Lesson Learned: Electronic Calipers

[Southron Sanders]

I was getting ready to load some cast .45 Colt bullets a friend gave me and to be prudent, I used my electronic calipers to measure the bullet diameter BEFORE I started the loading process.

According to my "Trusty" Electronic Caliper-THE BULLET WAS UNDERSIZE!!!

Figuring that somehow I had "botched" the measuring process-I measured another bullet from the batch, and it too was way undersize.

Then an idea struck me.

To quote General Buck Turginson (played by actor George C. Scott in the movie: "Dr. Strangelove.")

"I smell a BIG, FAT, COMMIE RAT!!!"

I then measured the bullets in question with my old fashioned, American made, non-electronic, micrometer.

The mike confirmed that the bullets were of the right diameter.

My electronic caliper had gone "Whacky" on me.

(I have had it for three years and until now, it has been trustworthy.)

Will a new battery restore it to its youthful accuracy-or should I send it on a permanent vacation?

[Yeah, yeah, yeah, I know they don't cost much at Harbor Freight, but I am basically cheap and hate to spend money!]

INQUIRING MINDS WANT TO KNOW

THANKS!!!!

[MBTcustom]

New batteries are always a good idea, but proper use is probably more what's needed in this case.
Take your calipers and close them on a piece of clean printer paper. Without pinching, pull the paper from between the blades. This cleans them. Open them half an inch or so and slide them shut using the same pressure that you would to measure an object. Zero the digital. Open them and close them several times to make sure they always return to zero.

One big mistake that lots of people make with calipers (and I'm not accusing you of anything here) is that they substitute pressure for feel. Calipers are all about the "feel". It takes a gentile touch and hardly any pressure. Some folks measure something by snapping the calipers on the object and smooshing the living $hit out of it. Brand new calipers will allow you to get away with this type of abuse, but If you make it a habit, they will eventually get sprung. A sprung set of calipers will read zero every time but will always give undersized readings when measuring an object. If this sounds all too familiar, pitch 'em and learn a hard lesson.
I am a career toolmaker and so far I have used up 1 set of calipers, but my instructor in college showed me his 50 year old set and they were still pristine.
Try those tips and good luck.

[Jim_Fleming]

Very likely the battery change will solve the problem.

Also be sure to wipe the measuring jaws off until they're very clean, close up your calipers, then hit the zero button.

This should bring them back calibration.

Sent from my Droid

[trk]

Having a standard to measure against is also good. Check zero when closed, measure the standard. Both readings MUST be repeatable or something needs to be fixed - instrument or operator.

[Cap'n Morgan]

It depends on your needs, but cheap electronic measuring instruments can be a disaster in a machine shop. I would prefer analog measuring instruments to electronic ones whenever it comes to cheap Chinese c..p!

Whatever you do stay the hell away from anything made by a company named "Insize". We got one of their cheap micrometers which would shift zero during use. Luckily we noticed the error before anything happend. We were not so lucky with the replacement and scrapped a bunch of parts. We also got an Insize caliper for testing in our shop - nice big display and everything. The display would switch off after a few minutes not in use, probably to save battery, but when woken up the caliber would be off exactly a 1/10 of an inch ever so often. My boss twisted it into a knot after the incident with the micrometer.

A failure rate of three out of three - from now on It's Mitutoyo or Tesa... Buy quality - cry once!

[Calamity Jake]

On top of the calipers there should be 2 small adjusting screws, there used to take up any slack or looseness in the gibs, try turning the screws in until there snug then back off about 1/16 turn. The amount of tension needs to be the same on both screws.

[theperfessor]

I won't have an electronic caliper in my shop. Ever. Every time I need one the batteries always seem to be dead. My old Craftsman vernier calipers still work fine, every time.

[joesig]

Electronic calipers can "slip" if you open or close them too quickly. I agree with the perfessor, my grandfather's calipers from the '30's have yet to have the batteries changed! Bifocal safety glasses make it easier to read now than my younger days.

[adrians]

having read all posts here in this thread i'm going to put my cheap digital set in a drawer and forget about them (i'm always zeroing them even after cleaning the jaw flats ,) .
i have been meaning to buy a new dial set for months now and you all have motivated me to go out today and grab a set ,,,,,thank you all for making up my mind for me .
yall have a great day .adrian,

[DCM]

Southern Sanders personally I would replace the battery, and clean the calipers to see what happens.

For my personal use if something NEEDS to be precise I use a non electronic micrometer after checking it against my standards.

I own a Mititoyo digital caliper that is cery fast and very accurate when checked against my standards which I use regularly, but when it comes down to brass tacks I still double check it with a non electronic.

With all that said my son wanted a digital caliper of his own so I bought him a cheapo from the local home center and was quite surprised how accurate it is with a new battery in it. I still would not trust it for truly precision work, but it is plenty accurate for most tasks and cost WAY less than my Mititoyo.

