Digital Calipers are useful for measure sizes of various small objects, most notable nuts and bolts and other small parts.

Traditional analog calipers, ie. the ones with numbers printed on them, have been available on the cheap for quite a while. More recently, digital calipers have become readily available. A search on Amazon yields some basic $10 digital calipers, and you can spend more depending on your needs & desires.

So how does the basic $10 caliper hold up? Accuracy-wise it is very good, however when adjusting the width of the caliper you need to keep steady pressure and motion on the thumb wheel. If you do not, it sometimes slips a bit and you’ll get an inaccurate measurement. Because of this, it’s always a good idea to reset, zero and measure a second time. The bigger annoyance with this model is the fact that it doesn’t display fractional numbers, only decimal. This might be on purpose, since a small deviation from the exact decimal value might make figuring out the fractional number more difficult.

It’s not a fun gadget, but a very useful one. A definite toolbox necessity.