Calipers, dial or digital?

Scotty454 said:
Also, I LOL'd pretty good about measuring reliably to a tenth of a tenth (A hundred thousandth) with ANYTHING by hand. Even measuring repeatably to a tenth is a stretch. Sub tenth accuracy is temperature/humidity controlled room territory.
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Mitutoyo MDH-25M. Yes, you have to be careful with temp (and the mikes), but not obsessive. Humidity, unless you are using them underwater, now I am LOL! Actually, thinking about it, they would probably work under water if it was pretty shallow. I don't think the technician responsible for all the procurement and maintenance of all the myriad of measuring tools and devices would be too happy if I tried that though. - Just checked, they re not IP65 or better so they have to stay dry.
 
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One day when I start re-investing into high precision measuring tools I will get one of the Mitutoyo with the data logging feature, would make life so much easier. Right now I'm using a set of CT specials and its been pretty good. I prefer digital because it tells me what I need to know right away.
 
Well I made up my mind and ordered another digital one, an igaging absolute origin. Lots of positive reviews online so hope this one will last longer.
The dust sensitivity of dail (yes, im not one of those people with a garage/shop that looks like a cleanroom) and quick/easy readout of digital was what sealed the deal for me.
 
rick357 said:
Mitutoyo MDH-25M. Yes, you have to be careful with temp (and the mikes), but not obsessive. Humidity, unless you are using them underwater, now I am LOL! Actually, thinking about it, they would probably work under water if it was pretty shallow. I don't think the technician responsible for all the procurement and maintenance of all the myriad of measuring tools and devices would be too happy if I tried that though. - Just checked, they re not IP65 or better so they have to stay dry.
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Have you ever actually used one of those?? The human hand is just not cable of holding something steadily enough, and repeating motions accurately enough to get that kind of accuracy out of a hand held tool. It just can't be done. You can put millionth resolution on a mic, but that doesn't mean a human will be able to use it effectively to that level of accuracy. There's far too many variables. If the amount of friction in the thimble changes AT ALL, your measurement is junk (Which happens). I have used the 5 decimal Mitutoyo mics, and I just wouldn't rely on them to their smallest graduation. Call it what you will.

Unless you're some kind of super human than can measure as accurately as a half million dollar Zeiss CMM with a mic, hundred thousandth accuracy by hand is just a little unrealistic.
 
I have 2 sets of Mitutoyo digital calipers at my reloading bench.
These are plenty accurate to measure case length, and to compare
bullet diameters quickly. For more accurate measurement, I use
a digital micrometer that reads to .00005" It detects subtle differences
in bullet lots [read diameters] and other things that are missed
by less accurate measuring devices. Case head expansion, for example.
It pays to buy quality tools...buy once, cry once, lol. Dave.
 
Scotty454 said:
Have you ever actually used one of those?? The human hand is just not cable of holding something steadily enough, and repeating motions accurately enough to get that kind of accuracy out of a hand held tool. It just can't be done. You can put millionth resolution on a mic, but that doesn't mean a human will be able to use it effectively to that level of accuracy. There's far too many variables. If the amount of friction in the thimble changes AT ALL, your measurement is junk (Which happens). I have used the 5 decimal Mitutoyo mics, and I just wouldn't rely on them to their smallest graduation. Call it what you will.

Unless you're some kind of super human than can measure as accurately as a half million dollar Zeiss CMM with a mic, hundred thousandth accuracy by hand is just a little unrealistic.
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Yes amazingly enough, some humans can and do such. Operating such crude devices repeatedly and reliably on the terms of what they do every day would be dismissive. I marvel at what some humans are truly capable of - hand made swiss watches - surgeons operating on the most delicate of structures immediately come to mind.

And, as with most everything that gets built or processed, garbage in = garbage out. That is why there are a few people involved who's sole job is to procure and ensure all the measurement devices are maintained, tested on schedules for proper operation, and calibration traceable back to the applicable NIST/NRC standards. They document quite literally everything. Every time some of the most delicate items are used, they are calibrated both before and after use. These micrometers are part of that group of instruments. When you are doing certain things for certain entities, the process is paramount. The procedures used and results must be to standards and fully trackable.

None of that is in any way required to measure COAL or CBTO however. A simple inexpensive caliper is more than sufficient. If you are wanting finer measurements like case web or neck diameters then I would still suggest one of the Mitutoyo micrometers or similar caliber devices.
 
