Since the neck involves many different operations and each is different for for classical or acoustic guitars, we have divided this article into a service of articles. This article will apply to equally to classical and acoustic guitars and ukuleles.
Cut the Neck To Length:
Most neck blanks are shipped long enough to not only build the neck, but the headstock and the stacked blocks for the heel as well. When cutting the neck to lengthc compensate for the headstock and the tongue or dovetail for an acoustic guitar and for the upper portion of the head block for a classical guitar.
Note: Read the article on Guitar Neck – Headstock, before proceeding here as there are some different things to consider for the appearance of the headstock and neck joints.
Analyze The Wood Neck Materials:
Once the decision has been made for the Neck Wood Materials, analyze each plank of wood will be used. Mainly we are interested in the end grain of the wood as this will give the most information. If the wood is too rough to get a good view of the end grain, use a sharp saw to cut off the last 1/8″ or so, or take a sanding stick with sand the end grain until the grain can be clearly seen.
Does the grain look a bit like the bottom diagram in the diagram at the beginning of this article? Is the grain within 45 degrees of vertical? If it is not, it will not be very suitable neck stock.
What we want to do is work with the neck wood and allow the grain to give us as much strength as possible. If the grain is anything except absolutely vertical, you need to rip the block right down the middle into 2 halves.
Mirror The Neck Pieces to Book Match:
Next mirror the pieces end for end and have the grain of the wood book-matched when looking at the end grain. This would look something like the top illustration in the diagram above. When the grain is opposed, this works to your advantage. One of the characteristics of wood is that it tends to warp when unrestrained. When the wood is book-matched, the grain has been restrained. In other words as one half wants to warp one way the other half will counteract this force, keeping the neck perfectly straight.
Consider A Neck Center Strip:
Another consideration with both classical guitars, acoustic guitars and ukuleles, is the use of a center accent strip down the center of the neck. Classical guitars typically use a piece of ebony about 5/16″ thick to add a lot of beef to the neck because it is otherwise unreinforced. Acoustic guitars typically use either an adjustable truss rod set in a channel or a rectangular section of high strength steel or aircraft aluminum. It is ideal to use a feature strip directly below these reinforcements that is a contrasting wood also with additional purfling veneers. This adds a lot of strength to the acoustic neck too and should be something that is considered.
Arrange all pieces of the neck in preparation for them to be glued.. If resinous exotic wood is being considered for neck construction, the surfaces of all exotic resinous wood will need to be cleaned thoroughly with Acetone. See our article on Shop Safety about safely working with this chemical.
Use Titebond for Mahogany, Maple, Birch, Walnut or Cuban Mahogany. Use 2-Part Epoxy for Rosewood, Bubinga or any other resinous wood. Spread the glue on ALL gluing surfaces. Place a piece of waxed paper down on your work surface and gently rub all the wood pieces back and forth to evenly spread the glue.
Glue the entire length of the neck with medium sized C-Clamps. Lightly tighten the clamps and check that the pieces are all aligned. If needed tap the high pieces with a plastic tipped hammer. Now really bear down on the clamps and do a glue cleanup as required. Set aside to dry overnight.