Of course, you can take the M.E., P.E. exam, just because you can; but without any real experience can you pass it? And, if you pass it, what will you have to sell without experience, which you could get without the exam. The important thing about registration is that we practice within our experience and real abilities; so get the experience and practice within your abilities, with the P.E. you have. This cuts both ways, you shouldn’t be practicing serious engineering in many areas without a P.E., but I think you can practice outside your specialty as long as this is done within reason and it is within your abilities. There are plenty of P.E’s. practicing both Struct. and Mech. engineering who shouldn’t be practicing either, and many of them cross the lines in both directions. As professionals we grow in many directions, with each new step, as we tackle new problems in small enough steps to allow us to learn and absorb the new subjects, and not cause harm in the process, probably best done under the supervision of someone more knowledgeable in that particular area.