As a professor in manufacturing processes, I’ve always leaned toward forged springs over cast due to their superior grain flow/structure and toughness. That said, I’d take a machined spring, like the ones Jim Kibler produces, over a cast one any day. The precision of machining, along with the ability to quickly tweak designs without revising molds or managing casting schedules with outside companies, makes it a better choice from a manufacturing perspective, at least at the scale we are talking about here.
In terms of function, there’s probably not a nickel’s worth of difference between well-made springs of any type. But Jim’s approach offers real advantages over the other processes in terms of consistency, scalability, and ease of production—qualities I would be looking at if I was doing what he is.
Jim, if you're ever in the mood for an experiment, I’d love to get a couple of our automation students involved in designing a lock testing machine. It’d be fascinating to cycle one of your locks 10,000 or even 50,000 times and see how it holds up. Could make for a great hands-on project—and some interesting data.
