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surdo
05-05-2016, 11:11 PM
What sort of grain orientation should I look for when choosing wood to make the various parts of the instrument? With the top, I gather it should be from 1/4 sawn wood and with the end grain running perpendicular to the face. Does this also apply to the sides and the back of the instrument? I have some nice wood planks at home for example that I'd like to have milled into sheets. It's the right type of wood for sides and back plate with good smooth surface characteristics. The end grain however is pretty much parallel with the face of the wood. Is that OK for sides and back? When is the grain pattern of structural importance and when is it just aesthetic? Does it depend on the type of wood? If someone could please also talk about the grain for the other bits: neck, bridge, finger board, internal blocks, that would be a big help. Thanks.

ProfChris
05-06-2016, 12:25 AM
Vertical grain is also preferable for sides because it's more likely to bend evenly - the kind of grain orientation you describe may well cup during bending. But if it doesn't, or not so badly that you can't sand out the cupping, then it should be ok structurally. Runout is important here - too much and your sides will probably snap or splinter during bending.

The back suffers from the same shrinkage risks as the top, so again vertical grain is safest structurally. If you have a pretty, flat-sawn piece for the back you could reduce the risk by glueing it up in low humidity and designing a decent dome into the back.

Neck - for a soprano I'm not too bothered because the neck is so short. My concerns here would be (a) twisting, so I'd like the grain to be pretty straight, and (b) carving - if the grain reverses and curls everywhere, particularly at the heel, carving is much harder.

Finger board - vertical grain shrinks least, and if the fingerboard shrinks the fret ends stick out.

Blocks etc - I don't care much, these are small and shouldn't move a lot.

Overall, vertical grain makes construction easier for pretty much every part.

But vertical grain is often less visually attractive than other cuts, and these can be used successfully if you know how (up to a point - burls, for example, won't work structurally so have to be laminated).

surdo
05-06-2016, 01:14 AM
Very clear, thanks.