Theory #3 - "Wobbling the Works" (a Code for "Sabotage")
It is entirely possible that "wobbly" refers to workers withdrawing efficiency from the job, as if walking on wooden sabots (the true origin of the term "sabotage"). Certainly those walking on wooden sabots would have a wobbly walk! Since the IWW adopted the use of sabotage as a tactic (at least in theory) and the wooden sabot as a symbol for direct action on the job, this could also be the origin of the term. Downing's letter may have been a deliberate fabrication to obscure the "sabot" origin, since, even in 1911, the IWW faced government repression for advocating sabotage.
It is also true that the term, "wobbling the works" a synonym for "direct action on the job" or "sabotage" could refer to making saws "wobble" and therefore cut less sharply, but this could be a later explanation than Downing's Chinese Restaurant story. However no evidence of this origin or the Wobble Saw theory has been located by Leier, whose research on this subject is very thorough.