Official Luthiers Forum!

I know that this has been beaten to death here but I just have to ask...

A good friend has obtained a 12'x2"x6" Honduras mahogany beam from a house built in the '20s.
He's cut it into 12 30x3x7/8 blanks plus a 4'x6"x2" board.
The beam is obviously flatsawn

should I use it for necks or not

You can turn a flat-sawn board on edge and it's quarter-sawn - perfect for a laminated neck.

thank you.

_________________
"Preoccupation with an effect gives it power and enhances the error"
from "Your Owner's Manual" by Burt Hotchkiss.

The neck on my tele is obviously flatsawn. Use away either as is or as a lamination.

_________________
http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Mahogany is one of the most stable woods and can be used either way.

Oh man I would have loved to score a nice find like that!

Other than appearance, I have found no credible reason to prefer QS necks over flat sawn. Violins and Fenders are almost always flatsawn, in a wood (maple) that is less stable than many others.
And contrary to widely held opinions, QS wood is generally no stiffer than flatsawn.

_________________
John

In fact, depending on the species, flatsawn is stiffer. I can't find the link but there are some publications that show that at best, QS is equal to FS in stiffness in certain species but never stiffer. If I recall, it has to do with the difference in density of the early wood compared to the late wood. The closer they are, the more isotropic the material will be.

All that said, the difference in stiffness is very small and not really worth worrying about.

_________________
http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

I'm building a guitar in a class that meets every 2 weeks.
Last night the instructor said not to use this wood unless I want a bumpy, twisted neck.

I'm very inclined to take someone like John Arnold's advice over the instructors but I'm thinking I don't want to go against the grain, as it were, with the instructor.

Having said that, I really want to use this wood.

I would rather have wood that I really knew was old than that bought somewhere, and probably kiln-dried. Your old wood has been through so many expansion/contraction cycles that any internal stresses will have been relieved.
Use the old wood.

Use can use the instructor's wood, but shadow him and build a neck blank out of your friend's mahogany too. Put that neck blank aside for a year. Then you can come back and see for yourself. No reason to take anyone's word for it. If you want to get fancy, do the same with some rift sawn maple and see what you get. This is a cheap and easy experiment to run.