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Author Topic: Digital Vernier Chat  (Read 4667 times)

Colin Bishop

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Digital Vernier Chat
« on: March 30, 2015, 08:21:40 PM »

I have a digital vernier and also a manual one and prefer the latter!

Colin
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john44

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Re: Re: Digital Vernier
« Reply #1 on: March 30, 2015, 10:44:18 PM »

I have a digital vernier and also a manual one and prefer the latter!

Colin
Each to their own Colin, my eyesight being what it is the digital is best for me  {-)


John
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derekwarner

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Re: Re: Digital Vernier
« Reply #2 on: March 31, 2015, 01:23:22 AM »

It' got to be a sad state of education >>:-(, when Technical and Further Education only teach students to read a vernier caliper's metric graduations......but now also allow vernier calipers with a digital TV screen in the top corner to be used during practical measurement tests

A vernier caliper is just that.......it is a gauge...... accurate dimensions should be made with micrometers and recorded as such

Take a piece of 1 5/8" precision chromed bar = 1.625 +0.000/-0.0005".........give it to a young trades person and you may get the diameter recorded as 41.2 or 41.3 diameter....which are clearly both incorrect

You think this is unimportant?.........well how do these young people manufacture components for a class of fit?.....whether this be to a BS Standard, a DIN Standard, an ISO Standard or even an Australian AS/NZ Standard..........

Not blaming the youngsters .......just the dingbats that make the rules.......and invariably in OZ...would be Degree qualified professional Engineers who themselves may not be capable of reading a micrometer or analogue caliper.........Derek
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Derek Warner

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derekwarner

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Re: Re: Digital Vernier
« Reply #3 on: March 31, 2015, 04:02:15 AM »

Sorry......must be approaching dingbat status myself ...............

Just the dingbats that make the rules  >>:-(
Just the dingbats who make the rules   :-)).......

sooooooooooooo at least I am humble and modest enough to accept my error....... ;D Derek
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Derek Warner

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inertia

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Re: Re: Digital Vernier
« Reply #4 on: March 31, 2015, 08:37:34 AM »

Derek
Few people would of have recognised that as a mistake. Here in the UK the mention of Imperial units in a classroom is now apparently regarded as treasonable.
I'm quite happy with my digital vernier but I don't work to model engineering tolerances. I just wish I'd waited a few years before buying it; mine has a 'Moore and Wright, Sheffield' inscription and cost over seventy quid.
DM
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Danny

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Re: Re: Digital Vernier
« Reply #5 on: March 31, 2015, 09:09:00 AM »

Dave, you'll still be able to use your M & W to measure harp string gauge (or more probably pitchfork tine diameter) when we have thrown our "oriental" stuff in the bin!
I have a defunct digital vernier which seems to think that 76897 is slightly greater than 912567, which I presume is its native measuring system based on the fit of components originating from that area.
I also have an M & W 0-25mm mic which I like using but invariably attempt to use the graduations as thousandths of an inch from old habits which results in everything becoming roughly 1:25 scale whether I like it or not.
I am now on the lookout for a 150mm mechanical dial vernier with the additional requirement that it can also be used as a centre punch/hammer and an adjustable spanner, plus having the retractable rod for poking set silicone out of nozzles (you see, I am up to date on modern tool usage!).
Cheers
Danny

jarvo

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Re: Re: Digital Vernier
« Reply #6 on: March 31, 2015, 11:33:12 AM »

My old metalwork teacher called them calibrated G clamps


Mark
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cos918

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Re: Re: Digital Vernier
« Reply #7 on: March 31, 2015, 12:22:43 PM »

Can not see what the fuss is about. Aldi sell a digtal vernier for less than £10 . this tool will do 2 decimal places which is accurate for most model making .
 Yes you can digtal vernier or micrometers that go down to 3 or more decimal places but they cost a lot more and is over kill for modeling .
All messuring tool digtal or manual would need claberating if they were to be used in industry were tiny dimensions are required.
I did engerning course over 20 years ago and we only did metric .
Eletronics are comming cheeper and better so tools 20 years ago that were very very expensive can not be had for not alot of money.
so I say a BIG THANKYOU to Alid for supplying me a good quality tool at a very good price .

john
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grendel

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Re: Re: Digital Vernier
« Reply #8 on: March 31, 2015, 08:44:44 PM »

I have 2 verniers, one stable plastic digital one (not cheap) and an even less cheap Mitutoyo steel one, inherited from an engineer great uncle in law- accurate to 2 decimal places, the vernier stretching to 50mm.
Grendel
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derekwarner

