Digital Calipers
Digital Calipers
(OP)
Can anyone recommend a model of digital calipers? Accuracy requried is 0.0005". I am finding online information is confusing resolution with accuracy and want to make sure I get the right tool the first time.
Thanks a million,
Rebecca
Thanks a million,
Rebecca





RE: Digital Calipers
ht
RE: Digital Calipers
RE: Digital Calipers
RE: Digital Calipers
Most of the big manufacturers produce decent digital calipers starting at around $100 and very rapidly escalating from there. You have to ask yourself what features you need, or do not need, and price accordingly.
Having acquired one,hide it, in the back of your box.
Then go to Harbor Freight and buy a $24.99 stainless digital caliper It's good to plus or minus 0.001" and give this to the scroungers who want to borrow your digital caliper. Whatever you do, do not, lend your good one out.
B.E.
RE: Digital Calipers
Haven't used this one but there are several on this page that state your required accuracy. Mitutoyo is a good instrument.
http:
RE: Digital Calipers
Berkshire - They will be kept well out of site and I will be only lending out the old Kincrome set haha
Thanks again for your responses
RE: Digital Calipers
This is not the joke thread, and they didn't get it.
RE: Digital Calipers
Note that you also have to pay extra, a lot, for a digital caliper that is water resistant, and less likely to lose its mind for a while after being sprayed with water- based coolant (which typically has wetting agents in it).
Mike Halloran
Pembroke Pines, FL, USA
RE: Digital Calipers
I did get a giggle thanks
RE: Digital Calipers
....where do you buy a VERNIER that's good for tenths ?
RE: Digital Calipers
We get battery life of about 1-1.5 years with that model. Great caliper though as long as you respect the plastic/thumbwheel.
RE: Digital Calipers
All the precision in the world doesn't help if you don't learn to hold the thing right.
RE: Digital Calipers
Micrometers, digital or vernier, are good for .0001". I regard calipers as good for .001". The digital readout might indicate .0005", but you should try it out on gauge blocks.
I strongly agree with TheTick about vernier tools. Nobody borrows mine. When I need them, they are in my desk drawer where they belong.
RE: Digital Calipers
You buy the vernier caliper and a BIG magnifying glass.
B.E.
RE: Digital Calipers
RE: Digital Calipers
RE: Digital Calipers
But, I have seen mechanics accidentally hit the hold button without realizing and take bad readings. Dead batteries is a pain. Dial caliper are almost as convenient as digital and no batteries.
RE: Digital Calipers
RE: Digital Calipers
Most of my measurements do not require such precision, but I use them anyway and then convert to the required accuracy. In my business, it's like measuring with a micrometer, marking with a crayon, and cutting with an axe.
RE: Digital Calipers
Russell Giuliano
RE: Digital Calipers
All calipers, even the Swiss ones, have an inherent parallax error because the jaw needs to slide. They contain backlash and tensioning mechanisms and all of that, but I have found that to be safe, you just can't trust them to anything finer than about 3/1000. My Browne & Sharpe and Etalon are both trustable to about a thou, but no human hands other than mine have ever touched them. (well, that are still living, anyway, LOL)
My funniest experience is when I witnessed a mechanic taking cylinder bore readings on an engine block with a dial calipers. Yes, a standard 6 inch dial caliper! I think the look on my face must have sent a chill down his spine because he immediately asked if there were a more accurate way of measuring. He now owns a nice set of telescoping gauges and the mics to go with them.
RE: Digital Calipers
Please check the datasheets for digital calipers, and you'll not find a manufacturer that specifies better tolerance than 0.03 mm.
That the readout shows you 0.01 mm is a different matter.
Benta.
RE: Digital Calipers
At my last machining job before graduating and moving into engineering, I had to watch the inspectors. They were so sloppy that good parts would get rejected just because they couldn't hold caliper properly. My "rework" consisted of a demonstration and lesson.
RE: Digital Calipers
It never changes does it? I have a friend who is a corrective action engineer for a well known aircraft company. This week that person had to deal with a bunch of rejected "good" parts because the bores had been measured with a digital caliper instead of a 3 point micrometer.
When they were measured with the right equipment, they were well within tolerance.
B.E.
RE: Digital Calipers
It all depends on how accurately you need to measure something but it is certainly a quick and easy way of getting a very near measurement, even if that is to find out if a piece around 5" needs a 4-5" mic or a 5-6" mic to measure it accurately.
RE: Digital Calipers
Is that the real sign of being a crusty?
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Digital Calipers
That aside today's machining methods have outpaced the ability to use simple and inexpensive measuring instruments on the shop floor. One thing we used for any run of parts requiring precision measurements, little tenths' we would always try to set up a comparison gauging process in lieu of a direct measurement.
I was most fortunate in about my 5th year of employment I got to attend a ten day metrology course. 5 days with an in house instructor, 5 days with outside instruction covering some theory, and new instruments and methods. I would strongly recommend that if a course, seminar, or even a demonstration dealing with metrology comes along take it.
