What's the best way to add radius to...

[ShaneJ]

I am planning to radius a flat fretboard on an older mandolin and refret (of course) too. I was wondering if any of you could give me some advice first.

Which would be easier and/or better -- use radius sanding blocks with fretboard still attached to the neck, or remove the fretboard from the neck and use a radius jig on a belt sander. Or...some other suggestion?

Thanks for your help!

[Chris Baird]

A radius sanding block used while the fretboard is on the mandolin will probably work. It does take some practice to get it right. Maybe try to sand some scrap first; check it with a good straight edge.

[Rob Grant]

If you have plenty of "meat" (thickness) in your old fretboard, it is possible to radius it in place with a sanding block.

You can actually make your own blocks by using a round form (of the radius desired) cover a small portion of it with relatively course sandpaper and rub a soft wood block of the desired size against the form until you transfer the curve to the block surface.

[ShaneJ]

Thanks, guys. I appreciate the help.

[Flowerpot]

Doing it by hand with a radiused block is not a bad way to go. It's easier than having to remove the fingerboard, IMO.

If you go that route, I'd make a cardboard template with the right curvature so you can check your progress. The biggest thing is to keep the sanding even left to right, and to stop as you begin to take material off the center line (halfway between the A and D strings). I've found that I end up using the template and a small, flat sanding block more than the big radiused block both for avoiding the scroll area, and so the sandpaper doesn't keep getting clogged in the same place.