Acoustic Guitar Neck Constructions - Laminated Type

[dhlutherie]

Below is my basic procedure for building laminated Acoustic Guitar Necks. I have kept the information fairly high level. Additional detail can be provided later and will be based upon questions and general interest. I have the complete procedure in PDF format. I have not been able to attach in that format. Accordingly both the text and photo formats are not optimal.

PROCEDURE

BASIC ACOUSTIC GUITAR NECK BUILDING

Introduction

The following information covers my basic approach to Acoustic Guitar Neck (AGN) Building. There are many methods to
build AGN’s, each with their own pro’s and con’s. To date all of my AGN’s have had the following common attributes:

1. 4-7 Piece Laminations (depending on width and center-stripe)
2. ¾” x ¾” Mortise and Tenon Type Joint
3. Double Acting Steel Truss Rod

All of these AGN’s have been built with basic Power & Hand Tools. While it may be possible to work around certain Power Tools the use of a Table Saw, Jointer, Band Saw, & Drill is required. I will cover Hand Tools in later sections.

Figure 0.jpg.JPG (329.7 KiB) Viewed 15274 times

My choice for this construction method is based upon neck stability and strength. I believe that a laminated AGN is inherently stronger and more stable. To this point you may need to take into account the wood type when arriving at final neck dimensions and profile. I have found when working with strong woods such as Maple you may need to thin the neck thickness. Due to the inherent strength of a laminated neck, as well as that of certain hardwoods such as maple, the neck may be so strong that you will not have any Neck Relief. Aggressive Pick-Type guitar players like both high action and high neck relief. The tension of steel strings will usually allow for this “up-bow” or natural bend. It may not with a Maple-Laminated Neck. When building you may want to keep your Neck unfinished and string-up the guitar to check for neck relief. I have actually had to go back and thin finished necks due to this issue. I originally thought that the goal was a straight and flat neck. I have since found that this may not be the case. I’m once again guilty of thinking like an Engineer.

General Procedure

The general procedure includes the following steps. You can consult the KMG website for additional steps such as relieving Neck to Body Joint (undercutting):

1. Blank Preparation – Glue Up
2. Cut Neck Angle
3. Cut Tenons
4. Cut Truss Rod Slot
5. Add Head-Stock Pieces
6. Layout Neck
7. Cut Profile
8. Join Head Stock
9. Layout Initial Shaping Lines
10. Cut Semi-Finish Profile
11. Shape Semi-Finish Profile

Blank Preparation

In this method I will glue up a blank that can yield either one or two necks. It is more efficient to build two necks from one blank. If not there will be a significant amount of waste. When gluing up the blank you will need to determine the required initial thickness. To do this you will need to obtain the Fingerboard width at the neck-body joint, depending on the guitar design. 99% of the guitars will have a neck that meets at either the 12th of 14th fret. Determine what this width is an add approximately 1/16th or 1/8th. Your total blank, including the center-strip will need to add up to this dimension.

Figure 1.jpg.jpg (479.24 KiB) Viewed 1636 times

Cut Neck Angle

On a table saw set your Miter Gage to create an 88.7 degree and cut one or both ends as required.

Figure 2.jpg.JPG (323.81 KiB) Viewed 15274 times

Cut Tenon

On a Router Table cut the tenon to ¾” x ¾”. Make the cuts in a number of steps to arrive at the final dimensions. Make up a backing board that is cut to the same angle’s (88.7 & 91.3 degrees).

Figure 3.jpg.JPG (344.77 KiB) Viewed 15274 times

Cut Truss Rod Slot

On the Router Table cut the required Truss Rod Slot(s). The Truss Rods I use require a minimum slot of ¼” wide x 3/8” deep. I typically cut the slot slightly deeper (1/8”) and then later add a filler strip to suit. You can consult the LMII website for more information.

Figure 4.jpg.JPG (292.71 KiB) Viewed 15274 times

Layout Neck(s) on Blank

Using either a Neck Template or transferring dimensions from a print I will layout the Neck Profile(s).

Figure 5.jpg.JPG (272.2 KiB) Viewed 15274 times

Rough Cut Profile

Using a Band Saw and other methods (Sanding Drum on a Drill Press) I will cut the rough Neck Profile.

Figure 6.jpg.JPG (278.57 KiB) Viewed 15274 times

Layout Final Nut Position

Using your Fret Board, layout the position of the Nut, making sure that the 12th or 14 Fret is exactly at the Neck – Body Joint. Make sure that you add the Nut thickness to the layout. I typically allow for a ¼” Nut. You will need this Line for final cutting.

