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Dial Caliper measurements

I will defiantly get a few gage blocks and just start measuring them and find a technique that good for me, but right at the same time. Thank you everyone!
 
One caliper can replace three different types of micrometers and is reliable to whatever you have proven it good to, hopefully with gauge blocks. I know my digital caliper reads true to tenths in the one inch range but I haven't tested it further than one inch. Once I get within a thousandth or two I'll get out the micrometer. If you don't use calipers, you're not being as efficient as possible. Start using them

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One caliper can replace three different types of micrometers and is reliable to whatever you have proven it good to, hopefully with gauge blocks..,,,,,,,,,,,,,

Which is all great if the parts you are machining are flat and square under a micron like a gauge block, otherwise.....real parts and that is where the rubber hits the road.
Only a rookie works with gauge blocks which is why you have gold, silver, and working masters.
Perhaps my world is way different as 50,000 parts must fit 50,000 others from the other side of the earth or oh-shit somebody is gonna get fired.
Be assured, managers and supervisors get kicked to the road here for a defect on the line.
Bob
 
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. . .

Sounds like you're either using an old caliper or one with too much slack in the sliding jaw. You also must have very impressive hands if you can measure something over 6" using that method,

Digital Caliper Accuracy - YouTube

Every measurement on display in that video is in mm. One of the calipers has a display of 0.005mm (0.0002") and yes, I know that doesn't mean it is accurate to that number. It is though slightly more accurate than a standard digital caliper.
 
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.

Of course there are good places in the USA but as long machinists are expected to supply their own tools in many places many will sag behind.
 
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!

I don't know about "no one here" but you certainly don't and with that I hope I never need to comment anything you post again. You are a disgrace to the profession.
 
The OP was about "using a dial caliper" so I don't know why micrometers got into the fray :)

What should be used to measure should depend on the accuracy necessary. The 10Xrule should be remembered. Forgetting for a minute that micrometers are much more accurate than calipers then pause and think how many external and internal micrometers it'd take to replace just one 6" caliper.

If a caliper is good enough to do the job it'd be daft to use a micrometer.

As I've already written in this thread I've been to several of the companies that make and their dealers that sell measuring equipment and not just Chinese ones. Mitutoyo, Tesa, Mahr, Sylvac, VIS etc. and I've seen how they use and test calipers yet a couple of you seem to think you know more than those that make and sell them. At an exhibition in Germany I measured together with the Mitutoyo leader of Mitutoyo in Europe and we not only used and held the calipers the same way but we also got the same results.

As I've also written :) - this could be a lengthy thread.
 
Which is all great if the parts you are machining are flat and square under a micron like a gauge block, otherwise.....real parts and that is where the rubber hits the road.
Only a rookie works with gauge blocks which is why you have gold, silver, and working masters.
Perhaps my world is way different as 50,000 parts must fit 50,000 others from the other side of the earth or oh-shit somebody is gonna get fired.
Be assured, managers and supervisors get kicked to the road here for a defect on the line.
Bob

I've mentioned this in another thread long ago but that only gauge blocks get used for caliper calibration surprises me. For depth and step measurement then yes.

Personally I like to use a small diameter ground cylinder and this is best to determine how much wear, if any, there is on the caliper jaws. Measure as close to the beam, equidistant from the beam and then on the "sharp" ends. Max difference shouldn't be more than 0.01mm.

As to calibrating the jaws for internal measurement then use a ring gauge around 5mm to 1/4". Allow an extra 0.02mm inaccuracy as to be exact it'd require that the jaws were knife sharp and thus wear rapidly.

I wasn't born with this knowledge. I learned by watching and talking to experts :)
 
Some interesting language used here, hope the OP doesn’t get disabused to using calipers in the shop… Like bookeeping (follows rules of accounting) this shit follows rules also so just be mindful of that. The bit about things changing over 60 years... Correct me if I'm wrong but the growth of materials with temperature hasn't changed that I know of, and because of the way calipers are often handled (much of one or both hands on the beam until final measure), they can be a problem in continuous use.

I would teach (with any tool like this) you audit yourself by measuring without looking at the dial/readout when adjusting the tool. Then, when you bring your eyes to the result and it repeats over and over on the same part → you’re pretty much there.

The comment about old timers & slapping calipers out of somebody’s hands is “deft” not “daft”. In personal context it was more a concern of someone “running with scissors” rather than any disdain for calipers in particular. With inspection in particular it is easy to check a bunch of +/- .002” dimensions over a number of parts with calipers. But when you (conveniently) hold the caliper in one hand while reporting the result on paper and this goes on for a period of time → you have “broken a hard learned rule”. It doesn’t matter how little the gage has grown, you won’t pass a true audit for quality inspection. The same is true for jo-blocks, mics & go/no-go gages also, you just follow the rules for handling the tool & you’ll be good.

