Henry, Just for the record, I stated long ago that while I would agree with the hypothetical aspects of Richard's analysis, I do not and did not think your pods were in fact being moved by stylus drag, but like you say, it is a question open to experimentation.
I performed the analysis of thermal expansion using F degrees and inches. (By the way, I left out a minus sign on the exponent; the coefficient is 1.3 X 10^-6.) By this analysis, an alu bar that is 9 inches long at 68 degrees F (roughly the pivot to spindle distance of an L07D) would expand to 9.000468 inches at 72 degrees F. The expansion of .000468 inches is equal to .0119 mm. This is less than insignificant, even if the construction of the L07D were to be of pure alu, which is not the case (see above). So let's put that to rest, just as I am willing to put to rest the idea that your pod moves strictly due to stylus drag.
Fleib, Try to see the point that if the tonearm and platter move at different times due to differences in resonance or susceptibility to spurious energy sources, then those movements are added to distortions produced by spurious movement of the stylus. Whereas, if the tonearm and platter are well coupled and must move together, then such external sources of energy are cancelled, in effect. For this reason also, we are told to wear seatbelts. I once saw a short movie in which a porcelain cup was put into a small barrel. Then the barrel was thrown down a set of stairs. Of course, the cup inside the barrel was shattered. Then the experimenter strapped the cup firmly to the side of the barrel and repeated the experiment. This time, the cup emerged intact. Keeping the tonearm and platter in consonance has the same beneficial effect. You may disagree, but that is the basis for my thinking, not to mention the thinking of 9 out of 10 designers of commercial turntables.
