Welcome to the group, but, you have not supplied enough information to form practical suggestions.
There are also conflicts that will add to the confusion. Fine threads in aluminum is not a good idea, especially so if this thing is going up and down frequently.
How frequently will it be going up and down?
Will the threads be regularly lubed or set and forget?
Steel type? Whatever is best suited to the application and at this point we are left guessing.
A single "stud" may not be the best option but a picture would be worth 784 more words.