Makes sense, David. I do have to wonder though, how they managed to incorporate hand checkering during all those years previously in a cost effective manner. Checkering in the big gun companies was historically the province of women who I bet didn't have those skills before applying for the job and as such needed an expensive learning curve. I've seen factory pics (I don't recall the factory) of long benches of frowsy looking babes situated in front of big clear windows bathing them in sunlight. I wonder too if it was a good paying job that was rarely abandoned once acquired- leading to them staying on forever. When checkering on factory guns became commonplace in the 20's-30's I can see the companies scrambling to hire and train a legion of young checkerers who then stayed at it until they just couldn't drag themselves into work anymore which would've been, by then, the late 50's early 60's. Recruiting and training the next generation was avoided by employing machines instead.
Addendum: Given the era, I wouldn't be surprised to learn that the checkering women were paid less than if the job were occupied by men. That may have contributed toward the cost per gun effectiveness too.
I doubt that unionization had much to do with piece work versus hourly rate. As a veteran of managing union shops (United Steelworkers) I can state that piece work burgeoned under those conditions. In fact, a strong union could make the piece work system thrive- it gave them infinite grounds for negotiations. God, the horror stories I could tell...
