Calipers – Dial v digital

[ChrisHParticipant @chrish]

Having just had both my digital 150mm/6" admittedly cheap calipers fail in the last few weeks, why I don't know, both have decided to give random widely inaccurate readings, also switching units at random, so am now considering what to replace them with, dial or digital.

My thought re dial is that OK, it's analogue and more 'mechanical', but it doesn't have a battery to fail or electronics to throw a wobbley, therefore in the long term more dependably, if less quick or versatile in units to read.

Has anyone here got any views on this subject at all please?

In the mean time, I'm glad I have my old 250mm vernier caliper to fall back on; it maybe only basic handronic in operation, only in metric and may need peering at closely and slower to read, but it doesn't fail me when I need it.

Chris

[ChrisHParticipant @chrish]

[Michael GilliganParticipant @michaelgilligan61133]

Chris,

Good [typically Mitutoyo] digital calipers are much more reliable than the budget ones.

That said; I still have a liking for my old [also Mitutoyo] dial caliper; but even they are prone to occasional mysterious jumps of the reading !! … For safety, the little pinion is spring loaded and, if you happen to get [say] some Brass particles stuck in the rack, the pinion can jump a tooth.

Scrupulous cleanliness is essential.

MichaelG.

[John ReeseParticipant @johnreese12848]

I have a "good" Mitutoyo 8 inch digital caliper that sits on the shelf until I need it for critical word. It would cost over $200 to replace it. For routine non-critical work I use a $19 Chinese digital. They work fine for a while. When they die I replace them. I think I have 1 or 2 spares on the shelf.

I definitely prefer digital over dial calipers. A small speck of swarf on the rack can really mess up a dial caliper. Digitals are immune to dirt. A digital will let you measure c-c of holes without doing any math.

[Danny M2ZParticipant @dannym2z]

Always my first 'go-to' tool for day to day measuring to a thou, my Mitutoyo dial caliper is used regularly. Before using I drag a slip of paper between the jaws to clean them and check zero. As already noted, they can jump a tooth but seriously, this has happened about twice in 30 years and the instructions show how to use a piece of brass shim to make a simple reset tool.

For more precise work I use a Moore & Wright tenths reading vernier micrometer and to be honest, I have not found a requirement to use my expensive digital tools for so long that they are stored without batteries installed with the exception of a cheap digital caliper used as a drilling/boring depth indicator attached to the lathe tailstock.

I am not quite a Luddite as I do have an ancient calculator in the workshop that always seems to have 25.4 programmed as a constant in the memory.

* Danny M *

[Bill PudneyParticipant @billpudney37759]

I don't like stuff with batteries, or electronics generally. No doubt this makes me another Luddite. I get by with, in order of precision, a good quality steel rule, a Mitutoyo vernier (no dial), and a M & W Micrometer (0-25mm) a Starret 25 – 50mm, an M & W imperial depth mic, a "cheap" 5 – 30 inside Mic, and luxury, a 14 to 17mm bore Mic. The only digital measuring thing used is a "box of angles", I'm paranoid about the battery going flat………….. This lot does me!!

cheers

Bill

[Neil WyattModerator @neilwyatt]

The advantages of decent digital verniers are the smoothness of the action, battery life and temperature stability.

I use my Mitutoyos more than my M&Ws because the M&W auto power-off very quickly which is annoying.

Ones that go dodgy generally need the scale cleaned with meths and a new battery.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 26/10/2017 08:03:35:

… digital verniers …

.

[Mick B1Participant @mickb1]

I was a shopfloor machinist in the '70s when dial calipers first appeared. Loads of machinists bought them but they started to slip teeth very quickly. This was in the days when the Mitutoyo name had absolutely none of the quality significance it has today, but I took a chance and bought a Mitutoyo 6" vernier instead – which I still use from time to time, because I didn't feel the dial calipers were trustworthy.

