Acoustic Guitar Construction

How necessary is it to buy one of those? Is there an alternative that works just as well? Something diy ?

Not real nessesary, just handy. You can center a neck by running a straight edge along each side of the fret board and marking where it meets end of the guitar. If you measure the different between those 2 marks divide it in half and go that 1/2 distance on each side of the center line you will have a mark on either side that can be used to check center of the neck on the body. The neck is centered when a straight edge along the side of the fret board cross right over one of the centered marks on the bottom of the guitar. The point is once you mark where the straightedge should cross it is just as easy and a bit more accurate than a centerline finder.

Having said all of that the centerline tool is pretty handy.

It took me a couple of minutes to visualize that process, John, but I just had that 'aha' moment and now it makes a lot of sense.
Thanks

Personally I would never trust that gadget -- it makes presumptions that the neck edges and or the finger-board edges or both are in correct relationship to a center line that runs perpendicular to the fret slots, its an averaging tool, to me sorta like the "tail wagging the dog." I draw the FB center-line perpendicular to the frets using a white pencil and that line is used as my reference all through the construction process -- on this issue call me "old fashion."

deadedith wrote:It took me a couple of minutes to visualize that process, John, but I just had that 'aha' moment and now it makes a lot of sense.
Thanks

Yup that is exactly what I was saying.

We're supposed to center the neck?

Oh no.

Personally I've always centered the guitar under the neck. :>)
Works for me!

Kevin