Figure 7.jpg.JPG (320.09 KiB) Viewed 15274 times

Cut Head Stock Surface

On a Jointer I will cut the Head Stock Face to meet with the layout line just created. Set your Jointer for minimum cuts so that you can “creep” up on the final dimension.

Figure 8.jpg.JPG (330.34 KiB) Viewed 15274 times

Add Head Stock Pieces

You will need to add one piece on each side of the Head Stock to accommodate the final Head Stock Profile. I thickness the wood slightly thicker than the rough Head Stock and then glue in place trying to maintain a close fit on the front side of the Head Stock.

Figure 9.jpg.JPG (305.66 KiB) Viewed 15274 times

Layout Head Stock Profile

Using a template of the Head Stock, layout the finished shape. Be careful to layout to the Nut.

Cut Head Stock Profile

Using a Band Saw cut the Head Stock profile. You may also want to use a Drill Press or Spindle Sander to generate the final profile.

Layout Initial Shaping Lines

Using some basic drafting tools such as a 45 degree triangle you will to determine measurement points that can be transferred to the rectangular section of the rough cut Neck. Additional points at 22.5 degrees can also be added. I make profiles for the 1st and 9th Frets. See the following illustrations. This approach will create a round neck profile. Different profiles such as a “V” style can be created in similar manner. Spend time making your profiles on paper before working on the Neck.

Figure 10.jpg.jpg (397.86 KiB) Viewed 1636 times

Figure 11.jpg.jpg (251.22 KiB) Viewed 1636 times

Shape Initial Profile

To cut the initial profiles you can use Spoke Shaves, Wood Rasps, or other devices. Holding the tool at 45 degrees - work to the layout lines. When this is complete hold the tool at 22.5 degrees and work to the remaining layout lines. When complete you will have a faceted Neck nearly round in profile.

Figure 11-5.jpg.JPG (240.44 KiB) Viewed 15274 times

Figure 12.jpg.JPG (248.8 KiB) Viewed 15274 times

Shape Semi-Finish Profile

To develop the rounded profile you will need to sand the Neck with Sanding Strips. This is done by using a back and forth motion similar to shining a shoe. Try not to remove much wood from the edges as you want to leave some material for final shaping after the gluing of the Fret Board.

Figure 13.jpg (278.75 KiB) Viewed 15274 times

Figure 14.jpg (285.86 KiB) Viewed 15274 times

[Dave Bagwill]

Now that was a great tutorial, and a very valuable addition to those of us involved in the craft/obsession/hobby/profession etc. Thank you very much!

[TonyinNYC]

Great tutorial Dave! Thanks!

[Kyle Barbour]

Very nice. You make it look very doable.

[John Parchem]

Thanks,

This is timely. I am doing my final neck carving today. I do not use spoke shaves, but I do use wood rasps in much the same way. I run the rasp along the neck while cutting down to make sure I get a smooth even cut along the neck. I can see how a spoke shave would be quicker though. You description of the angles to hold tool really makes sense to me now.

Thanks again for posting this.

[Dave Bagwill]

I've got a couple of questions.

First, can you explain this step any further? I'm having trouble envisioning it for some reason:
"Make up a backing board that is cut to the same angle’s (88.7 & 91.3 degrees)."


Also, how would the above procedures differ when building in a center strip of a different wood?

Thanks

[dhlutherie]

The Backing Board is used for two reasons. First, it provides a means to push the neck glue-up across the router table, insuring that it is also against the fence. Sort of like a mitre gage without a slot in the table. Second, it backs up the neck glue-up to minimize tear-out at the end of the cut. This is typical when routing, especially with cuts perpendicular to the grain. Remember that you will have cut the end's of the glue up to match your desired Neck Angle. On one side you will have 88.7 degrees, flip the glue-up over and you will have 91.3 degrees. The backing board needs to have identical angles so that it will in perfect contact with both the Neck Glue-Up and the Router Table Fence.

One other recommendation: Make your Neck Glue-Up slightly wider (taller) than what you need. By doing this you can run the glue-up over your Jointer to remove the Routing Tear-Out.

Center Strips are just another layer added in the Glue-Up. I have done both one and three ply Center Strips. Make sure to keep your boards oriented properly. This information is included above, but it does not show with the other pictures - you will need to click on the attached link.

Let me know if this answers your questions.