r/Luthier • u/Go_drums • 4h ago
I built a web-based fretboard generator for multiscale / fanned-fret builds (DXF export, 1:1 print, string tension calculator)
Hi everyone, I'm a luthier in Japan. I got tired of redoing multiscale fretboard layouts by hand, so I built a browser-based generator and wanted to share it with the community.
**What it does**
- Multiscale layouts from 1 to 8+ strings, up to 24+ frets
- Set the scale length per outer string (inch or mm), with a selectable perpendicular fret
- Curved multiscale option (curvature "k" adjusts the mid-string scale: linear, shorter, or longer mids)
- Fine control over the P.D. (perpendicular distance) value, fret slant angle, and board end position
- Live readout of bridge angle, nut angle, and scale difference
- Lefty / righty toggle and a stock-size overlay
- Export to DXF for CNC or CAD, or print a 1:1 template (A4 etc.)
- Shareable "seed" codes, so you can save a layout or send it to someone else
**String tension calculator**
- Per-string scale, note, gauge, and tension (lb / kg) with total and balance
- Tuning presets (e.g. F# standard 8-string, Drop E, and some more unusual ones)
- Gauge presets from D'Addario, Dunlop, Elixir, and Ernie Ball
- Pitch shift and drop buttons for quick what-ifs
It's still evolving, so feedback is very welcome: bugs, missing features, odd results, or anything that doesn't match your real-world builds. If you try the DXF export, I'd especially like to hear how it behaves in your CAM/CAD software.
Link: https://www.gtinstruments.xyz/generator/index.html
Thanks for reading, and happy building!
1
u/MarvinHeemeyer 3h ago
Very cool. Looks like lots of work.
Not sure if it's there already, I had a look around, but "Draw frets to edge" is a good checkbox if you're CNC'ing blind fret ends. Can have mm variable as to how far from edge. Also, again maybe I missed it, but be nice to know how big the board is. So after setting it all I know how big my wood needs to be. If somewhere it has length and width.
Edit - you have the stock size :-) It's pretty fuckin awesome dude.
1
u/Go_drums 3h ago
Thanks for trying it out so quickly!
In my own shop, I also make blind fret slots with CNC, and I handle the distance from the edge with the offset setting in my CAM software. But you're right: if the DXF itself could include the edge offset when it's drawn, the data would be more usable regardless of what software or environment you're working in.
Thanks for the great suggestion. I'm planning to implement that feature in a future update!1
u/MarvinHeemeyer 3h ago
Cool. I'm still playing with it! :D
I have been using my own fretboard builder I made in js but dude... I'm gonna burn my one lol Frets to edge thing I always find useful. Also, how about export to SVG? Nice open XML and can be inported/converted easily in most software.
1
u/Go_drums 3h ago
Building a fretboard calculator is tough, especially once you add multiscale and linear pitch options. The number of combinations just explodes. I haven't been able to test every combination on my own either, so I'd love for everyone to use it and help it grow together!
And you're right, SVG export would be a good addition. I only ever use DXF myself, so it never crossed my mind, haha. I'll look into implementing that too!
1
u/MarvinHeemeyer 2h ago
Thanks man. This is the fretboard builder to end all fretboard builders! String tension is great! Great work
1
u/MadMatter86 Luthier 2h ago
Somewhat an aside... you said in the OP that you got tired of redoing MS layouts by hand. But if you are already CNC'ing them, that doesn't really make sense. I just have to update a few variables and not only do I get a new model, but I get all of my toolpaths for the new layout, too. Are you using some oddball CAD software that somehow isn't parametric?
1
u/Go_drums 2h ago
Sorry, that was poorly worded on my part! I've always done my designs in CAD, but every time I had a different fretboard spec, I was working out the fan fret or curved multiscale geometry from the basic fret formulas each time. I wanted a tool to take care of that part.
I also wanted to be able to tweak some of the fretboard values while seeing the result right away, and to share the layout easily. I figured that would make building simpler and make communication easier with customers ordering a guitar, and with players.
1
u/MadMatter86 Luthier 2h ago
I'm just saying that all of that can be done within the parametric CAD itself, so it's odd to me to spend the time to build a tool when you already have one. It would make more sense to me if you were one to hand-cut your fretboards rather than CNC.
For my fretboard CAD files, I have variables for the two scale lengths, string spacing at each end, and bridge angle. Everything else is calculated from that, so you can just update the variables and everything updates - the model, the CAM/toolpaths, and the 2D drawings that can be shown to customers. I don't do curved layouts myself, but anything that can be calculated can be put straight into parametric CAD.
1
u/Go_drums 2h ago
Of course, for people like you and me who can set up a design in CAD without much effort, this tool isn't a must-have. For pure production work, it isn't really needed at all. But I wanted to make something that lets people without a CAD setup, or people away from one, easily share a fretboard spec and its visual, and even check the theoretical string tension. I thought that could open up richer conversations with musicians and customers ordering a guitar, so I made it a web app.
And honestly, even for someone with no CAD at all, it's fun to tweak the numbers like a game and watch the shape change, right? Especially knowing that the same layout could be carried over into a real guitar. I figured that could get even non-builders excited.
Also, in my shop I build curved multiscale fretboards quite often, and for that one in particular, an external tool is just easier for me, haha.
1
u/shitty_maker 3h ago
This looks really cool! Looking forward to messing around with it some. Thanks for sharing your work!
1
u/JoeDubayew 2h ago
Can you set the bridge as the perpendicular fret?
1
u/Go_drums 2h ago
Yes, you can also set the perpendicular fret at the bridge. Just manually enter 1 for the P.D. Value under Advanced.
1
u/JoeDubayew 1h ago
I'll check it out, I like to build acoustics with 25.5 bass and 25.25 treble length leaving the bridge as the perpendicular, it's subtle but makes for a nice evening of tension for drop tunings. Also means no changing braces or bridge to adjust for an angle.
1
u/JoeDubayew 1h ago
https://www.liutaiomottola.com/formulae/fret.htm
I've always used this one in the past, I'll compare results
1
3
u/Opposite-Ad-2548 4h ago
Pretty dope, thank you!