Official Luthiers Forum!

Hello, I'm well underway with my first steel string, parlour style. I plan on doing a 25' radius on the top. There seems to be a couple, or more, ways of approaching it. One would be to sand the whole body to radius and leave it at that. Another would be to sand to radius and flatten out the upper bout after. I know Hesh does this because I got that far in the archives. The latter seems to make a little more sense in my little mind but would be grateful to hear some of the merits of each from the world out there.

Thanks,
Danny

Danny, you want to be concerned about having a hump where the fretboard meets the body. If the top is a pure radius you would tend to get this - i.e. the fretboard joins the body and then goes upwards. For that reason I keep that area flat.

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David White, Toronto

"All my favourite singers can't sing."

I arch the whole soundboard, and I flatten the area where fretboard extension sits on the top with a sanding stick. My top radius is a bit tighter than 25', but it comes out about right for the bridge heights that I use (8-9 mm). One advantage that I can think of is that I can glue all the braces in one go in the go-bar deck as they all have the same radius.

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Rian Gitar og Mandolin

You're right there are lot's of ways to do this. I'm still on my first one but what I did was sand the rim flat and radiused the X brace and radiused only the outsides of the UTB so the fretboard would have a flat surface to lay on. Sanding the UTB like that also helped make a smoother transition to the bridge and avoided the hump.

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Jeremy Douglas

I'm in the radius all then sand the upper bout flat.

Peter

Thanks gents. Flatten it will be...... come...... become.

Cheers,
Danny