vernier calpier

[Hornet 6]

Digital caliper, vernier callipers and dial callipers all have one thing in common.
None of them are accurate to better than .001", no matter what resolution is claimed.

Did the digital thing many years ago as a machinist, these day just use dial or vernier, usually vernier for reliability.
You just know a vernier will work, it will be zeroed, will never drift and you cant push a button by accident and screw it all up.

Neil.

 

[ChesterP]

Why would any re-loader need better than 0.001" accuracy? (answer: you don't!). With my fading eyesight, a good digital one all the way . You're right of course about the reliability of manual ones and I have a selection of manual calipers and micrometers here but for reloading I use my digital ones (with the exception of case length checks where I use dial calipers).

 

[Alantoo]

snip...
You just know a vernier will work, it will be zeroed, will never drift and you cant push a button by accident and screw it all up.

Neil.

I never use any micrometer or caliper without checking zero. It is the quickest way to ensure the jaws/Anvil etc. are clean.

True the vernier, dial caliper and mechanical micrometer won't drift but if there is a bit of crud on the jaws you will still get a false reading.

Alan

 

[Hornet 6]

I never use any micrometer or caliper without checking zero. It is the quickest way to ensure the jaws/Anvil etc. are clean.

True the vernier, dial caliper and mechanical micrometer won't drift but if there is a bit of crud on the jaws you will still get a false reading.

Alan

The quickest way to scrap a job is to trust a digital vernier to be zeroes just because you checked before the last one you measured.
You need to check the zero every single time yo pick it up, as that is when you will inadvertently touch a button.
As for crud on the jaws, you are supposed to wipe them clean every time you measure something.
As for the +/- .001" in a machine shop they are never trusted as only form of measurement unless the item concerned has +/1 .010" tolerance.

Neil.

 

[simonl]

If you decide on digital ones...check that they have auto power off. I kept coming to the box and finding the battery flat because I wasn't in the habit of having to switch off the micrometer or vernier calipers.

Alan

Most of the cheap ones draw significant current whether on or off - so the auto power-off isn't what you'd expect it to be.

 

[Alantoo]

For simple case measurement I use a generic £20 digital caliper. Easy to read and use, especially if you have not used a vernier scale before.


I first realised my eyesight was deteriorating when I could no longer focus on a vernier caliper close enough to read it.

I tried a dial caliper but still prefer spectacles and a vernier...or the digital one.


If you decide on digital ones...check that they have auto power off. I kept coming to the box and finding the battery flat because I wasn't in the habit of having to switch off the micrometer or vernier calipers.


Mitutoyo are great instruments, one of my verniers were made by them, but I don't think their quality is necessary for the case measurement function.


I always clean the caliper contact surfaces and check zero (with the digital ones re-zero) every time I pick them up.


Alan

Digital caliper, vernier callipers and dial callipers all have one thing in common.
None of them are accurate to better than .001", no matter what resolution is claimed.

Did the digital thing many years ago as a machinist, these day just use dial or vernier, usually vernier for reliability.
You just know a vernier will work, it will be zeroed, will never drift and you cant push a button by accident and screw it all up.

Neil.

I never use any micrometer or caliper without checking zero. It is the quickest way to ensure the jaws/Anvil etc. are clean.

True the vernier, dial caliper and mechanical micrometer won't drift but if there is a bit of crud on the jaws you will still get a false reading.


Alan

The quickest way to scrap a job is to trust a digital vernier to be zeroes just because you checked before the last one you measured.
You need to check the zero every single time yo pick it up, as that is when you will inadvertently touch a button.
As for crud on the jaws, you are supposed to wipe them clean every time you measure something.
As for the +/- .001" in a machine shop they are never trusted as only form of measurement unless the item concerned has +/1 .010" tolerance.


Neil.

Sorry if I have misread it, but by quoting my post and then starting your sentences "You need..." and "As for..." your post comes over as though you were arguing against the points I made…and yet we seem to be in agreement with you just repeating what I have said with slightly different words?


In case for some reason you have taken umbrage, I am not trying to teach anyone to suck eggs. My comments regarding the cleaning and crud were for the OP's benefit. I thought your “You just know a vernier will work, it will be zeroed” comment, if taken at face value was open to possible misinterpretation by a first timer. In case, given his original question, he has not had the benefit of either training or learning from experience to know that you are "supposed to wipe them clean".


Alan

 

[Alantoo]

Most of the cheap ones draw significant current whether on or off - so the auto power-off isn't what you'd expect it to be.

Ah, maybe the auto-power off is not such an advantage as I thought it would be then.

As long as I remember to switch mine off the battery is good for a year or two.

Alan

 

[Hornet 6]

In case for some reason you have taken umbrage,

Alan

Not me Alan, I didn't actually intend it to be argumentative.
I spent my working life mostly in a machine shop, I cannot even begin to guess at the amount of scrap that is turned out all because people trust a digital calliper, or because they didn't check or clean it before use.

