Dial Caliper measurements

I know everyone has their own ways of using a dial caliper, but What is the best way to use them to measure an outside diameter on a round part? I have heard and seen people use them at an angle when measuring and even trying to measure with them as straight as possible.

I also know that you should not use the "tips" of the caliper because they will measure as far as 0.002" or 0.003" than the middle of the caliper blade.

This article describes what you're looking for: http://littlemachineshop.com/Instructions/UsingCalipers.pdf
Or perhaps this one: Quality 11: Caliper Basics
This one's a bit long-winded, but it has lots of pictures: https://www3.nd.edu/~jott/Solids/Lab_equipment/how_to_read_a_dial_caliper.pdf

crb06 said:

I know everyone has their own ways of using a dial caliper, but What is the best way to use them to measure an outside diameter on a round part? I have heard and seen people use them at an angle when measuring and even trying to measure with them as straight as possible.

I also know that you should not use the "tips" of the caliper because they will measure as far as 0.002" or 0.003" than the middle of the caliper blade.

Click to expand...

I know you from another thread you started so I know I can be bluntly honest. I know in advance that my post will ruffle a few feathers but so be it.

The first two links in post #2 I regard as both informative and thus excellent. Have in fact printed a copy of the first one for my “library”.

You are an apprentice at a small shop and have started, or are about to start technical school. You write “dial caliper” and I don’t know if you really mean a dial caliper but not important as all 3 types (vernier, dial and digital) should be used the same way. One of the first things an apprentice learns at our technical schools is how to use a caliper – CORRECTLY. I’ve demonstrated at technical schools here in Denmark (plus one in the USA) and in fact will be doing so again next week in the same town as Grundfos.

Grundfos | The full range supplier of pumps and pump solutions

“You know everyone has their own ways”. Maybe, but I’ve seen how caliper manufacturers (including Mitutoyo) use and test the calipers and they all do the same. The thumb rest or roller is there for a reason. If you are using a caliper up to 8”/200mm and using more than one hand you’re doing something wrong. Either that or measuring a very unusual dimension on an unusual part.

“I also know that you should not use the "tips" of the caliper because they will measure as far as 0.002" or 0.003" than the middle of the caliper blade.”

I certainly hope you don’t know that. It seems to be a sad fact that many in the USA are expected to supply their own measuring tools including calipers. This means that many will use their caliper for as long as possible and when the time comes to renew buy another as used because it is cheaper than a new. Any “extra” inaccuracy is either because the jaws are worn, too much slack on the sliding jaw (this can be adjusted on most calipers) or too much measurement pressure.

All caliper manufacturers I know make their standard calipers to the same standard and to the same manufacturing tolerances.

Digital Caliper Accuracy - YouTube
those are my hands.

It’s no secret my preference is a digital caliper and for several reasons. After zeroing then you can see the measurement result plus, when it is necessary most can show the result in both mm and ins.

I’ll stop here but have a feeling this could be a lengthy thread.

Thanks yall!

All of the above and for a guy who might ask the question it is good to often use a good micrometer to read various parts to a few tenths, then read with the calipers and see how the measurement compares to your feel and the quality of the device. That will tell you what accuracy you might expect.My old 1960s Helos vernier I trust to about .003 on a good day even though it reads .001. My dial .002 to .003, My Brown & Sharpe to .oo1 even thought it reads to .0005

michiganbuck said:

All of the above and for a guy who might ask the question it is good to often use a good micrometer to read various parts to a few tenths, then read with the calipers and see how the measurement compares to your feel and the quality of the device. That will tell you what accuracy you might expect.My old 1960s Helos vernier I trust to about .003 on a good day even though it reads .001. My dial .002 to .003, My Brown & Sharpe to .oo1 even thought it reads to .0005

Click to expand...

You forgot a few exclamation points.

Too often I see people measuring with any old calipers when there's a tolerance of +/- 0.001 when a micrometer could have easily been used to measure that same feature.

Most old timers will just about smack calipers out of your hand for measuring round stuff with them...even still, they are good for an aproximation but no good for accurate measurements...+/-.005, sure that's about as close as I'll go. I hit my jaws with a high number Arkansas stone from time to time, cleans em up good. Otherwise clamp a piece of paper between the jaws and pull it out.

Learn to use mics, it'll keep you more accurate.

michiganbuck said:

All of the above and for a guy who might ask the question it is good to often use a good micrometer to read various parts to a few tenths, then read with the calipers and see how the measurement compares to your feel and the quality of the device. That will tell you what accuracy you might expect.My old 1960s Helos vernier I trust to about .003 on a good day even though it reads .001. My dial .002 to .003, My Brown & Sharpe to .oo1 even thought it reads to .0005

Click to expand...

Quite a bit has changed in the past 60 years. Maybe about time you moved into this century.

New calipers are very good.
Used a few thousand times maybe not and any measurement tool in my shop gets used a lot.
Mics do not go out as quickly.
QC departments don't use and abuse measuring tools like the floor so they will give very different opinions. Not wrong just different usage.
If you run a centerless one learns not to trust a normal mic quickly for dias and second check with a tri. (how can my part be in on two point and out on a three point circle?)
....and there are cmms......not the best gauges in the world and full of their own problems.

