Right, Rhea. I got hung up on the aphorism aspect of this and forgot that I add "clear" whenever some dolt might think I mean center to center. If I mean that, I say center to center, but I still sometimes worry that it's not heard.
I'm still floored by a 36" shelf being 36" wide if it's particle board but 36" long if it's wood with a grain. I suppose plywood isn't counted as having a grain for these purposes....
A good answer is easier with a clear question giving the make and model of everything. "The biggest problem in communication is the illusion that it has taken place." -- G. “Bernie” Shaw