What is a good curve tool to use to make custom threads?

Using a helix curve is an excellent choice for creating custom threads. This tool generates a three-dimensional spiral shape, which is fundamental in modeling threads because threads themselves are typically helical in nature. The helix curve allows you to specify parameters such as the pitch, radius, and number of turns, which directly correspond to the characteristics of a threaded feature. This flexibility enables designers to create threads that meet specific design requirements, such as those found in screws, bolts, and various fasteners.

In contrast, other curve tools, while useful for different purposes, do not provide the same level of specificity and adaptability needed for thread creation. For example, both the rotate curve and thread curve options might be useful for other modeling tasks but do not inherently generate the helical pattern required for threading. Derived curves are more about creating a reference path based on existing geometry rather than defining a new thread feature. Thus, the helix curve stands out as the most appropriate tool when the intention is to design custom threads in CAD applications like Siemens NX.