Copying a neck
for restoration
and repair.

The short version

Copying an existing neck is one of the most common jobs a luthier gets asked for, usually because a neck has broken, and usually on something vintage.

The work isn't clever. It's measuring, transferring, cutting, test fitting, and measuring again. What makes it difficult is that there's no drawing to work from. You're reverse engineering an object into a set of numbers, then turning those numbers back into an object.

The numbers from this build

These are the measurements I took off one broken Gibson style set neck. Your numbers will be different, this is what the list looks like.

Measurement	Figure
Headstock length (nut to tip)	7 1/2″ measured, blank cut at 8″
Fretboard start to end of heel	19 7/16″
Fretboard start to body join	15 7/8″
Fretboard start to 12th fret	12 5/16″
Nut width	41.2 mm (1 5/8″)
Blank width / center	2 1/8″, center at 1 1/16″
Heel width, taken from the body	38.2 mm (19.1 mm either side of center)
Nut thickness	3/16″
Headstock thickness	~1/2″ (0.56″)
Neck depth at the nut	0.62″ (5/8″)
Neck depth at the heel	1 1/4″
Truss rod channel	1/4″ wide, 1/2″ deep, plus 1/16″ of curve
Filler strip	1/4″ × 17 3/4″
Headstock width at widest	3 1/2″

Study the original before you touch any wood

Four questions, in order:

1. How was it built? One piece, or laminated? How many pieces, and where are the seams?
2. What is the grain doing? Flatsawn, riftsawn or quartersawn?
3. What species? In practice it's nearly always mahogany, Honduras, American or genuine, all the same thing. Or maple, soft or hard.
4. Is there a back angle on the headstock, and how severe?

A judgement call worth making consciously

The neck I copied for this one came from a cost cutting year and was heavily laminated. I did not copy it that way.

The reason is practical: reproducing the cheap construction would reduce the value of the finished neck. So I built it the way that model was made in a better year, one solid center piece with two "ears" glued on to complete the headstock width.

The shape, the feel and the measurements all match. Only the internal construction is better than the original.

That's a decision to make deliberately, not by default. For a museum grade restoration you copy the flaws. For a working replacement, you usually shouldn't.

Preparing the blank

Rough sawn stock arrives fuzzy, not flat and not straight. Before any marking:

• Joint and plane every face square. Every angle at 90°, every face flat
• Mill to the exact thickness you measured between the seams on the original

Then look at the end grain and work out which face is closest to quartersawn. Growth rings running straight up and down instead of in arcs. That face goes on top, under the fretboard.

Slightly off is fine. The grain running at a small angle along the length is also fine.

Planning around defects

Lay the original on the blank and think about where the neck actually sits inside it before you commit.

Taking the measurements

Work from the same reference point throughout: where the fretboard starts. Everything is measured from there.

1. Fretboard start to the tip of the headstock, add a margin. Measured 7 1/2″, cut at 8″.
2. Fretboard start to the end of the heel
3. Fretboard start to where the neck meets the body
4. Fretboard start to the 12th fret, a midpoint check, so you find an error before it reaches the far end
5. Nut width, halved either side of your centerline
6. Heel width
7. Nut thickness
8. Headstock thickness and back angle
9. Neck depth at three or more points along the length

The 12th fret measurement matters more than it looks. When you're done, you should be able to lay the original fretboard on the new neck and have it fit exactly. The midpoint check is how you catch a problem while it's still fixable.

Finding center, and labeling everything

Find and mark the centerline of the blank. On a 2 1/8″ blank that's 1 1/16″. Every width measurement is taken as half either side of it, and the truss rod channel is centerd on it too.

Check your centerline with calipers from both edges instead of trusting one measurement. You get one attempt at this.

Then write on the wood. By the end there will be a dozen lines and several look alike. Label them, nut, fretboard end, body join, heel end, and redefine any that are faint before you start cutting. Guessing which line was which, with a bandsaw running, is how necks get ruined.

Carry the important lines round onto the side face as well. You need them there for the depth and angle work.

Depth measurements and the heel curve

Use calipers held flat against the top face where the fretboard sits. Take readings at the nut, at the heel, and at least one point between, more if you can.

If the original still has its fretboard, measure at specific frets so the readings are repeatable. If it doesn't, line the parts up as best you can and take the numbers from there.

For the transition where the neck swells into the heel, find where the curve begins, measure the depth at that point, and draw a line between your reference points. Then use the angle gauge and refine the curve by hand.

Cutting it out

Bandsaw to the lines, leaving room for error everywhere. Measure twice, cut once, and cut generous.

Cut the headstock ears from offcuts of the same board and glue them on with ordinary wood glue. Some makers use epoxy; wood glue is the better choice here.

The headstock back angle

This cut wants control instead of speed. A fine hand saw beats a jigsaw.

• Clamp a straight block as a fence to start the cut square, then remove it once the kerf is established
• Cut very slightly deeper than needed, a 64th, a 128th, so the corner comes out sharp rather than rounded. Not more than that

Some necks have a thin tongue of wood extending forward from this angle, sitting under the fretboard. Check the original before you cut.

Fitting the heel

Flatten with a belt sander or a file, then get into the corners the sander can't reach with a chisel or file.

Test fit constantly. This isn't a stage to do in one go, fit, check, adjust, repeat.

The truss rod access channel

The rounded slot at the headstock end, where the adjusting nut sits, is awkward because the bit wants to wander on a curved surface.