Good Luck,
Matt
 
I maintain the quality and condition of the device and the skill of the operator are important.
Take 8 people with 1 to 5 years experience. Provide 8 dial calipers ranging from $7.98 to $ 398 that range from brand new to two years old. Have these guys measure three perfect round disk gauges perhaps .12973, 1.5652 and 1.63572" to write down the findings and I bet you would see near .001 and perhaps more variation higest to lowest. So measuring a + or - .001 disk and shipping the part would be borderline.
Still they are very handy and accurate. I use them often...But For the best very close measure most hand measuring devices are used as a compararator such as to a jo block stack. At least measure something (a master)perhaps once in a while to see ones feel is decent.
Measuring round is the most difficult as in a production application measuring the same size hundreds of times a day calipers may be likely to wear in one spot so not checking to a master once in a while would not be logical. Checking with gauge blocks is not always best for devices that must check round.

IMHO
 
If the tolerance is ±0.001 then of course a micrometer should be used in preference to a caliper.
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most machinist agree micrometer is more repeatable and accurate. what i find is i check inside mic to outside mic and it is common to get a .0005" or even .001" difference. well known hold a inside mic in you hand too long and it changes length from the heat of your hand. bigger measurements than 6" is harder to do compared to little parts as anybody with a lot of experience will tell you
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i prefer a indicating gage set to gage blocks when i want to accurately read to less than .001" and i use gloves or more to keep the heat of my hands from effecting measuring gage
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Gordon sells caliper attachments ?? so his saying he prefers to use calipers is partially based on him wanting to sell stuff perhaps. i find a lot of postings are just subtle people trying to sell stuff.
 

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I'll keep my comments to digital calipers as I as good as never use any other type of caliper.

If used for what it is intended for, then I've never seen a handier or more versatile measuring device.

As to accuracy then I hope most realise that what is shown on the display isn't always the correct measurement. Calipers have an inaccuracy allowance as do all measuring instruments. This inaccuracy is fairly easy to find simply by measuring a known dimension.

The quality of any measuring device is almost always crucial and I've seen digital calipers on sale at stores for as little as $5. Using these in a shop would be, to put it diplomatically, be foolhardy. I've never seen a rule of thumb applied to digital calipers but my advice would be that if they cost less than $50 I'd think twice before buying.

Skill is of course also important and finding what the user considers a suitable measurement pressure to obtain consistent, repetitive results is crucial. For a digital caliper of up to 8" I try and use as close to 4 - 5N as possible. I've also found that pushing the sliding jaw on a Mitutoyo tends to require just a bit more force than with most others. I doubt though if it's more than 1N.

Something many tend to either forget or overlook is that the smallest amount of oil on the top and bottom of the beam, and then wiped off, makes a remarkable difference to reducing the sliding friction. Almost like getting a new caliper.

Reading the posts some obviously don't like calipers and this could be because of one or more of several reasons.
1. They haven't tried a caliper less than 10 years old.
2. What they need to measure has a tolerance beyond the capability of a caliper
3. They don't know how to use one correctly and have never been shown how.

I hope no one gets forced into measuring with a caliper if they don't want to and I'll never understand why some seem to get so worked up over what is a simple device. I've long since lost count of the types and brands I've handled and it's been a while since I held one I'd describe as useless or rubbish. Even a cheap one is OK as long as it gets remembered that it's cheap for a reason.
 
I maintain the quality of the device and the skill of the operator are important.
Take 8 people with 1 to 5 years experience. Provide 8 dial calipers ranging from $7.98 to $ 398 that range from brand new to two years old. Have these guys measure three perfect round disk gauges perhaps .12973, 1.5652 and 1.63572" to write down the findings and I bet you would see near .001 and perhaps more variation higest to lowest. So measuring a + or - .001 disk and shipping the part would be borderline.
Still they are very handy and accurate. I use them often...But For the best very close measure most hand measuring devices are used as a compararator such as to a jo block stack. At least measure something (a master)perhaps once in a while to see ones feel is decent.
Measuring round is the most difficult as in a production application measuring the same size hundreds of times a day calipers may be likely to wear in one spot so not checking to a master once in a while would not be logical.

