Cheap Casting Gets a Redesign

A year or so ago we put in a new front door and had two Baldwin handle sets fail on our new front door in the first six months. Then it dawned on me why the manufacturer included a backup landing plate in the replacement handle set.

Basically they must have known it would fail prematurely.

The thumb latch is a lever that sits on a set of little pins set on a die-cast zinc alloy, shown above, which allows it to toggle up and down. Unfortunately, die castings are often about making things fast, and such parts typically have sub-par structural performance and are prone to stress cracking.

What probably happened is that a tiny crack formed on one side of the casting and propagated every time we squeezed up and down on the handle. One side failed (red arrow) and our door handle starting twisting at an odd angle. That was pretty weird. The upside is that we replaced it with the backup landing plate before we were locked out of the house.

After going through two plates, we bought a new set (potentially unwisely). But we are happy to report that the manufacturer finally figured out it needed to reinforce the casting for the load by reinforcing the area where the pin sets (right image).  Six months in, it’s still working like a charm.

It’s nice when people finally figure things out, but then I suppose that returns can be a mighty powerful motivator.

This post originally appeared in our sister publication Electronic Weekly’s Made by Monkeys blog.