Those are pretty thin, compared to what I'm used to. I don't like any flex whatsoever, as I use it mostly for a reliably straight and sturdy line. I'll place it against my part inside the machine when I need to touch off a backward facing tool in order to find the zero. It's also useful when I need to center a tool, as I can place it against a flat on my tool holder and make sure it looks parallel with the center of the machine. That way, I have a lot less work to do when I dial it in. I've never used a steel rule to measure things, but I have a couple of them for straight line conveniences. I use a Mitutoyo and a Shinwa steel rule. These are the two most accurate and sturdiest steel rules from Japan.