Again I was quite fortunate in that the company readily provided the instruments required for very accurate measurements and a relative clean room for calibration.
A bit of information gleaned from that course that has stuck with me all these years is that there are 21 geometric shapes when using a two point measurement you can get the same dimension.
I also have around 30 spring calipers of all persuasion used by my father, grandfather, and uncle for precision machining, actually comparison.
RE: Digital Calipers
I took Metrology in college. It has proved useful.
I keep a metric/English tape measure in my briefcase. I keep losing my 6" pocket scales, but I have one at the moment. The 6" vernier, my 0-1" micrometer (with vernier scale) and my 0-25mm micrometer (also with vernier) live in my desk drawer. Since they are vernier rather than digital, they are in my drawer. Perhaps some of you work in places where people put stuff back when they are finished with them.
RE: Digital Calipers
In my previous post the 21 geometric shapes pertain to bores.
[b]drawoh/b],
Our two big shops used the brass token approach to getting anything checked out of tool crib back. As far as scales go I usually could sneak in an order for dozen at a time. I was real bad about cutting them down to rough align a Faulk coupling.
It just dawned on me that years ago when a new batch of machinists in training were given there first it would be to make a C Clap with a 1" throat. I guess that was to replace the 1" micrometer.
RE: Digital Calipers
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Digital Calipers
Given todays competitive environment, should you be loaning out poor measurement tools to people in your own company?
RE: Digital Calipers
Check the ISO 9000 std.
RE: Digital Calipers
Mike Halloran
Pembroke Pines, FL, USA
RE: Digital Calipers
RE: Digital Calipers
It seems that someone just cut them down to a new length, the only problem being they are now 1" too short.
Supposedly this was a digital readout that was in error.
TheTick,
I have a ten foot tape measure that is all white no numbers, how would it fit in the calibration scheme.
RE: Digital Calipers
Better, a sticker we once put on a broken pressure gage said "calibrated to measure: nothing, +/- infinity".
RE: Digital Calipers
This is all fair enough unless you just want to know the weight of a 125g object +/- 5g, in less than 2 weeks! I just brought my digital kitchen scales in and calibrated them myself with an old 1lb stamped weight. What do you know, the $20 scales were there within 2g!
Metal verniers for me every time and yes I do keep them near all the time and was trained how to use them.
A slightly inaccurate answer is often 1000% better than no answer at all.
RE: Digital Calipers
RE: Digital Calipers
I built a shed in my backyward last fall. I had problems with my tape measure which measures inches, feet and inches and millimeters. The feet and inches text is on the opposite side of the tick from the inch dimension, which caused me to measure a half in inch off, repeatedly.
And I was unable to find my lumber stretcher.
If I were serious about framing, I would get a tape measure calibrated only in feet and inches.
RE: Digital Calipers
I had a lot of fun with the blank tape on the job as every time a fitter would miss a measurement I would hand him the tape and grease pencil and tell him just to make one mark.
RE: Digital Calipers
So, be honest, who carries an appropriate measuring instrument with them most of the time?
Is that the real sign of being a crusty?
...---...---
I keep a (plastic) mm+in caliper in my cell phone holder with my LED flashlight for rough measurements, plus a 16 ft inch+mm tape measure on my belt. Sure, neither is calibrated, but when I need to confirm a bolt diameter, or explain to a Spanish worker overseas how long to make the scaffolding under the genrator, I don't need/want thousandths tolerances. In the tool room, there are calibrated devices, I want the millwrights to use them when appropriate, but my own are needed where I am, not back down a dozen ladders and across the road in the turbine building.
Sure, you can make inches and mm errors, but I NEVER want to make conversions in the field. So I always carry double reading tapes and rulers.
Also, in today's non-tech, poorly trained worker, never shop-disciplined and poorly union-trained as youngsters and helpers, I will not trust most vernier readings, but feel they are more likely to make less errors with a digital instrument. Sure, the "old guys" will read verniers correctly. But the youngsters can't nowdays.
In today's work, would I trust
RE: Digital Calipers
factory QC test shows its accuracy is +-.001' from 1-6' and .002 from 6-12, mostly stainless, except for the casing around the dial which is plastic, but only a cover, the housing with the gears is contained in stainless as well, so the plastic cover is more for style.
@racookpe: 32 is a youngster to someone who is 65, and it doesnt take a genius to use a vernier, dont squeeze hard, and find hold it square.
but as for the topic of the thread, if you need accuracy to tenths you can not use ANY vernier, not even brand new.
use a micrometer.
like that guy said vernier = very near.
just use a micrometer.
if its a small part, and you're pressed for cash, check this out
http
RE: Digital Calipers
RE: Digital Calipers
As far as batteries go, they last forever. I think Mitutoyo says the batteries are good for 3 years of use. I know mine have gone over a year of frequent use with no change of batteries.
The claim that the wheels break and things like that strikes me as odd. Calipers are an engineering tool, so treat them as such and they will last forever. If you treat them like a common tool (think hammer) they wont last you as long as you would hope.
Get a good pair, and learn how to use them.
RE: Digital Calipers