Neck Building Details

Capture from Vectric Aspire CAD CAM software. This is a great representation of the end product.

Overview of steps to achieve the fretboard (as pictured above):

  1. Obtain DXF file of any guitar neck
  2. Select only the area of the neck to which the fretboard is attached. Use that portion for the outline that will be cut out.
  3. Create sweep rails using two lines that parallel the length of the fretboard and two lines that parallel the width of the fretboard. Each line will stand as individual vectors. Do not join them. The rails should be close to the fretboard outline. Also create a radius for the sweep, as shown in “Exhibit A” below.
  4. Sweep between the rails.
  5. Lay out nut slot, fret markers, and fret slots. Be sure the box is checked as shown below in “Exhibit B.”
  6. Create a cut path to cut the fretboard from the surrounding material.
  7. Create the layout for the fret slots and fret markers. Use the fret scale shown lower on this page.
“Above: Exhibit A”
“Above: Exhibit B”

Order of machining the fretboard:

  1. Fretboard cutout
  2. Nut slot
  3. Fret markers
  4. Install fret markers
  5. 3D finish
  6. Fret slots

All measurements to 1/1000 inch

Truss rod:

Length = 18.00 inches

Channel width = .2545

Channel depth = .3710

Rod Head width = .3575

Rod Head depth = .4480

Head & collar length = 1.817

Wrench access length = .9200

Wrench access width = .2650

Wrench access depth = .3350

Heel butt to beginning of rod: .7950

Neck measurements:

Overall neck length: 25.625

Heel width: 2.2060

Nut length: 1.698

Nut slot width: .1145

Nut slot depth: .0951

Bridge side of nut to heel length: 18.750

Neck thickness at heel contour: .9060

Neck thickness at nut: .8060

Tuner hole diameter: .3880

Headstock thickness: .5625

Rail Sweep

This is the critical component drawing for the rail sweep used in 3D modeling. All contours are based on this drawing. The curved segments control the contouring and their placement and height can be adjusted to create any neck contour.

Below is the render from the rail sweep shown above.

Rough Machining Toolpath Parameters:

.25 inch end mill

Machining Limit Boundary = Model Boundary
Machining allowance = 0.01
Roughing Strategy = Z Level
Profile = None
Order = Level by Level

Raster angle = 135 degrees

No ramp.

Finish Machining Toolpath Parameters:

.25 inch ball nose

Machining Limit Boundary = Model Boundary

Boundary Offset = 0.250 inches

Strategy = Offset

Cut Direction = Climb

Stepover Retract = .015 inches.

Below is the toolpath for the roughing, profile cutout and tuning holes.

Below is the completed render of the neck. Without a boundary offset, the toolpath leaves a small ledge around the neck contour. This ledge is eliminated with the offset.

25-1/2 inch fret scale

Creating blind fret slots


Drill size for pins used during glue-up: #56

Use headstock end of fretboard as reference.

Fretboard length: 19.375

Fretboard length without overhang: 19.0

Fretboard overhang: .2975

Heel to nut length: 18.5

Fretboard width: 2.2060 tapers to 1.688

Fretboard radius, nut slot, fret slots and dots are all cut after the FB has been glued to the neck. Position heel of FB against 1.5 inch block as shown below. Always set up on center line.

Scalloped fretboard Details

To create scallops, create two parallel lines to each fret by offsetting .06 inches in Aspire using the Offset feature. Select the “Both” option. Leave all other check boxes unchecked. Then extend the vectors to meet the sides. Sweep between each rail, creating a new component after each sweep.

Alignment blocks to properly set up FB for machining.

Nut Slot

Headstock end of FB to bridge side of nut: .6495

Fret slot width: .0230

Fret dot diameter: .2340

Fretwire Details

Above: JUMBO fretwire used my modern guitar makers.
Tang is .075 and needs a slot that’s deep enough when radiused to accommodate the tang.
JESCAR Catalog number 57110

Millimeters to inches

Radius comparison

Fretboard radius varies little numerically between different radii. However, the player can easily tell the difference based on preference and years of experience.