20inch OM radiused or not?

[Vilikuo]

I'm in the process of building a 20,5'' scale octave mandolin and I'm wondering whether the fretboard should be radiused or not. This far I have experience of playing an ordinary mandolin with a flat fretboard and it seems to work out fine. Is radiusing the fretboard worth all the hassle involved?

[multidon]

This is a personal preference. Are you making it for yourself, or someone else? That being said, with an octave mandolin you are getting towards a more guitar sized instrument than a regular mandolin. And virtually all guitars these days have radiused boards, with the exception of classical guitars. So a slight radius would probably enhance playability for most people. Not that much of a hassle, really, the radius sanding blocks from Stew Mac would make it pretty straightforward. If it were mine I would probably do 12”-16”. If you do this don’t forget to radius the bridge saddle to match. If you leave the saddle straight you can create a “radius” via the slot depth.

FYI- Weber octaves have a 10” radius. Trinity College boards are flat, if I remember correctly. Bruce Weber, whose opinion I respect, says that the vast majority of players he has encountered report a preference for radius boards, reporting to him that they find that they can play longer with less hand fatigue. This is on the Montana Luthierie page.

[Vilikuo]

I'm making the OM for myself and I'm still working on my luthiery skills.
Going with around 16'' radius would probably be a compromise between having some radius and being totally flat. Should the nut be radiused as well? At what point should I radius the fretboard? After gluing it to the neck or before?

[pops1]

There are a lot of vintage guitars with flat fingerboards, I have several and find them no problem to play. Classical guitars boards are flat. Since you are making this for yourself, your personal preference and the style of music you play would be the deciding factors.

[Vilikuo]

I have very little experience of radiused boards so I can't really say what I prefer. What styles of music would lean more towards a flat board or vice versa?

[multidon]

I would recommend looking at the Stew Mac site. Look at their radius sanding blocks. They post usage instructions for all the products they carry. Along with the blocks they also carry the self stick sandpaper which will make the sanding job much easier. They recommend starting with an installed board that has already been slotted and inlayed.

The nut should also be radiused. The critical thing is the slot depth though. You want the nut action to be consistent across the board. Use metal feeler gauges so that you go just enough but not too far. Likewise use a precision ruler marked in mm or 1/32 of an inch to get your desired bridge action, measuring at the 12th fret. Probably you want the bass side a tad higher to allow for thicker strings.

I am not aware of any style considerations regarding fretboard radius or lack thereof. It’s all about player preference. It used to be all boards were flat, so that’s considered “traditional”. Not sure when radius boards were first tried (maybe it was Fender in the ‘50’s?) but for sure they are a more modern development. It makes sense when you think about it. The human hand and fingers are naturally curved when at rest. A radiused board makes barre chords much easier, for example. Most classical guitar players wouldn’t even consider a radius board, they are usually so bound by tradition. But mandolin players, and guitar players of all other styles, have been much more open to it. With the exception of Gibson mandolin fans. Gibson’s by and large had, and still have, with only a very few exceptions (Jam Masters and some Customs) flat boards.

[CES]

If you have or can make the tools, I cast a vote for radius as well.

[pops1]

If there is a store near you go play some guitars with each and try to figure out what you prefer.

[michaelcj]

I have a Clark OM with a 20.25 scale. The fretboard is radiused and very comfortable.

[Hovington Instruments]

I've finished this Octave Mandolin last year with a scale of 21" . I did radiused the fretboard to a 12. ( customer request) I can't really imagine it without a radius.. ( I do own a flat fretboard f5 mandolin) for comparison.

[Bob Schmidt]

I recently finished a bouzouki and radiused the board to 10", and I find it more comfortable than my Trinity Collage which has a flat board. I used the Stew-mac boards to radius, and as multidon said, it is best to do the radius after the board is sloted and inlaid.
It is however personal preference, so it would not hurt to try a couple of guitars with and without to see what you prefer.