I use an M&W value line digital for most work, with an old Mitutoyo vernier mic for accurate diameters. For rougher work I've also got an Aldi digital which still seems to work after multiple dredgings with coaldust, oil, swarf and suds (though you have to wipe it clean and rezero!). I guess I still won't trust dial calipers…

Edited By Mick B1 on 26/10/2017 08:41:07

[Neil WyattModerator @neilwyatt]

Posted by Michael Gilligan on 26/10/2017 08:32:33:

Posted by Neil Wyatt on 26/10/2017 08:03:35:

… digital verniers …

.

You know I came up with a sophisticated* argument why digital vernier is appropriate.

Neil

*In the original sense.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 26/10/2017 08:43:52:

*In the original sense.

.

[Martin KyteParticipant @martinkyte99762]

One obvious advantage of digital is the ability to set the zero wherever you require. For example distance between holes of equal diameter can be found by measuring the inside diameter of one hole and zeroing the caliper, Subsequent mesurement between the outer circumference of the two holes gives you a direct read of the centre distance. Similarly setting the caliper to zero at the reuired diamter when turning gives you a read out of how much needs to come off the part. Anything that removes the need to calculate will eventually save a mistake.

Plus the fact that you can switch from metric to imperial at will.

I do still posses a dial caliper but I don't remember when I last used it.

regards Martin

[IanTParticipant @iant]

I think it's all down to personal preference Chris.

I have a (good) Vernier caliper and a cheap digital one (but I don't have a 'dial' caliper). I invariably use the Vernier unless I'm doing something where it's particularly useful to be able to switch between metric/imperial or (more likely) measure a difference (using the zero facility). One reason is that I prefer using the fine setting adjustment on the Vernier (the cheap digital one just has a knurled knob) but I suspect the main reason is just a matter of personal habit – I've had the Vernier a long time and it's just very natural to use it.

Drifting off topic slightly – I also have an older Vernier gauge set up as a short height gauge (held upright in a block) and have added a digital scale to that but I still set-it with the Vernier mainly. The digital scale is useful for quick checks/comparisons though – as I don't have to pick it up all the time. For my small woodwork I have a very nice digital marking gauge which I do find very useful (easy to set) – and I've never owned a more traditional type…. so back to the point about what is familiar/comfortable I think..

Of course if I want accuracy – then I have a number of micrometers – both metric and imperial.

Regards,

IanT

[Chris Evans 6Participant @chrisevans6]

I have proper verniers and prefer the "feel" if needed for an accurate size check. However my go to daily use is cheap digital calipers from Aldi. One set on metric one on imperial and a new one in the drawer as back up. My first Aldi caliper is now over 8 years old. The three of them cost less than half my previous Mitutoyo caliper which I gave away as it was an old style with a small read out size.

[SillyOldDufferModerator @sillyoldduffer]

On the downside, a digital caliper has a battery that goes flat just when you need the stupid thing most!

On the upside: digital calipers have an unambiguous display that can switch between Imperial and Metric. They also have a resettable zero and perhaps fractions and an absolute function. Most useful to me is that digitals come in a cost range suited to purpose. By that I mean I can use a cheap caliper for rough work, for example as a scribe, without worrying about spoiling a good tool. When a cheap caliper dies, goes wonky, or gets broken I throw it away. There are no tears. I also keep a more expensive caliper in a safe place for more important work. Damaging one of these is much more painful!

Finally, when accuracy matters my preferred tool is a micrometer.

Dave

[Brian GParticipant @briang]

Bought several Kennedy digital calipers more than ten years ago for work, one was in my desk drawer along with the calibrated test bars (now well out of date) and a dial caliper when the factory closed so I "disposed" of them. Dead reliable, and despite having both absolute and increment measurement and a display that never times out the battery lasts many times as long as those in the Aldi caliper I keep in my desk. Meanwhile, I am not even sure where the dial caliper is, it is so long since I used it.

