Tuesday, February 9, 2010

Going Overboard

When relying on screws to support a lot of weight, I tend to go overboard and use more than necessary. Call me skeptical, but I'd rather play it safe.

My dad, a retired nuclear projects engineer, told me about an experiment he and other students conducted in his college's shop class where they calculated and tested the strength of rivets using the knowledge they acquired in strength of materials courses.

They hooked a chain through the license plate holder of a '43 Ford. Dad remembers the details about the car because 1) he's an engineer, and 2) he's a dude.

The two 1/4" rivets of the license plate holder supported the car as the students used a hydraulic lift to hoist the front end about 7" off the ground. They came up with the idea for this experiment because 1) they were dudes, and 2) they were dudes.

Granted, rivets and screws aren't exactly the same thing, but I remember that car experiment every time I use screws for support, as I did when hanging my hand tool cabinet. Despite my Dad's left brain wisdom, I still sank about 30 screws into the French cleat on the back of my cabinet for fear that it would otherwise crash to the ground. The mating cleat is secured to wall studs with 6" lag bolts.

Overkill? Maybe. But I do this every time I use screws because 1) I'm overly cautious 2) I've heard enough ideas-gone-bad stories from my dude friends to question the results of their "experiments," and 3) learning how to calculate screws' tensile, shear, and compressive stress levels is about as interesting to me as watching a fresh coat of paint dry on a restored '43 Ford.

The following video illustrates my method for hanging a small family portrait. It enlists the help of a backer board in the event that you have trouble locating a stud. The stick figure is meant to be pulling a cordless drill out of her pocket, but I realized after watching the video a few times, it looks a little...odd. Ah, well.

video