12-22-2013, 08:18 PM
I'm not sure that I fully understand the construction method, but a couple of mating shapes where the two portions meet should take care of alignment - it can be as simple as two 1"x2"s screwed to one with a space between them, and, on the other surface, a 1"x2" which fits into that space. A couple of "C" clamps or quick-release clamps should hold things together until the rolling section needs to be moved.
Wayne
Wayne