The method:

1. Clamp a sacrificial block of wood either side of the neck blank, level with where you're drilling
2. Use a Forstner bit and drill straight down
3. The blocks hold the bit steady and give you a clean, rounded channel at a controlled depth

The easier alternative: do it before you cut the neck out of the blank, while you still have a flat surface and square edges. You'll need a long enough Forstner bit or an extension, and you must keep it perfectly vertical.

The truss rod channel

Beforerouteing, measure the original's channel properly. On this neck:

• 1/2″ deep for most of its length
• Curving down only about 1/16″ deeper through the middle section
• The channel runs the full length into the access slot, it's not a separate drilled hole

Most of the bend is concentrated in one area rather than spread evenly. Find where, on the neck you're copying.

Routing it

If you must go freehand:

• Use an up cut spiral bit. It lifts the chips out and cuts cleanly. A straight flute jitters.
• Low speed
• Very small increments, several shallow passes, not one deep one
• Mark 1/8″ either side of center as guide lines and watch the bit against them
• Feed direction matters: the router will either pull with you or fight you. Go slow enough to stay in control either way

Building the curve

To get that extra 1/16″ through the middle, shim the router base with layers of tape of decreasing length, creating a gradual ramp instead of a step. Then take a final pass. Check with a ruler until the profile matches the original.

The filler strip

A strip of wood covers the channel and holds the rod in place. On this one, 1/4″ wide by 17 3/4″ long, and I used walnut instead of mahogany, which works better here.

Once cured, pare the proud strip down with a draw knife or file, and fill any small gaps from the routing with wood filler, so glue can't find its way in later and reach the rod.

Trimming the sides

Now the router earns its place. Tape a straight, jointed piece of MDF along the line and run a bearing guided template bit against it.

• A bit with a slight shear or taper cuts far more cleanly than a straight one
• Feed direction reverses for the second side, don't simply repeat the same motion
• You get one attempt. Go slowly and watch for chip out

Then a drum sander or belt sander to clean up.

Shaping the profile

You cannot file a neck by eye and hope. You need to know the shape you're aiming for, and that means a contour gauge.

Press it onto the original at the nut, at the heel, and at points between. Each reading is a cross section of the neck at that station.

You can trace those readings and cut card or plywood templates from them, so you've got something to keep dropping over the neck as you work.

Removing the wood

1. Wood rasp to rough it out
2. Draw knife or spoke shave to bring it close
3. Sander and file to refine
4. 60 grit held in a curve, dragged along the length, to even everything out

Remember how little margin you left. At the thickest point you're only a hair over final dimension, so most of your work is on the sides, rounding the profile over, not on the crown.

Getting it even

Sight down the side constantly. It mustn't look like a roller coaster.

Rotate the neck as you sand. Every angle you turn it to shows a different plane, and a hump invisible from one side is obvious from another. Move the neck continuously rather than working one spot.

Use the edge of the sander to blend the heel transition into the main profile.

Testing the truss rod. And when

Lay a straightedge along the neck. A slight back bow at this stage is normal and fine, string tension will pull it forward later.

Then tighten the rod and check again. If the back bow increases, the rod is working. It will work better still once the fretboard is on and levelled.

Gluing the fretboard

The neck must be flat when the fretboard goes on, not bowed either way. Whatever shape it's clamped in is the shape it keeps.

If there's a back bow, clamp the neck down so it takes on a slight forward bow while the glue cures, canceling it out. Check with a straightedge before committing.

A very slight forward bow is recoverable with the truss rod, and a very slight back bow with string tension, but don't plan on either. Get it flat.

Before the glue

• Oily fretboard? Wipe the glue face with acetone to remove the oil, or it won't bond
• Remove every trace of old glue. Wood glue doesn't stick to wood glue, this is the step people skip when they're excited and rushing
• Not too much glue, not too little

Use sanding blocks or cauls to spread clamping pressure, and remove squeeze out while it's soft.

About an hour before you can unclamp. A full day before you touch the truss rod.

Binding

For ABS binding, acetone does the work:

1. Run acetone down the back of the binding
2. Within seconds it goes soft, near enough liquid plastic
3. You have a few seconds to place it where it belongs
4. Ordinary masking tape holds it. Special binding tape exists and isn't necessary
5. Use a clamp where tape won't reach

It sets within minutes. Scrape it back with a razor afterwards to blend it into the profile.

Some bindings don't take acetone, check yours first.

Drilling the tuner holes

• Brad point bit. Never an ordinary twist bit made for metal, it'll wander and tear
• Headstock flat on the drill press table
• A sacrificial backing board, held with double-sided tape. Without it the bit blows out the back as it exits, splitting and chipping the wood

If you still have the broken headstock, you already have the hole positions. A replacement veneer with the holes precut also makes a perfect pattern, glue it on first and drill through it.

One shot per hole. Be certain before the bit turns.

The principles underneath all of it

• Get the body if you possibly can. Standard measurements from the internet are frequently wrong, because the originals weren't consistent. This applies to bolt ons as well as set necks.
• Test fit constantly. Don't do a long stretch of work and then check
• Make templates if you'll build more than one. Everything here can be transferred to MDF and reused, and the second neck will be far quicker and more accurate than the first
• Use a jig or a guide wherever one exists. Freehand work is possible, the truss rod channel here proves it, and every freehand operation adds error

And one thing worth knowing: you can work from photographs. With enough reference shots from enough angles, a neck can be reproduced without ever having it in your hands. Harder, slower, and entirely possible.

Build a Gibson style set neck with a back angled headstock and you can build anything. A Fender bolt on after this is straightforward.