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Re: Re: Digital Vernier
« Reply #9 on: March 31, 2015, 09:34:38 PM »

Guys...I was not taking a shot at inexpensive vernier callipers and yes I also use a pair  :embarrassed: on occasion and  :-)) the stated accuracy is totally acceptable for most tasks.......but just the technical educational system that permits the use of such devices in practical measurement tests......Derek
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Derek Warner

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NFMike

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Re: Re: Digital Vernier
« Reply #10 on: March 31, 2015, 10:29:56 PM »

The problem with digital devices and the education systems is that a lot of people think that accuracy = number of decimal places displayed.
So if the display on my laser 'tape-measure' says 3.123 metres then it must be 3,123 mm.
But the device is only +/- 3mm accuracy, so it's actually somewhere between 3,120 and 3,126 mm. That's a big error if you are cutting something to fit  :embarrassed:

Mad Scientist

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Re: Re: Digital Vernier
« Reply #11 on: April 01, 2015, 01:21:20 AM »

...I am now on the lookout for a 150mm mechanical dial vernier with the additional requirement that it can also be used as a centre punch/hammer and an adjustable spanner, plus having the retractable rod for poking set silicone out of nozzles (you see, I am up to date on modern tool usage!).
Cheers
Danny

Don't forget WiFi capability, built-in GPS and laser level/light sabre! - Tom
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tigertiger

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Re: Re: Digital Vernier
« Reply #12 on: April 01, 2015, 02:34:45 AM »

Some thoughts/things spring to mind.


I have seen woodworkers fettle/adjust their tools and talk in the order of thou (Americans on youtube or TV).
They they build with wood. If it rains outside the table get bigger, and wood will marginally twist, cup, and bow, but by more than a few thou.


I have digital calipers, but usually only read them to the nearest 0.5mm. I just use it for quick sizing of hardware and components.


Imperial measurements are only used in the US as far as I am aware. What is the point of teaching European school kids about a system of measurements that they will never use. Except perhaps in a social history lesson.


Why teach high school students to read vernier scales, if it is unlikely that they will ever use them. Those who do go on to university to study engineering can learn it there, if the course designers perceive that the needs of graduate engineers includes it. It is better to fill the high school curriculum with things that are more relevant to today's world.
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derekwarner

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Re: Re: Digital Vernier
« Reply #13 on: April 01, 2015, 03:23:00 AM »

Well TT...in OZ we are metric.......but Woodside Petroleum in Western Australia use General Electric LM2500 gas turbines to power generators which drive gas refrigeration liquification compressors...those turbines have GE [made under licence] Woodward governors   ........these are 100% imperial in dimension......[& then we sell the LNG to Japan for a pittance >>:-(]

[GE do not market or sell spares for their made under license governor's.......jus send it back to them & the repair the components at a very expensive cost structure]

So some bright spark in WA....measured all of the hydraulic control system components for the governors ...yes in mm and fractions of mm.........you guessed it, greater than 90% of the replacement seal elements dis not fit the seal housing cavities

My task on the 9th of March this year was to reverse engineer all of the original hydraulic seal elements back to square one.......all in inches and parts there of :-))

So there is a valid reason or need to be able to read & comprehend imperial micrometers and vernier calliper's......

Interestingly...the same GE LM2500 turbines are one of the most popular turbine engines in the world...aviation, marine, power generation just to name a few ...yes and all in inches" ;) ...... Derek

 http://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&cad=rja&uact=8&ved=0CEAQFjAF&url=http%3A%2F%2Ffas.org%2Fman%2Fdod-101%2Fsys%2Fship%2Feng%2Flm2500.htm&ei=VlUbVcCUAsX38QXHioKIBQ&usg=AFQjCNFfY40GXCtnfBQy7ctubF7HKYsRLw&bvm=bv.89744112,d.dGc
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Derek Warner

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tigertiger

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Re: Re: Digital Vernier
« Reply #14 on: April 01, 2015, 05:29:49 AM »

Yes Derek, and that is the exception that proves the rule.

Personally, I strongly believe that we should base our high school education systems on the norms and not the exceptions. Those who need to know about the exceptions, can learn them on the job. Most of the skills I needed for the job, were not covered in school, and that is pretty standard across the globe.

I did learn the imperial system in school. I also learned about woodwork and metal work (separately), engineering drawing (using pencil, paper, pens), I also learned how to use a slide rule (pretty much redundant today, with some exceptions in the mechanical trades). I didn't learn about plastics, fibreglass, carbon fibre, or for that matter most alloys, 3D printing, designing with CAD, or computer science, etc. Where I have needed a new skill I learned elsewhere, as we all have.

