Dial Indicators

[kiwi_007]

Some may think I have a problem, I seem to collect dial indicators, micrometers and, well just about all quality measuring tools.

Below is a photo of some of my dial indicators, as you will notice most are metric, this is because I do most of my work using the metric system. Although when I started school, imperial was "the" standard, but I hadn't finished school and it was changed to metric, I still used imperial until I made the conscious decision to go "metric" and now even though I do most of my work in metric I do use Imperial when it's called for (ie I'm too lazy to convert all the measurements).

Anyway, my favourite brand of dial indicator is "Compac". Some 24+ years ago I won an auction on Ebay, the auction was for a 10ths Starrett Last word and another dial indicator that was metric 0.01m. When they arrived I did rather like the "other" dial indicator which happened to be a Compac 213, this has proved to be a very nice repetitive and reliable indicator and between it and the Comapc P51G they are the two I use the most.

Recently I picked up an imperial Compac to add to my collection and it has made me look at all my dial indicators and made me question why none of my metric indicators have the resolution of the latest Compac I bought.

To save everyone doing the conversions, but you are most welcome to check that I'm right if I'm not please let me know
0.0001" = 0.00254mm
0.0002 = 0.00508mm
0.0004 - 0.01016mm
0.0005 = 0.0127mm
0.001 = 0.0254mm
0.002 = 0.0508mm
0.004 = 0.1016mm
0.005 = 0.127mm

0.001mm = 0.0000394"
0.01mm = 0.000394"
0.07mm = 0.002755897"
0.1mm = 0.00394"
0.25mm = 0.00984249"
0.4mm = 0.01574798"
0.5mm = 0.01968498"

So if you look at the photo you will notice the dial indicator on the top left has markings every 0.001mm (1um or 0.0000394") and half a rotation is 0.07mm (0.0027"), but it has the shortest contact stem (8.6mm) and the dial is 33mm to give a bit of comparison the length of the contact stem on the Mitutoyo 513-404 is 18.7mm.

Most of the metric dial indicators I own have 1/2 rotation of the dial of either 0.25mm (0.0098") or 0.4mm (0.016"), the Mitutoyo 513-501 has 0.07mm (0.0027"), the Mahr 800SRM has 0.1mm (0.00394")
The Tesatest has the smallest dial 25.4mm, followed by the Compac 213 & 244LA 27mm, Mahr 800s & 800SL 30mm, Mitutoyo 513-501 & 513-504 are 33mm, Interapid 312-1 & Mitutoyo 512-404 38mm, and the largest at 40mm are the Compac 212GL, P51G, P3GA and Mahr 800SRM.

The dial indicator that made me study my dial indicators was the Compac P3GA, with a dial diameter of 40mm it's 1/2 rotation of the dial of 0.002" (0.0508mm) and divisions of 0.0001" (0.00254mm) it certainly looks the easiest to read.
None of my other dial indicators have the large face 40mm or the 1/2 rotation of 0.002" (0.0508mm), 0.0001" (0.00254mm) divisions with a contact stem length of 16mm.

With age my eyes aren't as good as they used to be and the more crowded the dial the harder to read, I'm not sure what others think but what is your favourite dial indicator and why?

 

[mksj]

Compac 215GA, although now sold under the Brown & Sharpe TESA name. Pretty much the only one I use anymore. Large 1.575" dial, 0.004" per revolution with a measuring range of 0.024" with high linearity and repeatability. My collection is not quite as many but I have a half dozen in mostly different configurations.


Getting older I am going blind, and only have one good eye...

 

[RJSakowski]

Compac 215GA, although now sold under the Brown & Sharpe TESA name. Pretty much the only one I use anymore. Large 1.575" dial, 0.0004" per revolution with a measuring range of 0.024" with high linearity and repeatability. My collection is not quite as many but I have a half dozen in mostly different configurations.
View attachment 395308

I believe you mean .0004"/div?

 

[graham-xrf]

You never have to "go metric", nor "go inches" if you have an established relatable "feel" for what is good, bad, good enough, etc. You can adopt a unit for the current task, and stay with it, and never feel the need to know what the equivalent is in the other units, unless you happen to need to get a particular dimension from a drawing, or to get something to fit. Doing the conversion is quick and easy, and once it suits the measure instrument you have handy, you are back to "comfortable".

Starting with the mass of conversions. Sensibly, you did realize that a list of inches in relatable integer increments yields a bunch of awkward numbers in millimetres, but you can, of course, make another table with the situation reversed, and see the awkward numbers in inches.