Yes, I use the flat section inside on dia. measurements and try to squeeze it to straighten out the instrument. This added pressure adds abbe error but I'm not working in tight numbers with calipers.
By far Gordon is our expert here on calipers and has probably forgotten more than we all know. This guy literally lives and dies in this world.
Bob

plastikdreams said:

Most old timers will just about smack calipers out of your hand for measuring round stuff with them...even still, they are good for an aproximation but no good for accurate measurements...+/-.005, sure that's about as close as I'll go. I hit my jaws with a high number Arkansas stone from time to time, cleans em up good. Otherwise clamp a piece of paper between the jaws and pull it out.

Learn to use mics, it'll keep you more accurate.

Click to expand...

My suggestion would be that you learn how to measure. What you've written isn't only just stupid but suggests that maybe you should find a new line of work.

I get you don't know how to use a caliper so don't offer advice on it.

Sparky961 said:

You forgot a few exclamation points.

Too often I see people measuring with any old calipers when there's a tolerance of +/- 0.001 when a micrometer could have easily been used to measure that same feature.

Click to expand...

If the tolerance is ±0.001 then of course a micrometer should be used in preference to a caliper.

From what I'm reading I can can certainly understand why the US is losing market share in global industry.

A visit to some of the shops and companies I know here would be a real eye opener.

Technique is important, for sure. My accuracy with digital caliper improved when I learned to make a habit of closing it on the part by squeezing the jaws together with my left thumb and forefinger rather than by pushing the moveable jaw with my right hand while holding the bar. If you push too hard on the slider, everything starts to flex and there goes a thousandth or two. . .

Gordon B. Clarke said:

From what I'm reading I can can certainly understand why the US is losing market share in global industry.

Click to expand...

Read as you want off the net.....You have not been to one of my shops.....don't count the US out yet.
Some of us view Toyota and Mits as behind the curve now.

Gordon B. Clarke said:

My suggestion would be that you learn how to measure. What you've written isn't only just stupid but suggests that maybe you should find a new line of work.

I get you don't know how to use a caliper so don't offer advice on it.

Click to expand...

Lol yeah I have no clue how to use them...no one here does I guess. I'll admit, over all these years the amount of retarded douchery you spew has never wained...Bravo on being a dick all the time!

car2 said:

Mr. Clarke can't even resist whatever compulsion he has (please see a therapist) to interject his incessant, tiresome, US-denigrating on a completely unrelated topic (please stick to your well-labelled political threads, such that your trolling drivel is easy to spot and ignore), and please STAY in Denmark.

Click to expand...

Nah let him come here for a few days...he needs a good ol American asswhooping.

QT: [Quite a bit has changed in the past 60 years. Maybe about time you moved into this century.]

Don't think you will find many grinder hands doing close round gauges with trusting a dial caliper.

plastikdreams said:

Lol yeah I have no clue how to use them...no one here does I guess. I'll admit, over all these years the amount of retarded douchery you spew has never wained...Bravo on being a dick all the time!

Click to expand...

Since you know them well and how to use them can you show your measurement analysis R&R numbers?
Sort of a basic thing any shop should have and every machinist would know. One would obviously not post proprietary reports but just your 6-sigma limits?
Measurement Systems Analysis (MSA): AIAG: 978165342115: Amazon.com: Books
You do do at least this since you "know" your measuring?
Without a base understanding of this manual I'm afraid I do have to put you in the without a clue land as all my machine operators get trained in it as measuring and knowing the errors and what to trust is the first step to making stuff to a print.
Please do not tell me your process limits are the same as the customer print without concern for gauging error guardband. I thought that went away 20 years back.

I am not talking above Gordon's level but sadly I find this above way too many small shops.
I poop on Gordon regularly here so all that's fine but you had better know your chit in this world because he does.
Bob

CarbideBob said:

Since you know them well and how to use them can you show your measurement analysis R&R numbers?
Sort of a basic thing any shop should have and every machinist would know. One would obviously not post proprietary reports but just your 6-sigma limits?
Measurement Systems Analysis (MSA): AIAG: 978165342115: Amazon.com: Books
You do do at least this since you "know" your measuring?
Without a base understanding of this manual I'm afraid I do have to put you in the without a clue land as all my machine operators get trained in it as measuring and knowing the errors and what to trust is the first step to making stuff to a print.
Bob

Click to expand...

I'm a machinist not a metrologist, I have a metrology department at work that cal's the calipers and mics accordingly contact them the company is Zimmer Biomet in Parsippany nj...myself I test with joblocks at random length intervals...using calipers is not a hard concept to grasp, if you get your rocks off making people that work for you read a book, that's fine...personally I think it's dumb but I'm not you and vice versa, but what do I know I evidently don't know how to use a caliper...

plastikdreams said:

, if you get your rocks off making people that work for you read a book, that's fine...personally I think it's dumb

Click to expand...

None of my machinists read the book but they understand what is in it. My job is to train them in WCM not to make them read manuals.
They all participate in gauge R&Rs and get feedback from these tests.
Not sure your bosses have shared this info or involved you. This is different than outside gauge calib. It is you using the gauges on the floor.

Outside calibration is a nice pissing down your leg thing but only the actual use on the floor is what matters.
Parts pass and fail and get shipped to customers from the shop floor not in some clean room lab.
We give a shit about what is good going out the door so yes employees get a few lessons on gaugesm gauging errors and guardbands.
It is worth the time and effort invested.
Bob