Steve Stevens

Both the neck and the body need to be marked.   The neck tenon will be cut to a dovetail shape to fit into the guitar body mortise.

First, the neck angle must be taken from the body for transfer to the neck.   It really doesn't matter what the exact angle is.   The important thing is that the neck fingerboard surface and the soundboard surface between the soundhole and the neck be a common plane.   The fingerboard will be glued across the joint between the neck and the body and we want this area to be as flat as possible.

The angle is usually intended to be 90 degrees.   Somewhere in the following assembly process this angle may change.   By the time we get to the neck fitting process we really do not care what the angle is, we just want the neck to fit right.   That is why we just use whatever body to top angle we have to work with and go on with putting the neck on correctly.

Note:  When we glued up the neck scarf and then stacked the laminations forming the heel we only roughly placed the nut end of the finger board.   Once the dovetail is completed we will know the exact location of the 14th fret and will use the fingerboard to reverse measure the nut end location. So, as the next step is planned, leave a little extra (1/16" to 1/8") for trimming during the dovetail fitting.   The face of the headplate area will be planed down to make an exact placement for the string nut end of the finger board.

Use the fingerboard to locate the 14th fret measurement.   Draw a square line across the top of the neck blank, then continue this line down each side using the angle reading device that has the body angle measurement.

The t-bevel with the body angle measurement is used to mark the point where the neck will join the body.   (The 14th fret on this instrument.)  The second line is the 3/4" dovetail depth.   The bevel tool is pointing to the tail (away from the headstock) the same as when it was used to measure the body angle.   If the body angle is not 90° and the bevel is not pointing to the tail when laying out the neck, the top of the neck and the top of the body will not be flat.

Trim the neck blank to the second line.   In this case, the cut was made using a bandsaw.   Make as clean a cut as possible since this cut surface will be used for subsequent layout.

Now use the shop built 22° neck layout tool to position the top lines for the dovetail.

With the top of the dovetail drawn in, the lines are next extended down the fresh sawn butt end of the neck blank to the heel using the 15° marking tool.   The 15° layout tool is not the full width of the butt of the dovetail, so it needs to be held to the top layout lines to make accurate marks.  

The 15° tool is designed to be the correct width of the face cut on the body, which corresponds to the inside cut of the dovetail tenon.

This guitar will have a heel cap of walnut to go with the walnut binding.   The neck depth at the heel is trimmed to that length prior to further layout.

This neck is now ready for the next step which will be to cut the dovetail using these layout lines.   The 'x' marks indicate the waste side of the cuts.  

The body mortise is centered on the instrument body along the centerline of the top and along the center joint of the sides where they are glued to the neck block.

Note:   If for some reason the sides do not meet on the guitar body centerline, a centerline must be established to allow the heel cap to be centered on the center line of the back and allow the fingerboard to line up with the centerline of the top.   This is where we need to pay close attention to keeping things centered if the bridge is to line up properly with the sound board.

Layout the face of the body with the 15° layout tool.

By the way, the binding on the top does not need to be carefully fitted in this area because it will be cut away during the mortise cutting process.   Here the binding was glued down with a 1/4" gap.   The back binding does require a nice joint though since the binding joint will be seen.

Here are the body and heel laid out and ready for the next step, cutting the body mortise and the neck tenon.