Digital Calipers

[Crow Choker]

Greetings-I'm new to the forum as a member, but have been reading it for a little over a year and have enjoyed it very much. Have been shooting black since the early 70's and been reloading since the mid-70's. Have a question and hope to glean any info from any of you that can respond. I've been using a dail caliper for approx 20 yrs, but want to go with a digital, I see the major reloading companies(RCBS, Lyman, Hornady) market stainless ones in the $30-40 range. I don't need one of the super priced $100 plus ones. The question of the day is, are the major reloading company ones all of the 'same feather' or does one have an edge over the other. I like to investigate all possibilities before buying a product-hate to buy something and discover later should have gone the other route. In the words of Captain Call "Can't tolerate it"! Maybe one of ya would know of another brand that is as good or better. Any info would be much appreciated. I'm posting here as I see CAS doesn't have a seperate reloading  section. Thank you in advance for any information.

[Pettifogger]

In that price range they are all made in China and probably all made in the same factory.  I've had some very expensive digitals and some cheap ones.  Bottom line, I stick with the dial caliper since it has no batteries to wear out.  The batteries always seem to fail when you need the caliper the most and sometimes the batteries cost more than the caliper to replace them.  I had a $250.00 Brown and Sharpe and they quit making the batteries that went in that.  No batteries, the caliper is junk.  It's now is a landfill someplace.

[Sir Charles deMouton-Black]

Get them at a discount tool store.  Like pettifogger said, all from the same sweatshop!

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[Dick Dastardly]

My dial calipers have never had a dead battery.   That said, there is something to be said about digital and the fact that it's easier to read and harder to misread.  If I were to buy one, I'd specify that it come with an extra battery.

DD-DLoS

[Delmonico]

Some of us old pharts could get by on a vernier type, also not hard to read, but it does take a little thinking. 

Got a pair of plastic dial calipers about 25 years ago, made in Switzerland, cost me $12.95, for reloading they are as good as needs to be and measures the same as the Starret one my brother has.

[Driftwood Johnson]

Howdy

Funny you should ask. I was just surfing for digital calipers over at Midway USA. They have a bunch of them in all different price ranges, with names like RCBS, Hornady, and S&W on them. When I zoomed in for a closer look, each and every one of them looked exactly like the Mitutoyo digital calipers I used to have at my last job. I'm talking about the first six or so on the page. I loved that caliper. It looks to me like these are all knockoffs from the same factory. At least the design of the electronics housing is exactly the same. I loved that caliper and may grab one of these.

http://www.midwayusa.com/Search/#digital%20calipers____-_1-2-4_8-16-32

Personally, I have been using a nice old Starrett dial calipers for years, but I may want to grab one of those digital babies. Personally, I would stay away from plastic calipers and stay with stainless steel.

[Rebel Dave]

Howdy

Most Dial Calipers today use one of the more common "watch type" batterys, so a dead batt should be no problem. as far as where to get one, try Harbor Freight, they are as resonable as any where. I still have my nice Mityoutoyo, and a cheaper one, and can see no diference in the calibration, or operation. I still use my ole thimball style mics, both metric, and inch, quite a bit. I have them all the way up to 6in.

Rebel Dave

[john boy]

I have 2 digitals and 3 manual calipers Chinese that I bought from Harbor Freight.  I measured their accuracy with certified plug gauges.  The digitals  are < 0.001, so I just add the number to what ever I am measuring.  Manuals are on the money

[Mako]

Crow Choker,
First of all the short answer; for reloading or general use an inexpensive metal caliper is totally satisfactory and I would trust the measurement to .001”.  This is of course if the operator knows how to correctly hold and use a caliper. I would avoid plastic calipers unless you are willing to limit the recorded measurement to at least ±.005”, in fact Mitutoyo will only specify their plastic calipers as having a resolution of ±.001 and an accuracy of ±.008”.

So those of you who hate long answers or an explanation of how things work you may now go on to the next topic…

For those who want to know; first of all digital calipers are alluring and look incredibly accurate considering they may read out to four or even in some ludicrous cases five significant digits.  Don’t let all of those displayed numbers fool you, they are unusable numbers past the 3rd place.  They are also nice because they allow you to easily switch between English and Metric measurements.

Digital calipers typically do not have the beam structure of a dial or vernier caliper and therefore do not have the repeatability or accuracy from purely a mechanical standpoint.  Some companies such as Starrett have sought to reduce this by introducing Carbon fiber stiffening members into their caliper beams.  But, they still only claim a resolution of .0005” and read out to three significant digits (.001”).    According to Starrett, “The best digital and dial slide calipers, regardless of resolution, are accurate to within .001” or 0.03mm, every 6” or 150mm. The best vernier calipers are accurate to .0005” or 0.013mm per foot or 300mm.”

