Dial Indicators

[MWParticipant @mw27036]

Now, many many years ago, i probably would've been beaten over the head with a large rock until my innards spilled out and then later burned for tea time, for asking such a diabolically mad question;

I use a cheap Clarke dial indicator and wondered why the branded ones are so much more to buy, so do you really get alot more accuracy for your cash?

Michael W

[MWParticipant @mw27036]

Whats the worth in it?

[NJHParticipant @njh]

The more expensive versions probably have jewelled movements. It probably is not so much a case of improved accuracy as longevity. Greater sensivity too may be a factor but, for the average shed, the more exotic versions may be an indulgence!

Norman

( That said it's always nice to have good kit to use )

Edited By NJH on 11/02/2016 14:56:41

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Michael Walters on 11/02/2016 14:38:06:

Now, many many years ago, i probably would've been beaten over the head with a large rock until my innards spilled out and then later burned for tea time, for asking such a diabolically mad question;

I use a cheap Clarke dial indicator and wondered why the branded ones are so much more to buy, so do you really get alot more accuracy for your cash?

Michael W

.

Think 'precision' [i.e repeatability] rather than 'accuracy' … and think repairability.

A virtual visit to Long Island Indicator will explain a lot.

MichaelG.

Edited By Michael Gilligan on 11/02/2016 14:58:35

[IanTParticipant @iant]

As usual Michael, bang on – exactly so.

IanT

[Nick_GParticipant @nick_g]

.

I saw on youtube a while ago some American guy doing such a side by side test of Mitutoyo and Chinese imported dial indicators.

The basic result was there was little difference in real world testing so long as the Chinese item was reasonably new. This guy was a full time pro so his kit would see regular use on most days. As such the Chinese one would quickly wear out. – As hobbyists with much less use we have to balance how long it would be before we took the cheap option to this point.

I have both quality ones and a cheap Axminster one. The quality Mitutoyo ones are smoother and have less 'bounce' to them and are generally much nicer to use.

The Mitutoyo ones were gifted to me so I was fortunate as they are not a cheap item and I certainly would have had a hard think before splashing out on such initially. But having used them I would replace with the same should anything ( e.g. me being a donk and dropping them ) unfortunate happen to them.

IMHO by buying a used quality one from the net may be a risk for such a delicate item as it may have had a good hiding. – "You pays your money and takes your chance."

Nick

[MWParticipant @mw27036]

Actually i think my one is a chinese no name, not a clarke per se, one is a little "sticky" on the plunger and the casing for it broke, i paid a little more for the lever type one, which is clarke, that seems to have a nicer feel to it, i still keep it in its box.

I guess in terms of "accuracy" it actually tells you on the dial how accurate the movements are, mine are to 0.01 of a MM but you could get accurate to 0.001 of a MM (if what is said is to be believed) it obviously gets much harder to make sense of the reading the finer you go, for general workshop use that is.

So i've discovered a new meaning to the word precision, that being repeatability and general sturdiness/product support if it does go wrong. I think my plunger one has almost "had it" to be clear.

you definitely learn from experience whats worth paying for and whats not,

 

Michael W

Edited By Michael Walters on 11/02/2016 16:06:21

[Chris Evans 6Participant @chrisevans6]

I have Mititoyo and Mercer lever type dial gauges. Both served me well when I made my living on the tools. I did buy a Chinese lever type for £21 some years ago which was about a quarter of the Mercer cost, it did not last long in a daily use environment.

[densleighParticipant @densleigh]

I have a Clarke Plunger one and it sticks all the time – so not much use.

To replace I bought a Mititoyo one and the difference is really amazing – it works every time!

Only echoes the mantra buy decent and be wise.

[Neil WyattModerator @neilwyatt]

The way to get precision and accuracy in your mind's eye is to think of target shooting.

A tight bunch of hits away from the bull is precise, but not accurate.

A loose bunch of hits clustered around the bull are accurate but not precise.

A tight group on the bull is b0th precise and accurate.

