Mitutoyo Absolute AOS Digitmatic Caliper
A ruler and a good eye will serve you well on most of your personal projects, but when it comes to the kind of woodworking, metal fabrication/machining, and mechanical engineering work that requires accuracy down to fractions of a millimeter, eyeballing measurements just isn’t good enough. You can avoid all kinds of costly mistakes simply by picking up a high-precision digital caliper tool.
Mitutoyo calipers are generally considered to be the gold standard, with accuracy and measurement repeatability that are second to none. If you’ve ever used a cheap set of calipers from, say, Harbor Freight, these are a mile (or three) above and will make those old things look and feel like a joke.
It extends anywhere from 0″ to 6″ (0 to 150mm) and is accurate to ±.001″, with increments of 0.0005″ (0.01mm) shown on the LCD readout. The thumb roller motion is silky smooth, the tool as a whole is solid and feels great in the hand, and once you’ve set an origin (zero) point anywhere along the slider, it will remember it while you do incremental comparison measurements.
This is a tool you can rely on. and it accordingly goes for $108 on Amazon. Don’t waffle on this one, just get it.