Micrometer calipers measure thickness. Vernier calipers can measure both thickness and inside diameter. For the same least count and accuracy, both are similarly priced. Do micrometers have any advantage over verniers (besides size- micrometers being compact)?
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$\begingroup$ Vernier calipers I've used just seem to be a bit flimsier than the average micrometer. It may come down to what you prefer reading but my gut feeling is that I trust the advertised precision and accuracy of a micrometer a little more. Too speculative to put as an answer though. $\endgroup$– AirOct 14, 2016 at 17:05
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1$\begingroup$ "I trust the advertised precision and accuracy of a micrometer a little more". why? $\endgroup$– akmOct 14, 2016 at 17:35
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$\begingroup$ The screw mechanism seems more reliable. The spindle is in pure compression and the frame tends to be much more substantial. Vernier jaws are thinner by comparison, plus subject to moments. In practical use it may not really matter though, I don't use calipers on a daily basis. $\endgroup$– AirOct 14, 2016 at 17:47
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$\begingroup$ There is also an incredible variety of bore gauges designed for measuring ID better than a vernier caliper. starrett.com/metrology/metrology-products/… $\endgroup$– Carl WitthoftOct 17, 2016 at 12:35
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$\begingroup$ Does "vernier" mean that it measures thickness and inside diameter? I don't think so. $\endgroup$– Andyz SmithFeb 7, 2017 at 21:46
2 Answers
Micrometers tend to be used for higher precision measurements and are usually specific to one particular type of measurement (thickness, depth, bore etc) they are defined by their vernier screw mechanism which can be adapted to various functions (the fine feeds on lathes use a similar principal).
Vernier calipers (and their dial and digital equivalents) are a bit more convenient to use and are more versatile, having a larger range of measurement and being able to measure, thickness, length, diameter, bore and depth in the same instrument.
It's common to use vernier calipers for general measurements where reasonable precision is required (say to around 0.1 mm) as they can be fairly inexpensive and are plenty accurate enough for a lot of tasks eg checking if a drill is 10 or 10.5 mm
Micrometers and the like tend to be reserved for higher precision tasks like fine machining and grinding where accuracy better than 0.1 mm is required, especially for repetitive measurements over a narrow range.
Obviously precision will vary with quality but typically a micrometer will have better precision than a vernier caliper in the same sort of price range.
~A micrometer screw gauge has a smaller scale compared to vanier calipers therefore measuring short distances ~a micrometer calipers measures thickness while a vanier calipers measures both thickness and diameter