Brian

[Martin KyteParticipant @martinkyte99762]

What about stiff legged calipers and Jenny Odd Legs.

:0)

[ChrisHParticipant @chrish]

 

I have an imperial 0-1" mic, a 0-25mm, 25-50mm and a 50-75mm mics and an 5-30,, inside mic. I love using the mics, it's what I am familiar with. I have a digital height gauge which is also a delight to use and, until recently, had 2 cheapo digital calipers which were convenient for the reasons stated above – the readily availability to switch units and reset zero when required etc. I also have a 0-250mm vernier and a 0-400mm (I think, it's so long since I saw it) vernier which are at least reliable if slow!  The mics were – are – used as final measurers, the digital calipers only for rough measuring to near the finished dimension.

But the digital units were cheapo ones and I realised that to get a good one needed some (to me) serious dosh spending. Hence the consideration for a dial caliper. I had not heard of the meths trick – thanks for that Neil, I will try it and see if it helps. Am reluctant to buy another cheapo digital if it's only going to go down the same route eventually, they may be cheap individually but not accumulitively in the long run. Not got the budget for an expensive digital one, have other things to spend the money on first so, as above, hence the dial consideration.

I do appreciate those who have given their views, it have given me food for further thought, thank you.

The first digital went in the bin after becoming impossible to use in a meaningful way; the current one has started to go down the same route – not switching on, switching off by itself, reading about half what the reading should be, suddenly switching units half way through, zeroing on its own in the middle of measurement, and generally making a complete nuisance of itself instead of helping me. It was treated to a new battery not long ago, I will try another new one and the meths trick but if it continues to rile me it's going to follow the other one into the bin!

Chris

Edited By ChrisH on 26/10/2017 11:28:08

[Peter G. ShawParticipant @peterg-shaw75338]

I find that my two digital calipers "eat" batteries, so much so that I've stopped using them. I have a 0.05mm resolution true vernier caliper, a 0.01mm Starrett dial caliper and a "White Face" dial caliper with a resolution of 0.02mm. Of these, the Starrett is by far and away the smoothest and hence nicest to use. Unfortunately it's a bit big sometimes at 150mm measuring length so the "White Face" at 100mm measuring length gets as lot of use around the lathe. The vernier, whilst dead accurate according to a trio of 25, 50 & 75mm Mitutoyo test gauges, is reserved for jobs where the 0.05 resolution doesn't matter that much.

Another factor is the specification of the digitals – plus/minus 1 on the least significant digit. So is 10.00mm 10.00mm? Or 9.99mm? Or 10.01mm? Not convinced of the superiority of digital!

Go for a good quality dial.

Peter G. Shaw

[ChrisHParticipant @chrish]

Peter – had not considered a 0-100mm unit, only 0-150mm caliper. What you say about everyday use around the lathe is interesting, thanks for that, something else to ponder!

Chris

[duncan webster 1Participant @duncanwebster1]

If you're chasing thous use a micrometer. My old Sylvac digi caliper has just died, the display lights up, but it won't zero, switch units or increment when you move the slide. I call this dead, but it must be well over 15 years old. I've tried taking the battery out and leaving it for a bit. I note that the modern one from MDRO has much shorter battery life, and the battery goes flat even if it's not switched on. Yesterday I noticed that if you switch it on, zero it, switch it off, set it on a test bar, switch it back on it gives the correct reading, so off doesn't mean off, it only turns the display off. Just buy the batteries in bulk at exhibitions or off ebay.

And yes the 100mm one is very useful especially on the milling machine where it can get into places the big one can't

Edited By duncan webster on 26/10/2017 12:22:48

[Phil H1Participant @philh196021]

Does anybody know where to get a small (less than 6&quot traditional vernier i.e., without the battery or the dial?

I bought a not so cheap digital version a few years ago and it went into the bin quite quickly – completely unreliable. I have exactly the same issue as Duncan i.e., trying to access a component under a milling machine.

