius gauges on some card stock. I'm sure someone will tell me what a bad idea this is, but too late. I've been using my own printed radius gauges a few years, and they're plenty close enough to tell me what radius I'm looking at on guitar necks. Only thing is, I haven't done much with mandolins, but here ya go: http://www.pickguardian.net/wp-conte...ius-Gauges.pdf

I am with Mark, make your own. It's easy to do if you want them more durable use a thin sheet aluminum, plexiglass, or brass. All are easy to work with and will last a life time.

[Mark Gunter]

BTW, a contour gauge like the one Dale linked to is a necessity for my shop, for many things. I use the card radius gauge for guitar necks, but buy pre-made radius sanding blocks from stewmac.