I have Mitutoyo digital calipers, the readout resolution is down to .0005" but accuracy is .001", which is plenty for my uses. To check them I have Starrett standards for my micrometers. When checking I use the standard closest to the expected measurement I'm checking. Much like using check weights for my beam scales.
Grading a Caliper
- Thread starter Rick Ratzlaff
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Retired shooter
Gold $$ Contributor
Jackie's comment is spot on!
Calipers are great for quick measurements within a thousandth or two. Good for short, or small diameters. Bigger diameters, or llonger length need 8 inch or 12 in calipers etc. Most use calipers , because they will get close measurements, in many different lengths, diameters, or depth. Replacing micrometers of different sizes.
Learned how to read Vernier calipers & 6 / 12 incn scales when I was 14 or so. Same way with standard micrometer. Along came dial calipers, never saw digital measuring equipment till aircraft work.. Only reason they had digital equipment was for the younger generations, that could not read standard micrometer or calipers.
Only reason for me today to have digital anything is I don't trust my " OLDER " eyes.
To all a good day!
Greg@wfcustom
Gold $$ Contributor
As Jackie points out above, calipers are not for "precision" measurement, depending on your definition.
I call them the "tape measure" of "precision" measurement. That said you have to decide what precision means to you and what level you require. To respond to the OP question, Mitutoyo for the vast majority of work and practice, practice, practice. As several posters have pointed out it is all about feel.
As a side note people throw around 10ths (.0001) on these sites like they have a clean room for reloading.
If you really think you are that good grab a quality gauge pin set have a buddy mix them up and hand them to you one at a time. Then measure each one with a quality micrometer.
The vast majority of you will quickly find out you aren't as good as you thought.
FWIW, My go to mic when I really feel I need the precision is a Browne and Sharp (TESA) manual mic that is checked with a gauge block before use. Don't use it often but it makes me warm and fuzzy knowing it's in the drawer.
YMMV
Greg
Rocketvapor
Gold $$ Contributor
I use a dial caliper for some measurements, like shoulder bump, case length but have gone to this for highly repetitive 0 to1 inch measurements
Bought one but gave it as a present, then bought another.
Bought one but gave it as a present, then bought another.
Retired shooter
Gold $$ Contributor
Fred Bohl
Gold $$ Contributor
Caliper Accuracy
Mitutoyo ABSOLUTE Digimatic
Note the accuracy of the caliper itself is limited to ±0.0010 and there will be additional error due to the fit and cleanliness of the attachments and due to the users technique. My son has been in the metrology business over 20 years including calibration of calipers and micrometers for many customers. He also trains customers employees in the use of measurement instruments. His considered opinion is that a regular practiced user might achieve ±0.001 resolution and ±0.002 accuracy while an occasional user might achieve ±0.002 resolution and ±0.003 accuracy for a caliper that is regularly serviced and calibrated (annually by current ISO standards).
Mitutoyo ABSOLUTE Digimatic
Note the accuracy of the caliper itself is limited to ±0.0010 and there will be additional error due to the fit and cleanliness of the attachments and due to the users technique. My son has been in the metrology business over 20 years including calibration of calipers and micrometers for many customers. He also trains customers employees in the use of measurement instruments. His considered opinion is that a regular practiced user might achieve ±0.001 resolution and ±0.002 accuracy while an occasional user might achieve ±0.002 resolution and ±0.003 accuracy for a caliper that is regularly serviced and calibrated (annually by current ISO standards).
dusterdave173
Silver $$ Contributor
NEIKO digital from Amazon $25 and I get 223 and 6BR ammo that has single digit ES and simply hammers---so...good enough.
durand mortenson
Gold $$ Contributor
Greg, I have one also. It isn't anymore accurate than my old Japanese one but it sure is pretty!
jackieschmidt
Gold $$ Contributor
In all of my rifle endeavors, the one time I take measuring to the “tenth” very seriously is in my bullet making.
In that, it is an absolute nessessity.
Retired shooter
Gold $$ Contributor
Jackie
Sir, your eyes are older than mine ( no disrespect sir). Much more machining time than me.! Just saying.
But trying to stay on O P request.
Is the I gaging digital micrometer, equivalent, to the Mitutoyo digital mic. Never been around I Gaging.
Basically we are all looking to get to a specific measurement, with what we assume to be reliable, and hopefully accurate measuring equipment.
To all a good day.
Sir, your eyes are older than mine ( no disrespect sir). Much more machining time than me.! Just saying.
But trying to stay on O P request.
Is the I gaging digital micrometer, equivalent, to the Mitutoyo digital mic. Never been around I Gaging.
Basically we are all looking to get to a specific measurement, with what we assume to be reliable, and hopefully accurate measuring equipment.
To all a good day.
A friend of mine wrote software for a proprietary wireless interface using the Mitsutoyo SPC port. What he found out with most of the import calipers is that they will eat the batteries up quickly if you don't turn them off, unlike the Mitsutoyo. This was about 10 years ago and the patent agency wouldn't issue him a patent, saying it was too vague.
I pretty much only use Mitsutoyo calipers, they just don't cost very much and are the gold standard pretty much. There are better calipers if you have deep pockets, which I don't. I tried to sell it to Lee Valley, but Rob Lee wasn't interested. Here it is being used on a lathe.