My 40 year old Rabone and Chesterman is still going strong but it is just a little bit too long.

Phil H

[Dave MartinParticipant @davemartin29320]

Posted by Martin Kyte on 26/10/2017 09:10:51:

One obvious advantage of digital is the ability to set the zero wherever you require. ….

Also useful if you can't see the display and need to move the jaws to get the caliper out – I've only had to do this a couple of times but very useful. Had to take a measurement in a blind spot so when calipers were 'on' the spot, press the zero button; you can then move the jaws as much as you like. When the caliper is out in a readable location, close the jaws together and the display will show the measurement, albeit with a leading minus sign. Just don't forget to re-zero properly before using again!

Dave

[Martin KyteParticipant @martinkyte99762]

Posted by Dave Martin on 26/10/2017 12:45:15:

Posted by Martin Kyte on 26/10/2017 09:10:51:

One obvious advantage of digital is the ability to set the zero wherever you require. ….

Also useful if you can't see the display and need to move the jaws to get the caliper out – I've only had to do this a couple of times but very useful. Had to take a measurement in a blind spot so when calipers were 'on' the spot, press the zero button; you can then move the jaws as much as you like. When the caliper is out in a readable location, close the jaws together and the display will show the measurement, albeit with a leading minus sign. Just don't forget to re-zero properly before using again!

Dave

I have to say I've never thought of that one. Quick, send it in as a Tip you may get a prize out of Niel.

regards Martin

[SillyOldDufferModerator @sillyoldduffer]

There's a bunch of factors that reduce accuracy and precision when you get into the detail. First you have to know what you have and compare like with like. For example:

• Dial types are typically ±0.02mm but many are ±0.05mm.
• Digitals are also typically ±0.02mm but some are ±0.01mm and a few ±0.005mm.

So any digital will outperform a ±0.05mm dial type, and the best digitals outperform the best dials. However, I bet most of us own calipers only good to ±0.02mm irrespective of whether it has a dial or a digital readout.

Awkward questions arise about any caliper's claim to accuracy as soon as you look at the detail. Do you ensure that the object and the caliper are both at the same temperature before taking measurements? Do you wear gloves when handling the caliper? Both digital and dial caliper are vulnerable to dirt, dial mechanisms particularly so: is the instrument clean? How repeatable are measurements? Is the instrument accurate over it's full scale or just in one place? Does it have an up-to-date Calibration certificate? If you don't have an up-to-date calibration certificate, a long list of problems may be hidden under the bonnet. Wear, bent jaws, loose gibs, skipping teeth, or other damage may be making the instrument untrustworthy.

Digital and analogue displays are both imperfect. A fault of the digital display on a ±0.02mm caliper is that it implies an accuracy of 0.01mm, which is a big fib. The faults of the dial display are that it's subject to mechanical and parallax errors plus a dial can be misread ± whole units at the revolution level, ie 10.05 read as 11.05mm

Worst of all is operator error. Not everyone is good at measuring! Getting the jaws aligned on the object isn't always easy. The pressure applied by the operator is both critical and difficult to judge. Too little and the reading will be low. Too much pressure and the caliper will bend.  Soft objects like plastics may deform.

One thing that makes me chuckle is chaps on YouTube 'proving' that their calipers are better than another make by checking a gauge block. The problem is operator bias. If you know the correct answer in advance, expect to get the answer you expected rather than the truth. As operator bias is usually subconscious rather than dishonest, nothing is proved by this type of testing. If you really want to know how good you and your instrument are, measure the dimensions of unknown objects handed to you randomly by a third party. Some who do this will be pleasantly surprised, most will be moderately disappointed, and a few horrified.

Like as not in the typical workshop both types are 'good enough' in the right hands. I say use whichever you prefer.

Dave

Edited By SillyOldDuffer on 26/10/2017 13:42:15

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