I spent weeks drawing a headstock in Illustrator, exporting a DXF, and watching Fusion 360 refuse to do anything useful with it. Martin Harmer of Guitar Assembly fixed that in one call: throw the vector file out and draw it natively in Fusion. Here is what I learned building a whole neck from scratch with him.

Why imported DXFs fight you

Martin has seen this with students too. A shape that looks perfect in Illustrator comes into Fusion as geometry you cannot fillet, extend, or edit properly. Sometimes it is one unbroken line, sometimes it is a pile of segments. Either way you end up redrawing it. Starting in Fusion means every line is real, constrained geometry from the start.

Laying out tuners: the non-negotiables first

Before you draw anything pretty, place the parts that have to work.

• First tuner: Martin offsets from the nut by the nut width. On this neck that was 42 mm. He learned it from another builder and it has always worked for him.
• The rest: six tuners means five spacings. Standard modern spacing is 25.4 mm, so 5 x 25.4 = 127 mm. Draw a 127 mm line along the angle you want, then use a rectangular pattern to drop all six along it.
• Edge clearance: leave roughly 14 to 15 mm from a tuner center to the edge of the headstock so the buttons can turn. Martin once got this wrong on an early design and could not fully turn the tuners. Check your actual tuner specs.

Then extend those lines a bit and you have a frame to design inside.

Fillet the solid, not the sketch

This is the tip I will use the most. Keep sharp corners in your sketches, extrude, then add fillets to the solid. A sketch fillet does not behave naturally when you edit it, and you can never set it back to zero. A fillet on a solid gets its own feature in the timeline, so you can change it or delete it later.

Know your intent before you design

I asked Martin to try a tighter radius on the nose of the headstock. It looked fine on its own and then cut right into my logo. His point: it is easy to go down a rabbit hole without a clear plan. We rolled the timeline back and kept the curve that worked with the logo.

The logo, by the way, is one I drew years ago for the back window of my truck. That swoop is why the headstock wanted to look the way it does.

Neck numbers we landed on

• 9.5 inch fretboard radius, mostly because bridges are easy to find at 7.25 or 9.5
• About 23 mm thick at the 12th fret including the fretboard, close to a Fender American Professional modern C
• A profile built from two symmetrical arms: pull them for more shoulder, add a point for more V
• A neck pocket around 75 mm as a starting point
• A headstock around 14 to 15 mm thick, with a gradual transition that is also easier on the CNC

The neck is a loft between profiles, and the heel and headstock transitions are patched surfaces. Martin splits faces first so he can patch one side at a time. Patching everything in one go can leave a dimple you only see in the reflections.

The truss rod changes everything

I want a spoke wheel truss rod that comes out at the heel end. That means modeling the wheel (5.14 mm thick, 12.65 mm diameter) and the block behind it, then planning the access hole so the rod can slide in. That is a bigger topic for another day.

If you want to learn Fusion for guitar building, Martin teaches it. Find him at guitarassembly.com.

Follow along

One guy in a small shop on his father-in-law’s property in Lindsborg, Kansas. IT Director by day, maker by obsession. Equal parts problem solver, craftsman, and curious human. If you’re the kind of person who takes things apart to see how they work, or watches people who do, you’re in the right place.

Uncut shop sessions go up on YouTube and I stream on Twitch. Everything is @carverwoodworking. There is merch in the shop, or you can buy me a coffee.