It amazes me how many new reloaders who have no background in engineering are buying digitals as if they are the complete answer to all measuring, as it isnt like you you may just scrap a case, potentially you could just as easily have a case rupture if loaded too long and jam the bullet in the lands with a max load.
On a lighter note, I find the thought of people trimming cases and getting frustrated that they cannot get each case the exact same size according to the holy grail of measuring amusing.

Neil.

 

[Alantoo]

Not me Alan, I didn't actually intend it to be argumentative.
I spent my working life mostly in a machine shop, I cannot even begin to guess at the amount of scrap that is turned out all because people trust a digital calliper, or because they didn't check or clean it before use.

It amazes me how many new reloaders who have no background in engineering are buying digitals as if they are the complete answer to all measuring, as it isnt like you you may just scrap a case, potentially you could just as easily have a case rupture if loaded too long and jam the bullet in the lands with a max load.
On a lighter note, I find the thought of people trimming cases and getting frustrated that they cannot get each case the exact same size according to the holy grail of measuring amusing.

Neil.

I have an old Ward 7 Prelector turret lathe and an even older Woodhouse & Mitchell gap bed / change wheels. The Ward I always think of as the ultimate pre CNC British machine. Elegant like a greyhound, beautifully engineered...but just happening to weigh 4.5 tonnes!

In these days of CNC machines how are those calibrated?...do they suffer from drift as well?

Alan

 

[Highlandsjohn]

Originally Posted by Hornet 6
Not me Alan, I didn't actually intend it to be argumentative.
I spent my working life mostly in a machine shop, I cannot even begin to guess at the amount of scrap that is turned out all because people trust a digital calliper, or because they didn't check or clean it before use.

It amazes me how many new reloaders who have no background in engineering are buying digitals as if they are the complete answer to all measuring, as it isnt like you you may just scrap a case, potentially you could just as easily have a case rupture if loaded too long and jam the bullet in the lands with a max load.
On a lighter note, I find the thought of people trimming cases and getting frustrated that they cannot get each case the exact same size according to the holy grail of measuring amusing.

Neil.

I agree with Neil 100%.Especially the last sentence.

CNC machines being controlled by Computer, less opportunity for human error and bumps. john

I have an old Ward 7 Prelector turret lathe and an even older Woodhouse & Mitchell gap bed / change wheels. The Ward I always think of as the ultimate pre CNC British machine. Elegant like a greyhound, beautifully engineered...but just happening to weigh 4.5 tonnes!

In these days of CNC machines how are those calibrated?...do they suffer from drift as well?

Alan

Originally Posted by Hornet 6
Not me Alan, I didn't actually intend it to be argumentative.
I spent my working life mostly in a machine shop, I cannot even begin to guess at the amount of scrap that is turned out all because people trust a digital calliper, or because they didn't check or clean it before use.

It amazes me how many new reloaders who have no background in engineering are buying digitals as if they are the complete answer to all measuring, as it isnt like you you may just scrap a case, potentially you could just as easily have a case rupture if loaded too long and jam the bullet in the lands with a max load.
On a lighter note, I find the thought of people trimming cases and getting frustrated that they cannot get each case the exact same size according to the holy grail of measuring amusing.

Neil.

 

[Alantoo]

I agree with Neil 100%.Especially the last sentence.

CNC machines being controlled by Computer, less opportunity for human error and bumps. john

It was the similarity of digital control that made me ask. Digital calipers include a basic computer as well. I was wondering if the computer in a CNC machining station calibrated itself from the tooling at each process...or whether they also used mechanical/physical end stops like my old Ward 7.

Alan

 

[Highlandsjohn]

It was the similarity of digital control that made me ask. Digital calipers include a basic computer as well. I was wondering if the computer in a CNC machining station calibrated itself from the tooling at each process...or whether they also used mechanical/physical end stops like my old Ward 7.

Alan

quote..or whether they also used mechanical/physical end stops like my old Ward 7.quote

Ah yes Alan,I remember those stops well. I am 'old school' centre lathe,I expect there will be electronic sensor 'stops' on CNC.

There will be some on here who will chime in.john

 

[Southern]

CNC press brakes already have electronic stops. You can set it to bend 90 degrees, and insert different thicknesses of the same metal into the brake; lasers will read the angle and automatically adjust the depth each time, accounting for the spring back.

 

[Doric]

I use a Chinese made VERYNEAR CALIPER one which uses both metric and imperial measurements and have had it for years and is acurate.the only problem with the cheapo Chinese ones is that if using the ruled measurement's the imperial increments are in tenth of an inch so not true imperial but works fine with the digital display and is acurate to 0.0005".

 

[Hornet 6]

<snip>and is acurate to 0.0005".

No it isn't, it may have resolution of .0005" but it is not accurate (or re-peatable) to that, as said elsewhere, it is possible accurate to .005" at best on a very good day.
That is what callipers in general are for, a quick check, in engineering no production engineer would trust a calliper alone unless working with .010" +/- tolerance.

Neil.

 

[Doric]

Lidel have them for sale at £10 at the moment, I bought one yesterday ( just in case my spare one goes missing you understand) checked it several times and always returns to zero.

 

[Doric]

As I said Neil VERY NEAR CALIPER good enough for the job in hand but they are not a micrometer.