diff b/w vernier caliper & micrometer

I agree with most everything you said.

I got the sense that the OP was asking for a comparison of a plain, non-digital caliper and a non-digital micrometer for measuring OD.

I don't think you will find much difference in PRACTICAL accuracy between the two instruments. And, with these two devices the accuracy of the instrument depends on the hands, and eyes, of the user. I say this because some micrometers can be overtightened by inexperience users, and the graduations are small.

I still have a vernier caliper, but I can see the digital better.

LL

In my experience I have seen a wide degree of accuracy specifications for all three types. So, the point being that you can have a very accurate vernier caliper and a cheap digital with four decimal places, yet the digital caliper is not as accurate.

Verniers suffer from translation errors when read. It takes more skill to read it correctly and the probability of read error is higher than a digital. Also, I can read a digital caliper faster than a vernier or dial.

However, the dial caliper can be faster if you are doing repeat measurements because the right side of the brain does not need to communicate as much to the left side to generate a "value" for the observed input.

Digital requires both halves of the brain to work together to arrive at the computed meaning of the digits.

This is why even glass displays for aircraft typically show a graphical scale for critical values because the pilot can interpret that data faster.

Thanks!

My GA for sure.

Just a comment- I always prefer an analogue micrometer even if choice is between a digital Vernier and analogue micrometer.provided it can do the job.

What is, "a digital Vernier"?

Take your pick

I should get out more!

Thanks.

Terminology can not be made to individuals satisfactions, Everyone knows a digital caliper don't have a Vernier scale. yet everyone call it vernier caliper.

manju.phoenix There is no difference in accuracy out to three decimal points. The calipers are more flexible in their use, inside, outside, depth and range of measurements. Calipers can also be used to check for parallel, squareness, straight edge & pitch. Digital calipers can calculate difference by checking one measurement then zeroing and adjusting to the second measurement such as checking a stroke. It would be difficult to do any of these with a single micrometer Jerrell

Know a man who owns small die hobbing business. (One man show) He swears by plug gages, swears at "very near" calipers. I prefer micrometers. Digital a nice advancement. Don't forget a piece of metal (I used to test fasteners) will expand from body heat when held. Document temperature when measuring "tenths".

Plug guages and Johansson blocks also work well in experienced hands.

A vernier caliper will measure maybe down to .001 if you have good eyes or a magnifying glass. A micrometer will go to .001 and if you have a vernier micrometer you can go to .0001.

Did every one miss the basic?

The micrometer - the job is held between the axis, so the maximum error on the reading is the screw backlash, which is controlled to be zero(or near to it)

In vernier - you read between the extended portion, quite away from the translation axis, so when the pressure is put, the deflection of the tongue give an error (due to the clearance reauired at the sliding axis). And for the axis to slide, you do a clearance, whatever small and this extends due to simple cantilever effect. Due to this for accurate measurements (though the digitals have the least count in 3rd degree of decimal in mm) we never use them, and go for micrometer with the same least count.

The difference is the accuracy Vs Least count.

And you can confirm it, by checking a rod diameter with both. And that too measure at the root of vernier and the tip of the tongues and see it.

Yeap, vernier or caliper is easier to get operator error. Amount of pressure applied will affect reading. The caliper need to be well maintained with all guides as tight as possible while allow it to slide. If the guides are lost, the caliper will rotate around the slide and give you a few thou (0.00x") different reading.

A micrometer could have similar error if operator force the screw. Some of them use friction to maintain pressure while prevent over tightening. Some have a clicking wheel/knob at the end. Final contact should be made with the wheel to prevent over tight and maintain constant pressure with every measurement.

So, which is better, a sledge-hamer or a hamer?

Come on !! read Anonimous Hero posts, but this time pay attention.

Any person with a clue as to what they are doing can obtain reliable and repeatable measurements with a vernier calipers. Otherwise you would not find them in every machinest tool box. They are more capable than some people that use them. I can confidently use the analog version out to three decimal points with my 57 year old eyes. I have every means of measurement in my hands and depend on the vernier calipers the most and they are the most versatile. The machinery I maintain are in the 20 million dollar range. I hope those who are against the vernier calipers are not comparing quality micromiters to a lesser quality vernier calipers. Jerrell