Many of the jobs skills of yesteryear have almost disappeared from some western countries (farrier, sheet metal worker, ship builders, miner). My generation were taught skills for the manufacturing industry, which has pretty much disappeared in UK. Most mechanics today are fitters, who were not trained how to rewind a starter motor. Today the knowledge based, and service industries prevail. Kids need to be prepared for this brave new world. Even if they can't change a light bulb, the little blighters are brilliant at sorting out my IT gremlins.

One of the keys to modern education is for students to be able evaluate sources of information, and to be able to apply and synthesize it. Why the change? We might ask. With the internet, knowledge is only click away. If we think of information choice, rather than information overload, we can see why. Many of the skills I learned in school are much less relevant in today's world. Most car mechanics are now just fitters, they don't need to know how to re-wind a starter motor for example.

Yes there will always be exceptions, we still need engineers 'who can' (much fewer than before), and people can and still do train for those specialisations. But the chances of a high school leaver in the UK going into engineering today, are slim to none.
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david48

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Re: Re: Digital Vernier
« Reply #15 on: April 01, 2015, 08:59:37 AM »

Annoyed Aberdeenshire
I was trained as a fitter by the very nature of the word we had to make things to fit ,we were not spare part changers ,cutting key ways with hammer and various chisels and files on occasions on older machines just to name one job ,so we had to be able to use all measuring devices be it metric or imperial .
That job title seems to have passed in the heavy plant game because of advances in technology I now see jobs advertised as   Technicians .
David
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tigertiger

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Re: Re: Digital Vernier
« Reply #16 on: April 01, 2015, 09:20:49 AM »

Yes I know what you mean with job title inflation. Mr Kwik Fit fitter is not the same.
I once worked in a call centre, where I was a Telephone Sales Executive, where I answered the phone. I couldn't even take a leak without permission. I remember when the title Executive used to mean something too.
You can also do short courses and be called a carpenter/joiner/plumber.
And as for the Modern Apprentice...

Like it or not the world has moved on. I think the only trades left with an rigour are those involving safety, i.e. gas and electricity.
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grendel

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Re: Re: Digital Vernier
« Reply #17 on: April 01, 2015, 01:36:13 PM »

you have to be very careful nowadays - reliance on electronic devices can lead you astray, take the example of one site, a buildings foundations were laid out to an accuracy of 1mm by GPS (over a 100m building) when they came to install the actual building the bolt holes at the far end were 6mm off, in the modern culture of blame throwing just about everyone called the blame to just about everyone else. the reality was that the GPS was reading 100m - AT SEA LEVEL, the site being above sea level meant that the 100m measurement was in reality 100,006 mm. they had forgotten to apply a site altitude correction factor of 0.99994 due to the greater circumference at this height.
This shows that even using supremely accurate equipment you can still be fooled by an electronic readout .
you can only get this degree of accuracy from GPS when you have a site station as part of the GPS setup, a fixed GPS transmitter (or two on a large site) that gives a local reference for the GPS survey equipment. It was initially thought that the GPS had just not been accurate enough, but in the end its downfall was that it was too accurate, and that the steelwork was made to too tight a tolerance.
Grendel
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vnkiwi

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Re: Re: Digital Vernier
« Reply #18 on: April 01, 2015, 02:31:58 PM »

That just goes to show, its the human interface which always stuffs up.
People forget that, and do that oh so dangerous thing that if the readout say's its that, then it is.
Same with computer design and drawing, reliance on what the computer tells one, is a given.
Not so, it may give you a what you think it is giving you, or it may be giving you rubbish, all dependant on the user input.
I'm a dinosaur, so in my day, one had to have a clear picture within ones head, to be able to actually put down on paper the information for someone else to build it. Whatever it is.
Today, most young un's have no idea what it is until they see it on the computer, so tell me how then do they know if its right, if it can actually be built, etc. I've seen increasing reliance over the past decade, more and more reliance on electronics, and the assumption that if the computer tells me it is, then it is, and right it is to. Then when oldies like myself look over their shoulder at what they have, they can't fathom that its wrong, or that there is a cheaper, simpler way of doing the same thing.
In my day, you worked it out with a pencil, (very versatile things pencils), nowadays, we have computers to do all that.
Well poop in poop out, as its just another fancy pencil, and if the idiot driving it has no idea, then so be it.
Grendel's example happens all to often, to greater and lesser extents. %) :o O0
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Colin Bishop

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Re: Digital Vernier Chat
« Reply #19 on: April 01, 2015, 05:32:19 PM »

I normally use my manual analogue vernier for measurements down to an accuracy of 0.5mm which is fine for me as I am a modelmaker and not a model engineer where greater accuracy is required. Comes in handy for checking my car tyre tread depth too. One thing I like about it is that you can look at the measurement on the scale and estimate by eye any fractions between the graduations. I have a micrometer too but never need it.