[dragonrider]

I use a set of digital calipers for quick work, never when I want to be absolutely sure of a measurement. But I will trust the digital more than a "dial" type caliper. Dial calipers are the worst for skipping a gear when you open them up and most times you don't feel it happen and presto your measurement is off. Verier calipers and micrometer are the ones to use. Digital are easy to read and can be use by anyone but the chances of bad readings are almost guaranteed, especially for rookie. I do not recommend that anyone use digital or dial calipers, if you have never used vernier calipers or micrometers before get them and learn, it is not that hard. Might take all of five minutes.

[Jim_Fleming]

I have had my dial calipers slip a tooth at the least unexpected moment.

I like my digital calipers because of precision and speed. I have never had the least bit of trouble with my digital calipers.

I own both, they both have pros they both have cons.

Digital at home, dial at work.

Sent from my Droid

[Sonnypie]

Bought once, never cried....
I bought Starrett 721 digital calipers when I needed them.
They are Certified by Starrett to be accurate.
I was proofing tolerances on a product. I had to be "right".
Mine has a slide off battery compartment that makes it real easy to turn it off. I merely slide it over enough to disconnect it. Then they are ready to go anytime.
I always wipe them down and store in the original case with the calipers slightly open.

How a tool, especially a precision tool, is taken care of can have a lot to do with what it gives back.

I also have Starrett Micrometers for back ups. But they are old and of questionable accuracy.
Any of them can be checked against things like feeler gauges to see what you get with them and to train your fingers.

[geargnasher]

Bought once, never cried....
I bought Starrett 721 digital calipers when I needed them.
They are Certified by Starrett to be accurate.
I was proofing tolerances on a product. I had to be "right".
Mine has a slide off battery compartment that makes it real easy to turn it off. I merely slide it over enough to disconnect it. Then they are ready to go anytime.
I always wipe them down and store in the original case with the calipers slightly open.

How a tool, especially a precision tool, is taken care of can have a lot to do with what it gives back.

I also have Starrett Micrometers for back ups. But they are old and of questionable accuracy.
Any of them can be checked against things like feeler gauges to see what you get with them and to train your fingers.

I own a quality set of digital calipers, and they have been accurate and reliable for some stuff, like in the wood shop. HOWEVER, I use micrometers for everything both at work (Mitutoyo) and in the reloading room (Fowler). Six piece set gets you from zero to six inches, and each comes with a calibration rod.

Gear

[Mal Paso]

I have a $20 Harbor Freight Dial Caliper ( and 8 Micrometers ). I have had the HF Caliper for at least 6 years, it has never skipped a tooth and is quite accurate. I was going to brag but can't find my Standards. TMS

[Sonnypie]

I own a quality set of digital calipers, and they have been accurate and reliable for some stuff, like in the wood shop. HOWEVER, I use micrometers for everything both at work (Mitutoyo) and in the reloading room (Fowler). Six piece set gets you from zero to six inches, and each comes with a calibration rod.

Gear

I think I will choose to ignore that.
Apparently you do not know what extents it takes to achieve accuracy in woodworking equipment.
I also machine and weld and fabricate.
That's it, I'm out of pee.

[303Guy]

... but cheap electronic measuring instruments can be a disaster in a machine shop ...

True but they are quick and useful for getting some idea of dimensions. Always check their repeatability and jaw parallel and of course, clean the jaws before checking zero. Very accurate measurements can be taken with digital calipers, even cheapo ones. But relying them for precision work is a bit dodgy!

If they suddenly under-read there is a good chance something is preventing proper zero. Dirt between the jaws or loose slide screws for example. If a low battery causes loss of accuracy then toss the thing! A low battery should do no more than blink the display or fade.

P.S. Sonnypie, that was funny!

[HORNET]

I usually use the electronic calipers at work and the dial ones at home. Stinking batteries tend to be dead when I need them and I'd rather let the company buy them...
For precision stuff I use micrometers with the vernier scale, no batteries, no digital readout to get wonky.

[Sonnypie]

P.S. Sonnypie, that was funny!

Glad to make you laugh. :takinWiz:
I do use both, digital and analog.
And the batteries do seem to last forever in the analog ones.

I found a really good way to use one of my analog ones over here.
See post #10.

I'm late for my hot furnace... 'Scuse me.
(I'll be back when it gets hot in the shop.)

[cbrick]

Something like 20-25 years ago I bought the best Mitutoyo digital micrometer and calipers as a set. They came with a .500 standard and to this day they are spot on. I last checked the micrometer a couple of weeks ago and it read .00002" on the half inch standard, close enough for me.

Batteries? Replaced maybe twice since I've had them. Paper work that came with the set said that batteries should last one year when used in a shop 8 hours a day, 5 days a week.

Precision work? I have full confidence in these tools, with that said I never use the calipers for precision work. If it's something that I want or need to know closer than .001" I use the micrometer. Calipers aren't designed to be as precise as a micrometer, that's why they make both. Cartridge case length, cartridge over all length etc calipers are just the ticket. When I need to know the diameter of a bullet (or anything else) it's the micrometer. Use the correct tool for the job.

Rick