Form FB-22 · Rev C · Luthiery Dept.

Fretboard G-Code Builder

Surface · Slots · Cutout · Markers
Checked · 06/12/26
Job Card:
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SHARED
Scale And Frets
Fretboard Layout
Material

OP 1

OP 2

OP 3

OP 4

12345678910111213141516171819202122NUTHEELX0 Y0material length 500 mmwidth 70nut to fret 12 = 323.85 (half of 647.7 mm scale)nut margin 6 mmend margin 12 mm after fret 22string spread 35 at nutwidening to 52 at bridgeboard edge 3 outside the strings, each sideslots stop 1.5 mm short of each edge22 slots, 0.6 mm cutter, 1.5 deeppockets 6 dia, 1.5 deep4 holding tabs, 8 wide x 1.5 tall
stock blankfretboardcutter path + tabsfret slotmarker pocketmachine origin X0 Y0

stock top before surfacingZ0 at crown centerlineedges drop 1.1773 mmtop follows a 305 mm radius8 mm thickslot 1.5 deep, bottom follows the radius (0.3/pass)shaded material removed by the surfacing pass
Cross-section at the widest point of the board (53.5445 mm). Vertical slightly exaggerated for clarity.
Fret Formula
y = L·(1−2^(−n/12))
Widest Fretboard
53.2295 mm
Layout Offset
17.0273 mm

OP 3 · SurfaceReady
Radius the fretboard top
fretboard-radius.nc
OP 2 · CutoutReady
Cut the board outline + tabs
fretboard-cutout.nc
OP 1 · Slots + MarkersReady
Slots, then marker pockets
fret-slots.nc
OP 4 · Markers OnlyReady
Dot pockets, no slot moves
fretboard-markers.nc
✓ Radius Top: ready
✓ Cutout Only: ready
  • Cutout depth is full material thickness; use tabs or strong workholding.
✓ Frets + Markers: ready
✓ Markers Only: ready

FretScale YMachine YBoard WSlot LenX StartX End
136.352653.379941.954138.954115.822954.1771
270.664987.692242.854739.854715.372654.6274
3103.0514120.078743.704840.704814.947655.0524
4133.6202150.647544.507141.507114.546555.4535
5162.4733179.500645.264442.264414.167855.8322
6189.7069206.734345.979242.979213.810456.1896
7215.4121232.439446.653943.653913.473156.5269
8239.6746256.701947.290744.290713.154756.8453
9262.5753279.602647.891744.891712.854157.1459
10284.1907301.21848.459145.459112.570557.4295
11304.5929321.620248.994645.994612.302757.6973
12323.85340.877349.546.512.0557.95
13342.0263359.053649.977146.977111.811558.1885
14359.1825376.209850.427447.427411.586358.4137
15375.3757392.40350.852447.852411.373858.6262
16390.6601407.687451.253548.253511.173258.8268
17405.0866422.11451.632248.632210.983959.0161
18418.7035435.730851.989648.989610.805259.1948
19431.5561448.583452.326949.326910.636559.3635
20443.6873460.714652.645349.645310.477359.5227
21455.1376472.16552.945949.945910.327159.6729
22465.9453482.972753.229550.229510.185259.8148

About this fretboard G-code generator

Fretboard G-Code Builder is a free online CNC G-code generator for guitar and bass fretboards. Enter your scale length, number of frets, string spread at the nut and bridge, fretboard overhang and top radius, and it calculates every fret position and writes ready to run toolpaths for a CNC router: radiused fret slots, top radius surfacing, the fretboard outline cutout, and optional fret marker or inlay pockets.

Each operation exports as its own program in millimetres or inches, with a choice of .nc, .gcode, .tap, .cnc or .ngc file extension, so the output loads directly into GRBL, Mach3, LinuxCNC and most other G-code controllers or CNC senders. Everything runs in your browser, nothing is uploaded, and no account is needed.

What you can generate

  • Fret slots: equal temperament fret spacing for any scale length and fret count, with slot depth, slot cutter diameter, feed rate, depth per pass and spindle speed, following the fretboard radius.
  • Surface radius: stepped fingerboard top radiusing passes for any fretboard radius.
  • Cutout: tapered fretboard outline profile with nut and last-fret margins.
  • Markers: dot, rectangle, diamond or trapezoid position marker pockets, including a double marker at the 12th fret.
  • Fret schedule: a fret position calculator table with cutter-center coordinates for every slot.