Answer to brain trust question

Yesterday Kevin (Grandpa love) was asking about how to read a vernier caliper.
Most told him to get a digital caliper or this tool was not that accurate to read this small of a measurement.





I took this as many do not know how to read a vernier caliper because you can read very small readings with one.
The one pictured is inches on top and millimeters on bottom.
But the do make them inches on top and thousands of a inch on the bottom.

But lets look at the tool kevin has.
Since he was adjusting a nut on a turnbuckle he would never get it precise to a thousands of a inch.
So I informed him to get it close and let it ride.
Down to 1/128 of a inch would be close enough.

So he was looking for 0.395-0.397
Since he had 128 scale I informed him that 50/128 is .390 and 51/128 is .398
So 51/128 would be close enough.

But how do you read 51/128 on the scale.





Here is how you read a vernier caliper.
First you find 0 on the bottom scale and read the 1/16 line to its left.
This picture shows 3/8 or 6/16.
I think anyone that can read a ruler can get this so far.
But how do you get it down to 128 of a inch.

Lets take 3/8 and bring it up to 128's
128 / 8 is 16
16 x 3 is 48
So 3/8 is the same thing as 48/128

Now we look at the small scale.
You will notice the 2nd line is just a little past 1/2
And the 4th line is just a little before 5/8
This means we will want to use the 3rd line that is right on with 9/16
So since the 3rd line matches up on the 128 scale we will add 3/128 to our figure from above.

3/128 + 48/128 = 51/128
And that is how you read a vernier caliper down to 128th of a inch.

Holy crap! I got it close ,and it works! Momma said I should stay in school! Great information though, friend of ours is going to work on his lift soon and he HAS to be exact. I will pass this on to him. Turns out 3/8 drill bit was close for one measurement and 7/16 was good enough for the other. If it stops raining we can plow some gardens!

Thank you, John! I hadn't gotten to my book yet, but you certainly nailed it!

I prefer a dial caliper myself. Digital calipers are for those who really do not know what they are doing.

(quoted from post at 15:35:00 02/25/18)
I prefer a dial caliper myself. Digital calipers are for those who really do not know what they are doing.

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Wow....that's quite a statement!!

Like I've always said, it it were not for us "ordinary" people,
some other people would not appear to be so "extraordinary".

John a vernier caliper can be very accurate. His is just a simple stamped one with the lines/scale pretty crude. With a good one you can easily get -/+ a .001 accuracy.

I have both, my vernier is an old Craftsman, made in Italy, and it will measure to within .002. I was given a digital Starrett 20 years ago
and it came in very handy as I worked a lot with both metric and inch equipment and sometimes unknown. People would come to me with an
unknown thread and I would measure it and then I had both thread pitch gauges to determine the thread.

I agree with JD Seller vernier caliper can be that accurate, used'em for years. Not so much anymore. I like the digital myself. One of the main reasons is with a touch of a button I can read them in metric. Many of the parts we manufacture the prints are dimensioned in metric.

You're entitled to your opinion but I can't agree with that statement at all. I have been a machinist for 45 years, started out with the line up the lines style verniers. Now I
use Mitutoyo digital verniers.

And, in my opinion, micrometers, if space permits their use, are much more accurate then any vernier.

Nothing wrong with a vernier caliper. Accuracy can be just as good as a dial or digital. All in the application. A few years back I used to prepare and give the exercises for the "measurement and calculations" portion of the Science Olympiad. I supplied vernier calipers and high accuracy mechanical scales (balances) Even though I warned their hs instructors, many could not read a vernier caliper, some could not even read a finely calibrated mechanic's scale.

(quoted from post at 10:35:00 02/25/18)
I prefer a dial caliper myself. Digital calipers are for those who really do not know what they are doing.

Click to expand...

I've been a machinist for close to 16 years now. I still prefer dial calipers over digital, although I do have 2 digital sets ( 8" harbor freight that I got when I couldn't afford a good one when first starting out, but still passes calibration every year, and an 18" mitutoyo)

When I have to measure the bigger stuff that I can't get with My 18" or onefof the shop's 24", then we break out the verneirs. I think we've got up to 6'.

Donovan from Wisconsin

I'll bet that there was very little formal education in vernier calipers after 1980. That was around the time that slide rules pretty much ceased being taught. When I was in high school there was an informal competition to see who had the flashiest slide rule but in shop class we used the school's vernier calipers.

I carried a Vernier caliper in my pocket for 40 years. Measurements within .001" were pretty easy. If I had to be closer than that I went to my tool box and got mics, telescope gages, etc. I can't tell you how many steps those calipers saved me. And the battery never went dead, they never skipped a tooth, always passed calibration, and Y2K was not an issue. Long live simple!!

Excellent description of how to read a vernier. Also called "very nears". Goes with any caliper, a micrometer is always better.

However, to use a micrometer, you need to know how to read a vernier scale anyway.