Digital Calipers

[VicParticipant @vic]

“​Where possible I use the parts I'm working as gauges. One part starts from measurements, and the others are shaved to fit or reference it”

I suspect many of us on here work like that Dave, I know I do.

[JasonBModerator @jasonb]

Posted by Andrew Johnston on 03/08/2018 11:58:56:

Posted by roy entwistle on 03/08/2018 09:05:13:

Andrew How about proper calipers and a two foot rule

Yes and yes;

If nothing else I find micrometers better for depth and large bore measurements. The small calipers are mostly used when I am modelling OTS parts for incorporation into 3D CAD assemblies.

Andrew

That's not a proper caliper, you want one of these

Yes I do prefer my depth mic to the digital one, comes down to feel in use also helped that I got a nice Lufkin one 0-3" in exchange for a bit of 5mm steel plate from Jo, fiver well spent.

Also sounds like I will have to give up making these glow, diesel and flame licker engines with their close fitting pistons as I only have a Far Eastern machine, should not have sold the Emco to make way for it

[Former MemberParticipant @formermember32069]

[This posting has been removed]

[roy entwistleParticipant @royentwistle24699]

Jason Yes that is what I mean by a caliper. Roy

[Neil WyattModerator @neilwyatt]

Posted by Michael Gilligan on 03/08/2018 07:50:16:

For those who might only vaguely recall the advert in Neil's subtitle: **LINK**

http://www.hatads.org.uk/catalogue/record/4f75737d-980d-4e67-9e29-7b417de5fd7a

MichaelG.

1977!

Oh dear, showing my age…

Neil

Edited By Neil Wyatt on 03/08/2018 16:27:54

[SillyOldDufferModerator @sillyoldduffer]

Posted by Barrie Lever 1 on 03/08/2018 16:06:32:

…

Jason

…

You keep on making your engines, I expect they run nicely and meet your needs etc.

…

That's done my inferiority complex no good at all! I reckon Jason works twenty times faster than me, and it's better made, and he finishes things…

Oh dear

Dave

[Anonymous]

Posted by JasonB on 03/08/2018 15:32:35:

That's not a proper caliper, you want one of these

Any questions?

Andrew

[Neil WyattModerator @neilwyatt]

Posted by Andrew Johnston on 03/08/2018 18:37:44:

Posted by JasonB on 03/08/2018 15:32:35:

That's not a proper caliper, you want one of these

Any questions?

Andrew

Just one… have you had them calibrated?

N.

[JasonBModerator @jasonb]

Posted by Andrew Johnston on 03/08/2018 18:37:44:

………………………………………..

Any questions?

Andrew

How did our predecessors manage with those, a pair of oddlegs, pair of dividers and not a lot more?

I can't remember the last time I used mine on metal, probably when I was making a Stuart 10V in my teens, I do still use them for wood turning though. The oddlegs and dividers do still see use on metal.

J

[Mick B1Participant @mickb1]

Posted by JasonB on 03/08/2018 19:31:27:

Posted by Andrew Johnston on 03/08/2018 18:37:44:

………………………………………..

Any questions?

Andrew

How did our predecessors manage with those, a pair of oddlegs, pair of dividers and not a lot more?

They worked to bigger tolerances! I remember reading about George Stephenson or a contemporary being delighted when cylinders were consistent within the thickness of a fingernail.

I had a friend whose father was a watchmaker in 1950s Northampton. It was claimed he could work to a couple of thou with calipers, rule and jeweller's loupe. I can believe that, but it will have cost so much time and fiddle-faddle that I'll bet it'd only be done in a few places.

[Gas_mantle.Participant @gas_mantle]

You are making me feel old here – I still use old spring calipers and a steel rule regularly to get close to the size I want. With an Item in my lathe or mill I always have spring calipers set using a rule to very slightly over the finished size then just happily cut away till the caliper fits before taking proper measured cuts.

Admittedly I make fairly simple models compared to some on here but I find its a way that suits me

[richardandtracyParticipant @richardandtracy]

Our predecessors managed by long apprenticeships and a lifetime of learning.