You can work with any or the three – precision without accuracy means you need to identify the error and allow for it. Accuracy without precision can be partly offset by averaging several measurements.

Obviously if you have both, you are in clover.

Neil

[HollowpointParticipant @hollowpoint]

I have both a draper expert and a mitutoyo. They both give identical readings but like others have said the mitutoyo is much smoother. When held next to each other its obvious the mitutoyo is build to a better standard, the materials feel better quality and the fit and finish is just better.

[MikeParticipant @mike89748]

I've had two Mitotoyos and a Borletti for around 30 years now, and all three are as smooth as when they were bought. A cheap Chinese job was binned after a couple of years – it just kept sticking and no amount of cleaning and lubricating with a tiny drop of watch oil seemed to improve things. I'd go with the general consensus – quality counts. A friend has an apt saying: "Always buy the one you're going to finish up with anyway."

[David ColwillParticipant @davidcolwill19261]

I have a Mitutogo (correct spelling) I paid £9.50 including shipping

David.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 11/02/2016 17:10:42:

The way to get precision and accuracy in your mind's eye is … ^^^

.

That's an excellent memoire, Neil

I would just add that; for an Indcator, the precision takes priority; whereas a Gauge demands both.

MichaelG.

[Chuck PickeringParticipant @chuckpickering45941]

Posted by Neil Wyatt on 11/02/2016 17:10:42:

The way to get precision and accuracy in your mind's eye is to think of target shooting.

A tight bunch of hits away from the bull is precise, but not accurate.

A loose bunch of hits clustered around the bull are accurate but not precise.

A tight group on the bull is b0th precise and accurate.

You can work with any or the three – precision without accuracy means you need to identify the error and allow for it. Accuracy without precision can be partly offset by averaging several measurements.

Obviously if you have both, you are in clover.

Neil

Great analogy, Neal. Had to copy and save that definition. Also shared it, with credit to you, on a couple Facebook groups I follow.

Chuck

[alan-lloydParticipant @alan-lloyd]

I always now use Verdict or Moore and Wright, having used the Chinese rubbish

[HollowpointParticipant @hollowpoint]

Posted by Mike on 11/02/2016 17:48:36:

A friend has an apt saying: "Always buy the one you're going to finish up with anyway."

I have a similar saying: "Buy sh*te buy twice"

[Anna 1Participant @anna1]

Hi,all.

At the risk of opening a can of worms, May I respectfully suggest that Neils analogy to

archery is not quite correct., ( and it is many years since studying metrology)

According to Collins dictionary the words Accurate and precise are interchangable.

If you hit the gold you are both accurate and precise and presumably within the tolerance you have set

If you have a cluster outside the gold you are both consistantly inaccurate and consistantly imprecise

and need to make an adjustment

If you are all over the place outside the gold with your sizing you have got a problem. And perhaps have a problem

with the machine or tool

Kind regards

Anna

[AjohnwParticipant @ajohnw51620]

I often use a mercer. 1/2" travel 0.0001" dti. I'm not keen on finger dti's. It's well used. From the design it might be 40 odd years old. I'm not sure when they stopped using glass or flat plastic and switched to a domed plastic one leaving the look of the dial the same. I also have a John Bull to the same spec. That one's pristine and on a surface plate type stand.

I also bought a Baty to the same spec not long after I found this forum. Nuts maybe and I doubt if the mercer will ever give up the ghost but this spec is hard to find these days. Some one on the for sale here has/had a number of old stock dti's for sale. I was extremely pleased by the price – over joyed in fact. Ideally the plunger end needs changing as the rad on it is too small really but these aren't expensive.

Some where I have another Mercer that I did use same apart from longer travel. It was dug out of a scrap bin and had been used for checking components. They were swung into place, a so called flip gauge. That one had a slight wobble if stuff in the lathe was turned the other way. Just a bit of needle wobble.

Initially I bought a not so cheap one and despite not all that much use really it packed up.

To be honest I don't think mitutoyo gauges will last as long as these type do.

John

–

[SillyOldDufferModerator @sillyoldduffer]

Posted by Anna 1 on 11/02/2016 20:28:37:

Hi,all.