IMHO
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measuring round is hard to do as well as when you read a certain level you start to pick up out of round or lobing. obviously on a mill circular milling you expect some out of roundness but even on a lathe it is not unheard of to get roundness variations. sometimes vibration caused or machine related or hardness variations or servo oscillation or many factors.
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where i work fairly standard to read minimum and maximum size and write down both. very annoying when bore is out of round .0002" and you put 2 parts together weighing 200 lbs or much more and they will not rotate or rotates partial revolution and the 2 out of round parts lock up before a full rotation.
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then theirs taper or size variation along the length of a bore or OD of a part. see that every day. again i usually read minimum and max sizes looking for taper and out of round. obviously a cutter can wear .0001" or more cutting 10", i see that too every day.
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lobing out of roundness - Google Search
 
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Gordon sells caliper attachments ?? so his saying he prefers to use calipers is partially based on him wanting to sell stuff perhaps. i find a lot of postings are just subtle people trying to sell stuff.

Huh? I've never said I prefer using calipers. I use what the item and dimension dictates is most suitable.

I also sell calipers and other measuring instruments so that's one reason I know a bit about them. Another is that I've worked as QC manager for over 25 years before starting my own business.

Are you saying that just because someone is professionally involved that they shouldn't give advice?
Would a Mitutoyo employee be told he mustn't mention Mitutoyo if he posted?

I'm giving advice that can be taken or ignored. I'm pretty sure I've never recommended one brand as being better than another.

What you're introducing into this thread has nothing to do with the OP. Maybe a new thread?
 
I have no doubt Gordon’s measuring devices are good quality even though I have not used them.

His caliper pressure regulating device and the clutch device found on many micrometers give credence that operator skill is important. A heavy handed guy might crank down harder than a lady or light handed guy with depending on feel alone, and never feeling to a gauge master. Dial micrometers have a pressure control and are best used comparing to a jo block stack, so reducing the need for feel..

The inspector at a tools provide shop might set a measuring tool for his feel and a guy out in the shop might feel it differently. So checking a jo block or gauge to see the measuring device along with one's feel checks the same is important IMHO. Yes dial and digital calipers are simply set to zero with hopefully the same pressure as the part check… and hopefully they are straight and true along the whole measure distance.

One journeyman as I was learning the trade said check with not looking, then look to see you are correct to the master. Feel the part with coming in, then rub across the part to see the size and feel the rub. Then rub in a few places to see the same feel to check for round. Always thought that was good for checking tenths and microns with the older measuring devices.... and to see the clutch device on modern tools proves same size as the master.

*To the op I would say check in a few places along the jaws for rounds and when the check varies out of needed spec the device may need to be replaced… and if + or- .001 (or better) is required a digital caliper may be the better choice than the dial IMHO.

OT: Micrometers should be set to a jo block because the thread can wear with always checking or setting at closed (zero) so making them off at measuring a part and still zero at zero. Yes when the zero and part check miss needed spec they should be marked (painted red) or go in the dumpster.
 
I have no doubt Gordon’s measuring devices are good quality even though I have not used them.

His caliper pressure regulating device and the clutch device found on many micrometers give credence that operator skill is important. A heavy handed guy might crank down harder than a lady or light handed guy with depending on feel alone, and never feeling to a gauge master. Dial micrometers have a pressure control and are best used comparing to a jo block stack, so reducing the need for feel..

I made this video several years ago and it shows IMO that a constant pressure gives constant results.

Each of the 5 calipers demonstrated were zeroed (0.00mm)at 12 and although the results vary depending on the number it can be seen that the results are identical for each caliper at 12, 3, 6 and 9. The calipers IMO receive a hard handed treatment as they "drop" to each number.

The measurement pressure used is 4-5N.

Caliper measurement pressure // www.FMS-DK.com - YouTube
 
Bro...the kid is looking for beginner info...he gives not 1 fuck about your gadgets (although I will capitulate and say they are neat). Add something useful or move along.
 
Not the best choice but with having a master diameter and a digital caliper one can set zero on the master part, and then when checking made parts look for zero. This is good with using a less than perfect digital caliper. Yes you get plus and minus to the set (gauge)and to the desired size... not the actual part size.

Master diameter might be a gauge or a closely inspected part. Perhaps one checked with a micrometer or a plate check.

So getting a better check than setting caliper to zero at closed jaws or to a square gauge block because the gauge block set and the closed set are on the highest place along the jaws not the place the diameter might check..

Yes this might be a good time to replace the device. Still in a high production shop one may wear out calipers at a high rate and so making production checks at a good cost savings.. cant hardly beat calipers for ease and speed.
 
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