Give ten people a micrometer with one millionths discrimination, and you’ll get twenty different measurements of the same diameter if you let each one try it twice.
 
Our most accurate measurement system at work has a load cell system to automatically take a measurement when the specific pressure is reached.

The machine itself is verified to +\-0.000034".

That's outside of reloading though lol. That system was $29000
 
Scotty454 said:
This is my biggest issue with a dial caliper. If junk gets in the rack, it can cause the dial gear to skip a tooth and throw your measurement off. Also, cheap dial calipers are about as useful as hammers as they are as calipers. I use mine to scribe lines on parts. Lol the zero has rotated around the dial at least once already.

The cheap-o digital calipers are actually not too bad for OD measurements, if you're familiar with using them and can apply even pressure. The gritty slide makes it a little more difficult, but the scales are fairly accurate. I wouldn't trust them as far as I could throw them for inside measurements though. Even my $600 Mitutoyo set is questionable for ID sizes. Pretty much reference only.

Also, I LOL'd pretty good about measuring reliably to a tenth of a tenth (A hundred thousandth) with ANYTHING by hand. Even measuring repeatably to a tenth is a stretch. Sub tenth accuracy is temperature/humidity controlled room territory.
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While generally, I agree; I do have a "Canadian Tire" one in my rough and tumble tool box at work as well as my top end Mitutoyo when precision matters. They and my dial caliper are celebrated every year by our metrologist.

Calipers are limited. At work we also have optical measurement equipment, a CMM and a Faro arm (in a climate controlled lab), as well as micrometers, and a bunch of other indicators; all have their place; none are good for everything.
 
BlackSheepBrass said:
Dial calipers are my preferred method. I keep "inexpensive" digitals calipers all over the shop for my employees to use. I keep certified dial calipers in my desk and when I go out onto the floor to do my checks, I check my measurements against the quality control sheets to see how everything lines up.

I actually use Insize branded calipers. They hold the same certification as the Mitutoyo and Starrett, They can be sent back for calibration. My local industrial support store sells them at a rate of 10:1 of the other brands. They are significantly less expensive ($70 - $80 a piece). I just buy 6 of them at a time and at the end of a year I give them to my employees and replace them.
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Being certified to various standards, and having two Metrologists on staff, everyone on the floor has certified calipers. We use some insize, and they are great, but we have found that the Mitutoyo stand up better long term. Our previous metrologist kept all the old buggered parts and calipers, and would rebuild and re-certify with his stash of parts.
 
bertn said:
Well I made up my mind and ordered another digital one, an igaging absolute origin. Lots of positive reviews online so hope this one will last longer.
The dust sensitivity of dail (yes, im not one of those people with a garage/shop that looks like a cleanroom) and quick/easy readout of digital was what sealed the deal for me.
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Absolute are good, and can be calibrated year after year as well. A couple of the other engineers have them, and like them!
 
100% Starrett Dial for accuracy, ease of use, and reliability! never need a battery. Have had one in my toolbox for going on 20yrs now, and it's never let me down.
 
I have both. All high quality. I bought the digital first because I could measure Imperial and metric. Batteries can be a drag. Dials are my go to these days. If you are patient you can find good deals on Kiritimati in your locale. Quality is a must regardless!
 
You can go 3-5yrs with a mitutoyo before the battery goes dead. Eventually the screen will start to dim a bit as the battery gets weaker and the B lights up, still goes a long time from there on. I have a dozen of them left on 24/7.
Buy good energizer 357 batteries. Pack of 3 is $10.
 
At 15 bucks the CT cheapie is hard to beat. I have two and use them most of the time. Also a mitutoyo dial that is used sparingly, more as a check on the CT calipers and backup when batteries go dead. But for anything critical i dont use calipers.
 
I've seen the CT digital caliper go on sale to $7-8 and even then I wouldn't recommend it. The construction is cheap and even when the jaws are closed you have to squeeze them to get a 0 reading.

If you're using a caliper, you obviously need precision, so might as well get a quality one.
 
Mechanical over digital if precision and repeatability matter to you. So you may have to learn to read a vernier scale, bonus!
 
In post 25 I stated I liked digital calipers because of the big numbers that are easy to see for old farts.

I'm glad there are so many younger people here that ate their carrots and have good vision and can read a dial caliper.

"BUT" this posting should be divided into a old fart section and a young carrot eating section.

And remember old smart people keep spare batteries for their calipers, hearing aids and pacemakers. ;)
 
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