We have to make up for our time and experience poverty by more expensive machines. To get good results on a basic machine your skill has to make up for the lack from the machine. Not something that all of us can supply.

Regards

Richard.

[Anonymous]

Posted by Neil Wyatt on 03/08/2018 19:24:30:

Just one… have you had them calibrated?

No. There's no manufacturer identification on them. So I suspect they were probably made by my father as part of his apprenticeship. So they will have been assessed.

Andrew

[Anonymous]

Posted by JasonB on 03/08/2018 19:31:27:

How did our predecessors manage with those, a pair of oddlegs, pair of dividers and not a lot more?

As has been said they tended to work to much looser tolerances. If accuracy was required then much work with files and emery cloth ensued, which is time consuming. Not to say I haven't resorted to same but it's not something I want to do on a regular basis.

Andrew

[Neil WyattModerator @neilwyatt]

Posted by Andrew Johnston on 03/08/2018 20:58:42:

Posted by Neil Wyatt on 03/08/2018 19:24:30:

Just one… have you had them calibrated?

No. There's no manufacturer identification on them. So I suspect they were probably made by my father as part of his apprenticeship. So they will have been assessed.

Andrew

That was an attempt a humour… how would you calibrate a plain caliper?

[Ian WelfordParticipant @ianwelford58739]

well you could tighten the nut….🧐

[Mike E.Participant @mikee-85511]

Posted by Neil Wyatt on 03/08/2018 21:50:13:

Posted by Andrew Johnston on 03/08/2018 20:58:42:

Posted by Neil Wyatt on 03/08/2018 19:24:30:

Just one… have you had them calibrated?

No. There's no manufacturer identification on them. So I suspect they were probably made by my father as part of his apprenticeship. So they will have been assessed.

Andrew

That was an attempt a humour… how would you calibrate a plain caliper?

Lock it within a couple of thousandths, then carefully stone the ends to fit the sample you wish to duplicate.

[Anonymous]

Posted by Neil Wyatt on 03/08/2018 21:50:13:

That was an attempt a humour…

Oh dear, my advice would be don't give up the day job just yet.

Andrew

[SillyOldDufferModerator @sillyoldduffer]

My digital calipers are a mixed bag. For a long time I used a £4.99 Lidl caliper that still works despite being dropped, stood on, cracked, used as a scribe, and hacked for an Arduino project. This was an extraordinarily good buy – the battery lasts about 2 years.

Upstairs I keep a £9.99 DIY store caliper or rough work. Main fault, it tends to lose zero, so every measurement has to be taken twice to confirm it's not moved. Very annoying.

In the workshop I'm currently using a 'better inexpensive' caliper bought from Ketan for £20. I actually bought it for its ability to display imperial fractions, which is handy once in a blue moon, but it works as well as the Lidl, and it feels smoother in operation. I also own a Dasqua that cost about £30, which has the useful 'Absolute Zero' feature, and it is even smoother. I don't use it much in case I break it, and because, usually, if the Ketan caliper isn't good enough, I go straight to a micrometer. The problem with the Dasqua is I don't use it often enough to justify the purchase.

In terms of their ability to measure millimeters there's not much difference. However, the more expensive calipers do 'feel' better, and measure more consistently, which inspires confidence and saves time. Looking at them, it's not obvious why the more expensive calipers feel smoother because the external construction is similar, I suppose the gibs are better inside.

What I really need is a left-handed digital caliper. The display on a right-handed caliper is obscured by the chuck when checking diameters on a lathe. This is a major problem!

Dave

[Clive IndiaParticipant @cliveindia]

Posted by Clive India on 03/08/2018 12:44:13:

I bought a caliper with fractions as well as mm and in., thinking it would be helpful – not sure why now.

For me it is just about the most useless thing in the world. Measuring something nearly always comes out at 128ths. The next thing is to wonder just what that is. Increase until you get to 64ths and then 32nds and so on.
Clever, but mainly useless.
Anyone else found one of these useful? Am I missing something?

