I believe I read someplace that, even though the mariage was over, Winchester continued to make the knives for Simmons up until 1940 on the original Walden Knife Co. equipment, which had been moved to Connecticut after the merger. Shapleigh had the Diamond Edge brand of knives made by a more diverse group of cutleries, such as Schrade, Camillus, and Boker (Although Camillus did some work for Simmons also), so I don't think Schrades really came into the Keen Kutter picture until around 1940.
Eric