With regard to Metric v Imperial it will be a very long time before the latter is truly phased out, maybe a couple of centuries. For example, on my Japanese car the nuts and bolts are a mixture of Metric and Imperial depending on what they are being used for and there is a huge amount of infrastructure, buildings, bridges, machinery etc. etc. which is constructed on Imperial measurements and still have a lifetime of many, many years during which maintenance will be required.

Engineering professionals will need to grapple with both systems for a very long time yet! many of us on here are equally at home with both systems so we are really clever clogs!

Colin
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tica

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Re: Digital Vernier Chat
« Reply #20 on: April 01, 2015, 07:14:00 PM »

I'm out of a craftsman´s family but took to the dark side as an electronics engineer  ok2 but has also been trained in using welding equipment, manual lathe and millingstation.

Today I'm working as an Supplier Quality Engineer with responsibilities within electronic parts, PCB's, plastic granulates and injection moulded parts and it include choosing and validating the best way of measuring specific features. At my workplace it has shown that when using "non-skilled" workers they are more confident in reading a digital vernier or micrometer than manual versions.

In my opinion the best solution is to choose and understand the tool that you will use for a specific task.

2 examples:

One of my "non craftsman skilled" engineering friends did a quality control of rubber O-rings with a vernier and did a complaint to the supplier about the diameter of the rubber, damm I would have loved to be in the receiving end of that one  %%

We got a part that was produce in the US and designed in co-operation with a EU country, it had several critical dimensions and we had to bye in expensive equipment to do the IQC. We never managed to get it right and we found out that the US firm designed the part in inc. and then redid the drawing in metric. Doh  >:-o

So I uses both digital and manual vernier and micrometers depending on what I have at hand or what the task requires.

BTW: I have also had the joy of owing a Toyota with mixed metric and imperial bolts  <*<
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Brian60

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Re: Digital Vernier Chat
« Reply #21 on: April 01, 2015, 07:24:39 PM »

The mention of the difference in a building length reminded me of our local hospital. About 10 years ago they built a new maternity unit, 4 floors, that connected to the main hospital (14 floors) that was built circa 1964.

Of course the modern architects designed the new block with metric measurements. When it came to connect the two together with a 100 metre covered walkway/corridor, the thing had a sharp downward deflection in its centre. The third floor of the new building dropped down to the second floor of the old building because of the innacuracy of lining up metric with imperial {-)

Subculture

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Re: Digital Vernier Chat
« Reply #22 on: April 25, 2015, 10:42:22 PM »

When I went to technical college, we had to make items using both imperial and metric systems, although the machines and measuring tools were metric, which kept things interesting.

At some point you have to start phasing out a system, if a newer type is to become a standard. I much prefer working with metric, just a much more logical and simple system, and it was designed to be that way.

I use calipers for most of my machining, not as accurate as a micrometer, but accurate enough for the bulk of work I do. I far prefer digital to analogue versions, think they've been a real boon to be honest.

cabman

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Re: Digital Vernier Chat
« Reply #23 on: April 26, 2015, 01:06:14 AM »

All this talk about vernier callipers, micrometers accurate to .0005mm reminds me of my mate who was a joiner at Hull City Council. He always said working to accuracy like that was no good in his job because they had to be cock on!
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McGherkin

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Re: Digital Vernier Chat
« Reply #24 on: April 26, 2015, 02:17:35 AM »

The mention of the difference in a building length reminded me of our local hospital. About 10 years ago they built a new maternity unit, 4 floors, that connected to the main hospital (14 floors) that was built circa 1964.

Of course the modern architects designed the new block with metric measurements. When it came to connect the two together with a 100 metre covered walkway/corridor, the thing had a sharp downward deflection in its centre. The third floor of the new building dropped down to the second floor of the old building because of the innacuracy of lining up metric with imperial {-)

There is a certain RN ship which was built in two halves, but when they were put together they didn't quite line up on one deck, so there is a nice big ramp in the middle of the corridor there between the two differing levels!


I can assure you all that the modern day fitter (well us lot anyway) are trained to use Metric and Imperial as required, and still know how to read manual verniers (I prefer them to the 'leccy ones anyway as I swear they're more accurate and they tend to mix a lot better with lathe coolant), but a well calibrated set of Micrometers still wins the day.
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