DISCLAIMER: I know I spelled Mitutoyo as Mitsutoyo, because that is the proper pronounciation and spelling in Japan.
I pretty much only use Mitsutoyo calipers, they just don't cost very much and are the gold standard pretty much. There are better calipers if you have deep pockets, which I don't. I tried to sell it to Lee Valley, but Rob Lee wasn't interested. Here it is being used on a lathe.
DISCLAIMER: I know I spelled Mitutoyo as Mitsutoyo, because that is the proper pronounciation and spelling in Japan.
Retired shooter
Gold $$ Contributor
Understand,
you get what ,you pay for. ! Just don't want to buy green paint, when red might be as good !
you get what ,you pay for. ! Just don't want to buy green paint, when red might be as good !
Retired shooter
Gold $$ Contributor
Would not know what to do w8th your modern lathe.
Rocketvapor
Gold $$ Contributor
Seems everyone is taking the +/- 0.001" caliper tolerance as gospel.
That's an acceptance limit for the instrument, over the entire range.
That doesn't mean the instrument can't make BETTER measurements.
That also doesn't include sources of error like temperature, wear, dirt, or USER errors.
Surface condition of the test article can impact measurements in a shop/home environment.
For those that work in Metrology, if an instrument doesn't perform within specs it needs repair or replacement. If it performs better than spec, it's acceptable.
I've personally seen Dial Calipers in a controlled environment that measured BETTER than one division on any standard thrown at it. I called them good and put my stamp on the sticker.
Try the pin set on the towel experiment, see for your self.
If that is too much, try a few pins, like .222", .223", 224", .225" and mix them up and measure one of them (without cheating by looking at the engraved size) 10 times.
Record the readings, estimating to a FRACTION of a division. Like .2241, .2244, .2242, etc.
For those of you that use a 55 grain bullet as your check weight, why not also use it as your diameter check standard
That's an acceptance limit for the instrument, over the entire range.
That doesn't mean the instrument can't make BETTER measurements.
That also doesn't include sources of error like temperature, wear, dirt, or USER errors.
Surface condition of the test article can impact measurements in a shop/home environment.
For those that work in Metrology, if an instrument doesn't perform within specs it needs repair or replacement. If it performs better than spec, it's acceptable.
I've personally seen Dial Calipers in a controlled environment that measured BETTER than one division on any standard thrown at it. I called them good and put my stamp on the sticker.
Try the pin set on the towel experiment, see for your self.
If that is too much, try a few pins, like .222", .223", 224", .225" and mix them up and measure one of them (without cheating by looking at the engraved size) 10 times.
Record the readings, estimating to a FRACTION of a division. Like .2241, .2244, .2242, etc.
For those of you that use a 55 grain bullet as your check weight, why not also use it as your diameter check standard
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Rocketvapor
Gold $$ Contributor
Calipers are still my go to for case length, datum, and CBTO measurements as the case head and neck diameters of most cases are larger than most micrometer anvils.
Lucky Shooter
Gold $$ Contributor
My eyes are old and I sometimes have the .025" syndrome when using micrometers.
I find that the caliper quickly gets me into the ball park for a micrometer measurement.
I have an old inexpensive Frankfort Arsenal Dial from Midway. It has a clean uncluttered face
and has been about as accurate as I'd expect for a caliper.
I'll possibly buy a better one some day but this oldie el-cheapo has been good for a long
time.
A. Weldy
I find that the caliper quickly gets me into the ball park for a micrometer measurement.
I have an old inexpensive Frankfort Arsenal Dial from Midway. It has a clean uncluttered face
and has been about as accurate as I'd expect for a caliper.
I'll possibly buy a better one some day but this oldie el-cheapo has been good for a long
time.
A. Weldy
Vernier are great tools. Durable and they really teach the user about scale and accuracy by the way they function. A way more reliable tool than a digital or dial instrument100%
Although there are significant quality variations in what we can source today.
Some 50 yrs ago pop gave me a set on 6"/150mm Kanon calipers and today they are still some of the best I have used albeit they only had a vernier scale.
What sets them above others is the thumbwheel allowing for better 'feel' to provide repeatable measurements.
I use a micrometer to confirm the accuracy of a caliper, I'll use a pin gauge as the reference. Repeatability is self-evident, the key is to always measure the same thing each time. Technique is important; micrometers have either ratchet or friction thimbles so the each measurement has the same amount of torque applied to the spindle, calipers require a bit more feel judgement. Cleanliness is also important, more so as resolution increases.
I've got one caliper which has 4 decimal places, 0.0000, the other has 3 decimal places, 0.000. The first one cannot indicate 0.0001, nor 0.0007 but, if the last digit is a 5, it's closer to the next thousandths, if it's 0, it's closer to the nominal thousandths.
Hope that helps.
Fast14riot
Gold $$ Contributor
I have a cheap dial caliper that I use pretty much only for sorting because a needle is much faster to see variation rather than absolute measurement. But, I still use a pair of Mitutoyo vernier .001" for measuring. Etalon, Fowler and Starrett mics when I need to know what size something really is.
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