I got a cheap calipers from http://shars.com, and the battery only lasts a few days if left in. So that’s a potential problem even if it is highly accurate.
So in summary:
Cheap
- often accurate to 0.001" / 0.02m
- good enough for building a printer
- some display more precision than it can measure
Mid-range
- better fractional measurements
Professional
- better accuracy over longer distances
- absolute measurements rather than relative
- better battery life
- durable
Thanks for all the feedback!
Careful about “durable” - you must treat the caliper jaws with respect. They are usually hardened, but you can damage them and lose your accuracy.
Oh, and as my high school math teacher used to say - you can be very precisely wrong!
I have a hobby that involves kits of parts that were all designed to work together. I used my calipers to measure all of the parts, and quickly discovered that some of the measurements were round numbers in metric, some in fractional inches, and some in decimal inches. As long as there are existing systems that use SAE measurements, SAE units won’t die until all of those old systems are replaced. Given that those systems include the electrical, plumbing and sewer systems for the entire country, I wouldn’t bet on retiring SAE measurements before the end of this century, and probably not the next.