Surely someone else must have one?

[Mick B1Participant @mickb1]

Posted by Clive India on 04/08/2018 09:39:33:

Posted by Clive India on 03/08/2018 12:44:13:

I bought a caliper with fractions as well as mm and in., thinking it would be helpful – not sure why now.

For me it is just about the most useless thing in the world. Measuring something nearly always comes out at 128ths. The next thing is to wonder just what that is. Increase until you get to 64ths and then 32nds and so on.
Clever, but mainly useless.
Anyone else found one of these useful? Am I missing something?

Surely someone else must have one?

When I first saw one in shop I had no idea who might buy or use such a thing. 128ths? Didn't think anyone had ever heard of those as a real thing. Anybody I ever worked with went to thous anywhere lower than a 64th – primarily because drawing general tolerances where I worked specified +/- 1/64 for any fractional dimension.

Also because the caliper I saw was made like a tin opener, of stamped and folded sheet.

Edited By Mick B1 on 04/08/2018 09:55:36

[roy entwistleParticipant @royentwistle24699]

I think the left handed one could be very useful.

Roy

[Peter G. ShawParticipant @peterg-shaw75338]

FWIW, I use the following:

150mm, 0.01mm resolution, 0.01mm accuracy Starrett dial caliper.

100mm, 0.02mm resolution, unquoted accuracy, "Whiteface" dial caliper.

150mm, 0.05mm resolution, unquoted accuracy, slide vernier caliper.

I also have a Rolson digital caliper, 150mm 0.01mm resolution, can't remember the quoted accuracy, and an Aldi digital caliper, 150mm, 0.01mm resolution, can't remember the accuracy.

Of these, the Starrett is head and shoulders above the rest for "niceness" to use. The "Whiteface" is ok around the lathe because of its size, but its movement is atrociously rough. The slide vernier is ok, but a bit short on resolution! Of the digitals, both "eat" batteries hence are not used. In addition, the Aldi measurement system is rubbish.

In terms of accuracy, I have 25mm, 50mm & 75mm Mitutoyo micrometer standards. Using these, the slide vernier appears dead accurate; the Starrett similarly, and the "Whiteface" ok but note the poorer resolution. I haven't bothered with the digitals because for one thing any reading is subject to plus or minus one digit. Which means that, eg, 10.00mm could be measured as 9.99 or 10.01mm. Hardly accurate in my view! By the way, I did all my testing at room temperature of 25 degrees C having allowed the instruments and standards to soak overnight. Also, I kept manual handling to an absolute minimum.

As you guess, I'm not a fan of digital measuring devices!

Peter G. Shaw

[Neil WyattModerator @neilwyatt]

Posted by Peter G. Shaw on 04/08/2018 13:51:24:

Which means that, eg, 10.00mm could be measured as 9.99 or 10.01mm. Hardly accurate in my view!

A misunderstanding of how they work. Having done some software for digital scales, they 'read' internally to much greater resolution.

The 'precision' of the reading is such that 10.00 covers >9.995 to <10.005, no different from a vernier caliper.

Accuracy is another issue, but my test with standards showed the typical digital vernier to be as accurate as a typical vernier one*.

Neil

*My 'not cheap' vernier required me to enlarge the slots for the scale so I could set the zero correctly…

[Neil WyattModerator @neilwyatt]

Brand	Model Number	Packaging		Price	Resolution Metric	Resolution Imperial	Reading on 25.00mm test bar at ~21 C
Mitutoyo		Black plastic box	0.00		0.01	0.0005	25.00
Moore & Wright		Black plastic box	0.00		0.01	0.0005	25.00
Machine DRO		Black plastic box	0.00		0.01	0.0005	25.00
Proops		Black plastic box	0.02	?	0.01	0.0005	24.99
Workzone (Aldi)		Clear fronted box	0.01	?	0.01	0.0005	25.03
Unknown glass filled Nylon		None	0.11	?	0.1	0.01

 

Edited By Neil Wyatt on 04/08/2018 16:26:46

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