Ordinary 6-in/150-mm digital calipers are made of stainless steel, and most have a rated accuracy of ±.001" (.02mm) and resolution of .0005" (.01mm).  These are not my specifications but Mitutoyo’s for their extremely popular ABSOLUTE Series 500 6 Inch  Digimatic Caliper.  These are not cheapies, they list for $141.  Please note Mitutoyo’s rated accuracy of ±.001 and this is for a quality caliper. Personally I think the best calipers either allow you to set the displayed digits to three significant digits, or have a display that limits it to three digits.  You will notice most displays show four significant digits but the resolution of the fourth place increments from 0 to 5 to 0. The reason I like three is it keeps us from thinking we are capable of accurately measuring anything smaller than .001” with a caliper.

Digital calipers are basically linear encoders.  A pattern of lines is etched directly on a printed circuit board in the slider. Under the scale of the caliper another printed circuit board also contains an etched pattern of lines. This forms a variable capacitor when a charge is applied. As the slider moves two capacitances are out of phase and circuitry in the head counts the lines The combination of these printed circuit boards forms two variable capacitors. As the slider moves the capacitance changes in a linear fashion and in a repeating pattern. The circuitry built into the slider counts the lines as the slider moves and does a linear interpolation based on the magnitudes of the capacitors to find the precise position of the slider. As you might imagine the spacing of the lines as well as the accuracy of that spacing plays heavily into the electronic accuracy of the encoder.

In our SOP for inspection we limit measurements with high quality digital calipers to .001” and consider the accuracy to be within ±.001 for purposes of measurement analysis.  In other words If a measurement of .0535” was taken it would be recorded as .054” and it’s reliability would be considered .0535±.0010.  So the dimension would be considered to fall somewhere between .0525” to.0545”.  With dial or Vernier Calipers we used to accept measurements in .001” increments and regard them as a recordable measurement.

So what would I do?  I would buy an inexpensive 4 or 6 inch steel digital caliper and limit my recorded measurements to whatever the third place rounds to.  The good news is that inexpensive digitals are plentiful and a great tool for the home user when limited to reading in thousandths of an inch. Notice I have don’t even quibble about the ±.001 accuracy, most of us aren’t capable of holding the caliper consistently or applying uniform pressure with the jaws to even take advantage of the accuracy.  So I’m saying I’ll accept any reading from my pards in thousandths of an inch if they used a caliper, if you are using a micrometer…Well that’s a completely different story and sure to make some readers here cranky because they think I have already gone on too long.

Regards,
Mako

[Delmonico]

Interesting, since I get the same with the Starret dial calipers and the same brand mike, two folks say my plastic calipers are no good.  As I said, mine are years old and made in Switzerland.  However to be truthful I'd give up either pair for a good 1" mike and a vernier caliper if that was my only choice.

I only use the calipers for OAL and case length, which don't need to be to 4 or 5 decimal places and use the 1" mike for anything else.   Seems the most logical.  As for digital, naw, not gonna trade something that works with out batteries for something that does, don't make much sense to me. 

[fourfingersofdeath]

My first set of vernier calipres was a set set made from sheet metal, sans dials and digital tomfoolery. I didn't have any confidence with it (especially after it fell off the bench and water came in during a storm. It was covered in rust and I used a wire brush to clean it up It wears a coating of oil now ). Then I picked up a light green plastic set, once again just plain old vernoers. This didn't inspire any confidence either them one day whem I was cashed up, I saw a Lyman dial caliper and paid a King's ransom for it in a plastic case. It is good to use. The digital ones were out then, but were mega expensive. It also confirmed that the two crappy ones I had been using were absolutely spot on! They sure are cheap now. The local guy who specialises in bankrupt tool sales, new tools and irrigation equipment (Yep! a real boy's shop) is selling a set of 4xMicrometers with digital readouts for $AU99!

My mate went to buy a set and he took along an old friend who is a tool maker/fitter and turner by trade and he bought along his mega expensive 30 year old German micrometers and measuring blanks or whatever you call them, because they didn't believe that the Chinee cheapies would be accurate. They were so accurate, they both left with a set. It is amazing how cheap stuff is now. The flip side of this is workers don't have real security and everyone is getting their wages and conditions screwed down. Ain't no easy answers!

