Judgment unanimously reversed on the law and on the facts and a new trial ordered, with costs to abide the event. Plaintiff, in support of his theory of negligence in the design, manufacture and repair of the power press, offered expert opinion. There is substantial contradictory expert opinion adduced by defendant. We are, however, unable to determine from the evidence or from the defendant’s exhibit of the clutch latch assembly whether the bases offered by the experts in support of their respective opinions are valid, or how the experts reach their contradictory views. The precise question is whether it was possible for the hook of the rolling key to fail to engage the latch while the latch assembly was laterally displaced in its housing because of the backing off — for some reason — of the castellated nut that was supposed to fix its position. The evidence fails to establish a sufficient basis for a resolution of that issue. It may be that the defendant can demonstrate mechanically that it is impossible for the rolling key to fail to engage the latch when the nut is backed off a given number of threads. This record does not warrant our so finding. On the other hand, the plaintiff has not shown this possibility since his expert has not sufficiently developed the basis for his opinion because of his references to “possibilities” and “other factors”. Concur — Breitel, J. P., Valente, McNally and Stevens, JJ.