Perfectly clear. Thanks!

OK, since I have constructed this model out of primitives, and each primitive is perfect in triangular geometry, I can only assume that the openings are being caused by my allowing one primitive to penetrate another? What would be the best manner of using two primitives without opening the geometry? As in butting a round table leg up against a flat table surface? Should I simply make sure they are close but do not penetrate? Is there a better method?

I know this is basic stuff, but I really need to get it clear before I invest a lot of time in constructing meshes.

Again, thanks.