Attaching the Neck to the Body
By John Fisher
"Anything less than a conscious commitment to the important is an unconscious commitment to the unimportant."-Stephen Covey, American author, efficiency expert
This is probably one of the more difficult and less straight forward tasks in building this mandolin. The neck joint (as like I said earlier) has to be strong as there is a lot of tension from the strings. The above drawing shows the way I did it from the end view of the neck. This method is a little easier to do then the dovetail method and it worked good for me. This tapered tongue will fit into a complimentary tapered shaped groove in the neck block that is on the mandolin body. The big trick is to get the right angle of the neck, a snug fit and that the neck will meet the body accurately all at the same time. The neck "MUST" be attached to the body before the back of the mandolin is glued on.
The above picture is the top view of the neck part that fits to the body. You will notice that because of the cutaway and scroll area of the body, the body is somewhat narrow where the neck meets it, so the neck has to be shaped to fit the body correctly.
Here is an illustration showing how to get the correct angle of the neck. The simplest way is that if you were to put a straight edge on the neck (without the fret board) the distance between the straight edge and the top at the bridge area should be about 3/8". So when fitting the neck to the body, this goal must be in mind.
The tongue should fit snugly into the groove. If it is carved right you should be able to lightly tap it down so that the taper makes a snug fit when completely in. Don't make it too tight as if you have to force it in too much you can possibly brake the neck block and that would be bad. If you accidental make the fit too loose, you can put a piece of veneer to tighten up the joint.
After I got the neck to fit just right, I drilled a hole up from the bottom on the outside of the tongue and into the tongue on both sides to insert 1/4"dowels to help lock the joint into place more. This is why you have to install the neck before putting on the back plate.