At the risk of opening a can of worms, May I respectfully suggest that Neils analogy to

archery is not quite correct., ( and it is many years since studying metrology)

According to Collins dictionary the words Accurate and precise are interchangable.

If you hit the gold you are both accurate and precise and presumably within the tolerance you have set

If you have a cluster outside the gold you are both consistantly inaccurate and consistantly imprecise

and need to make an adjustment

If you are all over the place outside the gold with your sizing you have got a problem. And perhaps have a problem

with the machine or tool

Kind regards

Anna

 

 

Oh no, just when I thought I'd understood it!

Although Collins dictionary could be dismissed as non-technical it's harder to ignore JCGM 200:2008 which is the International Vocabulary of Metrology. I think this supports Anna rather than Neil.

It defines:

Measurement accuracy

closeness of agreement between a measured
quantity value and a true quantity value of a
measurand

NOTE 1 The concept ‘measurement accuracy’ is not a
quantity and is not given a numerical quantity value. A
measurement is said to be more accurate when it offers a
smaller measurement error.
NOTE 2 The term “measurement accuracy” should not
be used for measurement trueness and the term
measurement precision should not be used for ‘meas-
urement accuracy’, which, however, is related to both
these concepts.
NOTE 3 ‘Measurement accuracy’ is sometimes under-
stood as closeness of agreement between measured
quantity values that are being attributed to the measurand.

and

Measurement precision

closeness of agreement between indications or
measured quantity values obtained by replicate
measurements on the same or similar objects
under specified conditions 2.15

NOTE 1 Measurement precision is usually expressed
numerically by measures of imprecision, such as standard
deviation, variance, or coefficient of variation under the
specified conditions of measurement.

This history and practice of metrology is a fascinating Anna : I'm amazed Neil hasn't asked you for an article (yet)!

Regards,

Dave

 

Edited By SillyOldDuffer on 11/02/2016 21:45:30

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Michael Gilligan on 11/02/2016 14:56:39:

.

Think 'precision' [i.e repeatability] rather than 'accuracy' …

 

.

Anna, and Dave,

I believe my implicit definition ^^^ is consistent with the technical one cited by Dave.

MichaelG.

.

P.S. … Here is NPL's guidance document.

Edited By Michael Gilligan on 11/02/2016 22:09:11

[Anna 1Participant @anna1]

Hi, Michael,

I agree with your "precision" normally equating to repeatability.

Kind regards

Anna.

[VicParticipant @vic]

It's already been linked so if you saunter over to long island indicator you're see that even Mitutoyo aren't rated very highly compared to the Swiss made dial indicators. Apart from an old Starrett I got for one particular job all mine are top makes like Tessatast or Compac. Long Island now rate a German brand as well but I can't recall the name.

[AjohnwParticipant @ajohnw51620]

Mitutoyo came to the west as a cheap brand that no one trusted but much cheaper than the good western brands. On mic's they made a lot of noise about using carbide anvils. The fact is that they needed to because the spindles were plated and probably not hardened. It's much the same with many markets they entered – optics, microscopes and many other things. There early cars were interesting in some respects as well – a lot for the money and some rather clever ways of reducing the costs.

What people get these days off Mitutoyo is accurate items but in terms of life I don't think they will match up with what was made in the past and it's debatable if they need to really.

Couple of links that explain why they were so successful

https://en.wikipedia.org/wiki/W._Edwards_Deming

But this bloke deserves way way more credit than he usually gets. He also introduced a sort of philosophy associated with making things

https://en.wikipedia.org/wiki/Genichi_Taguchi

John

–

Edited By Ajohnw on 11/02/2016 23:42:39

[Peter KroghParticipant @peterkrogh76576]

Deming tried to sell US industry on his philosophy but they wouldn't bite. So he took it to Japan where they were basically starting over. The rest is history. By the time the method was popularized in the US, commonly known as 'Just-In-Time' (which is only part of the system) it was the '90s.

Pete@been there done that wore out the tee shirt

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