On February 6, 2014 I started a bicycle wheel building class that met once a week for 4 weeks. I purchased a H Plus Son TB14 rim because of its double eyelets and classic box section design that is reminiscent of the Ambrosio Nemesis.

Spoke length

Using an analog and then digital caliper, $OLD \approx 120.5mm$. I then measured the flange width to be $\approx 3.35mm$ and the distance between the outside of the lock nut and the outside of the flange, $x \approx 27.5mm$.

$$W_{L}=\frac{120.5mm}{2}-27.5mm+\frac{3.35mm}{2}$$

$$W_{L}=60.25mm-27.5mm+1.675mm=34.425mm$$

Therefore the distance from the center of the flange to the center of the hub is 34.425mm.

In this example each spoke will cross three times so $C=3$. While the total number of spokes, $N=28$.

$$\angle BAC=\frac{2\pi}{\frac{28}{2}}\times 3=\frac{3\pi}{7}$$

I calculated the spoke length to be approximately 300mm.

References