Like you, I had inches in part of my childhood. Darn, but I also had pounds, shillings, pence, florins and half-crowns, ha'pennies, ticky's bobs, quids, guineas, farthings and sixpences. Also pounds-weight, slugs, poundals, carets, and hundredweights! There can be very strong attachments to what one is used to. Here in UK, the metric system was adopted 1818, yet in 1960's there was more formal legislation to get it more widely used, to reduce costs. We are metric throughout industry, but we have miles, and mph speeds and pints of beer. The money system absolutely had to be reformed in 1971, but was also used to mask a de-facto devaluation because of mad inflation!

I can move from one set of units to another, and be comfortable in either. As it happens, the US system (inches) was based on metric exact 2.54cm as a practical standard by Carl Johansson, and Henry Ford, somewhat ahead of the formal international bringing together of the US inch, being very slightly too large (I think), and the British inch being slightly too small (was it that way around?) I think it's great that these two guys got together, and used Jo-Blocks to make all engineering fit and work, and in effect, enforce a standard where governments could not.

What units you use, and some will swear by, is quite strongly related to what you grew up with before age 10. There is, of course, a whole bunch of comedy, and an apparent partly politically motivated aspect (at least there is in the UK). In South Africa, back in 1970s, they moved to metric with a will, using a simple brutal strategy. You could use inches all you liked, but they required that all new stuff sold be metric. School rulers, your dial gauge, your lathe, whatever. They put up the new km road speed signs with covers, and switched the covers overnight at a weekend, and muddled through a few hours of chaos!

Here at HM, the demographic means we will see a leaning to inches and thous and tenths. Thus hang in there with America, Liberia, and Myanmar.
It does mean that we may find it convenient to have a metric micrometer as well as an inches version to hand

 

[mmcmdl]

I haven't seen my favorite in quite some time . Way back when getting started , I bought a Mititoyo that I had to pay for it weekly out of my apprentice paycheck . This was my my first thus my favorite for no other reason . Over the years after accumulating 50 or so , they all do the same thing . For talking $$$$ indicators , I like my old Mahr Millimesses and Alina sets just because I know they're accurate .

 

[RJSakowski]

You never have to "go metric", nor "go inches" if you have an established relatable "feel" for what is good, bad, good enough, etc. You can adopt a unit for the current task, and stay with it, and never feel the need to know what the equivalent is in the other units, unless you happen to need to get a particular dimension from a drawing, or to get something to fit. Doing the conversion is quick and easy, and once it suits the measure instrument you have handy, you are back to "comfortable".

Starting with the mass of conversions. Sensibly, you did realize that a list of inches in relatable integer increments yields a bunch of awkward numbers in millimetres, but you can, of course, make another table with the situation reversed, and see the awkward numbers in inches.

Like you, I had inches in part of my childhood. Darn, but I also had pounds, shillings, pence, florins and half-crowns, ha'pennies, ticky's bobs, quids, guineas, farthings and sixpences. Also pounds-weight, slugs, poundals, carets, and hundredweights! There can be very strong attachments to what one is used to. Here in UK, the metric system was adopted 1818, yet in 1960's there was more formal legislation to get it more widely used, to reduce costs. We are metric throughout industry, but we have miles, and mph speeds and pints of beer. The money system absolutely had to be reformed in 1971, but was also used to mask a de-facto devaluation because of mad inflation!

I can move from one set of units to another, and be comfortable in either. As it happens, the US system (inches) was based on metric exact 2.54cm as a practical standard by Carl Johansson, and Henry Ford, somewhat ahead of the formal international bringing together of the US inch, being very slightly too large (I think), and the British inch being slightly too small (was it that way around?) I think it's great that these two guys got together, and used Jo-Blocks to make all engineering fit and work, and in effect, enforce a standard where governments could not.

What units you use, and some will swear by, is quite strongly related to what you grew up with before age 10. There is, of course, a whole bunch of comedy, and an apparent partly politically motivated aspect (at least there is in the UK). In South Africa, back in 1970s, they moved to metric with a will, using a simple brutal strategy. You could use inches all you liked, but they required that all new stuff sold be metric. School rulers, your dial gauge, your lathe, whatever. They put up the new km road speed signs with covers, and switched the covers overnight at a weekend, and muddled through a few hours of chaos!

