I want to have dimensions controlled by equations. I have several holes and counterbores, and I want to change the diameters and depths depending on what thread size I’ve chosen. Thread sizes would be 1/4-20, 3/8-16, M6 and M8.

I’d like to specify something like: if thread size = M6, then c’bore dia = .406

But it doesn’t appear I can use text strings in equations. What do you recommend?

Also, I can't control hole sizes with equations, so I have to use revolved cuts. Is that right?