Just to be clear. As you know, spokes have rolled threads, and in answer to your question you cannot cut new threads, and must roll them.

The reason is rolling forms threads with a crest diameter larger than the blank. Rolling doesn't remove material but, flows it from the valley to form the peak, so the diameter of the blank is equal to the mid-line between the crests and root of the thread, whereas cut threads have a crest diameter equal to the blank they cut into, and a root diameter smaller than that of the rolled thread.

If you can't imagine the difference imagine two different people digging V-shaped trenches to create a thread-like profile. The first person cuts into the ground and carts away the dirt, making threads with tops at ground level, and bottoms at the desired depth.

The second (smarter) person doesn't want to work so hard, so he only cuts half as deep and piles the dirt between his trenches, making small V-shaped ridges in line with the trenches. The total height of his profile is the same as the first, but he's cut only half as deep, and raised the level of the soil, by the other half.