Here at HM, the demographic means we will see a leaning to inches and thous and tenths. Thus hang in there with America, Liberia, and Myanmar.
It does mean that we may find it convenient to have a metric micrometer as well as an inches version to hand

You forgot to mention pints and stones. As I recall, they are the two biggies.

 

[graham-xrf]

@RJSakowski
Heh heh! Yes indeed. At some stage around 1326, Edward II decreed an inch was three fat barleycorns. So check out what your shoe sizes are today. That we always have units hangovers is a human thing, and not particularly "American" or "Portuguese" or whatever. Folk are OK with getting to use all sorts of units they can see advantages for, but they will resent like hell any attempt to force anything on them. For a whole lot of stuff, there is no particular need to change, and there would only be some costs involved if you do.

We have much less problem if the machine we covet and love, and do need for the business, was made in Germany, or Taiwan, or if the lovely gal we are smitten by would respond to carets (or fractions thereof) much like Jackie Evancho as Kitty, (or pre-dating me a bit), say Marilyn Monroe + Jane Russell !

Let me try for some more..
Fathoms. rods, perches, poles, bushels pecks, slugs. US gallons defined via the Queen Anne wine barrel. What's a ton? Oh yes - 2200lb. Huh? No, that's a "long ton"! Go for 2000 pounds. Umm, it does not take long for somebody to tell you pounds is a mass, and what it weighs kind of depends where you are. 1000kg = 1 metric ton. Oh yeah, that's about 2200 pounds weight, is it not? Did someone say there were 5280 yards in a mile? What's a furlong? Oh yeah, one side of an acre. The short side is a surveyor's chain = 1 cricket pitch worth!

Just lately, I have been getting used to eV (electron volts), barns (as in, could hit the side of a barn), and Angstrom Units.
I am somewhat in envy of the @kiwi_007 collection of dial indicators. Wow! Wish I had some of that kit!

[Edit - a "barn" is about the cross section area of a uranium nucleus ]

 

[kiwi_007]

Compac 215GA, although now sold under the Brown & Sharpe TESA name. Pretty much the only one I use anymore. Large 1.575" dial, 0.004" per revolution with a measuring range of 0.024" with high linearity and repeatability. My collection is not quite as many but I have a half dozen in mostly different configurations.
View attachment 395308

Getting older I am going blind, and only have one good eye...

Mark, Thanks for that information about the 215GA, and I can certainly relate to that last sentence, although I've only had one eye for the last 40+ years

 

[Winegrower]

Compac 215GA, although now sold under the Brown & Sharpe TESA name. Pretty much the only one I use anymore. Large 1.575" dial, 0.004" per revolution with a measuring range of 0.024" with high linearity and repeatability. My collection is not quite as many but I have a half dozen in mostly different configurations.

I believe you mean .0004"/div?

RJ, this indicator shows 0.004 per revolution, 0.0001 per division, just as mksj says.

 

[Arielht500]

@RJSakowski
Heh heh! Yes indeed. At some stage around 1326, Edward II decreed an inch was three fat barleycorns. So check out what your shoe sizes are today. That we always have units hangovers is a human thing, and not particularly "American" or "Portuguese" or whatever. Folk are OK with getting to use all sorts of units they can see advantages for, but they will resent like hell any attempt to force anything on them. For a whole lot of stuff, there is no particular need to change, and there would only be some costs involved if you do.

We have much less problem if the machine we covet and love, and do need for the business, was made in Germany, or Taiwan, or if the lovely gal we are smitten by would respond to carets (or fractions thereof) much like Jackie Evancho as Kitty, (or pre-dating me a bit), say Marilyn Monroe + Jane Russell !

Let me try for some more..
Fathoms. rods, perches, poles, bushels pecks, slugs. US gallons defined via the Queen Anne wine barrel. What's a ton? Oh yes - 2200lb. Huh? No, that's a "long ton"! Go for 2000 pounds. Umm, it does not take long for somebody to tell you pounds is a mass, and what it weighs kind of depends where you are. 1000kg = 1 metric ton. Oh yeah, that's about 2200 pounds weight, is it not? Did someone say there were 5280 yards in a mile? What's a furlong? Oh yeah, one side of an acre. The short side is a surveyor's chain = 1 cricket pitch worth!

Just lately, I have been getting used to eV (electron volts), barns (as in, could hit the side of a barn), and Angstrom Units.
I am somewhat in envy of the @kiwi_007 collection of dial indicators. Wow! Wish I had some of that kit!

[Edit - a "barn" is about the cross section area of a uranium nucleus ]

Not forgetting the tad and the gnats for non critical measurement