[Crow Choker]

Thank you each and all for your info and response's. The real reason I have to admitt for going with a digital was ease of reading. My stainless dail one was given to me by a friend who operated a machine shop, while on routine patrol one evening. They were missing the plastic dial cover at the time, but I assume were not cheap new and have given good serivce. I'd like to compare them with a known objects demensions to check accuracy. Yep Pettifogger, have bought things in the past and when batteries need replacing, they cost more than the original item, wary on those deals. Yes Sir, Delmonico, sometimes the simpler roads and ways are just as good, sometimes better. Went to school when in classes ya figured things out with a slide rule and not a calculator, although I won't go back to one. Used a plastic caliper for a number of years untill a freebe dial one came along. (as a side note to ya, bet my baked beans and chili could win a purple ribbon and get a nod of approval from ya). And Mako, always since I've been logging on to the Cas Forum, have always enjoyed your posts/replys, always have learned a great deal of knowledge that some how has escaped me over the years, even like your long ones. Thanks for the 'Caliper 101' class, didn't know all of the "in's and out's" about calipers, knew how to use them, but not the real inner workings. Thanks much. Quess I'll keep looking into the digital deal. Good hearing from each of ya, thanks much.

[Cuts Crooked]

And Mako, always since I've been logging on to the Cas Forum, have always enjoyed your posts/replys, always have learned a great deal of knowledge that some how has escaped me over the years, even like your long ones.

Crow Choker, Thanx fer YOUR reply above!!!! And your contributions to our forum!!!! We have a lot of very good posters here, like Mako, Del, and others, youself included!  I like to see thier input acknowledged (hoping it keeps them posting if we occassionally massage their egos!  ) They may not always agree, may sometimes disagree vehemenatly, which is not unusual because there are many paths to The Darkside, but they are a great source of information even for an oldtimer like myself, who once thought he knew all there was to know about loading BP........

[Sir Charles deMouton-Black]

For Canucks;   CANADIAN TIRE has digital calipers for CAD13.99 on sale until 8 April.  Look exactly like the ones I got from Princess Auto for about the same price.

[Dalton Masterson]

I have used the digital cheapy from Midway for about 3 years or so. It has been good, and I still havent used up the battery. Midway had them on sale last month for 12 bucks or so, and I was gonna get a couple more of them to keep around in different shops I frequent.
DM

[Sir Charles deMouton-Black]

Harbor Freight has a coupon in the current issue of Popular Science.  $9.99 for 6 inch digital calipers, regular $29.99!

[Crow Choker]

Hello to the CAS'ers: Was revisiting this post from seven years ago as I had put it on my favorite list so as to go back and read Mako's 101 class on the workings of a digital caliper (where are ya Mako-come back on board-miss your informational 101's). Forgot this post was there. As I penned in my last post, I was curious as to the accuracy of my dial caliper given to me. I knew it was fairly accurate as I did measure some item's that had a given dimension. I did buy a Lyman digital and have loved it ever since. I did a bunch of measuring of a lot of things and found that thee Ol' Enco dial caliper given to me back around 1990 was 'spot on' with the digital rig. I use both now, but the .001 lines on the dial, well as for me, sometimes I say to myself is that reading 1.222 or 1.223. Have a eye exam coming up-hope that rectifies that. Anyway, always good to go back and read yesterdays news.
As a side note, the caliper came with two batteries that lasted for a good time, but I've only purchased batteries once for the caliper and still have the 2nd battery that came in the blister pack unused.

[Abilene]

Harbor Freight has a coupon in the current issue of Popular Science.  $9.99 for 6 inch digital calipers, regular $29.99!

Harbor Freight's "regular" price statements are usually vastly overpriced, to make their low prices seem even better.  But I do have a Harbor Freight 6" digital caliper and it has been fine.

But I keep an inexpensive dial caliper (from Midway about 15 or so years ago) as a backup.

[greyhawk]

Harbor Freight's "regular" price statements are usually vastly overpriced, to make their low prices seem even better.  But I do have a Harbor Freight 6" digital caliper and it has been fine.

But I keep an inexpensive dial caliper (from Midway about 15 or so years ago) as a backup.

Hmmm - I used to have a ruler to measure stuff - then I got an old lathe - had a buddy about that time had a mitsutoyo digital caliper - so I (being a cheapskate) bought an economy version, his was aboot $250 at the time - I think I paid maybe half that and got good use from it - eventually that one conked out - I got another cheapie - then another recently - somewhere in there I got a little micrometer and it lived in the tool storage drawer (me being a ruler person and all) cuz I thought I was doing fine with the caliper - I bought a bit better lathe for small work and maybe two tyears ago inherited (from an uncle) a decent lathe with some tooling - and a set of micrometers up to 6" (quality brand stuff) - started fooling round with more involved gun related work - resizing / swage dies for boolits, made a few reamers (3 is a few?) , in the process of that I taught meself basics with the micrometer and I realised what I was doing with the caliper was not good enough for fine work - I still use the digital a lot - and would not entirely blame the instrument for the difference (or not all of it anyway) but for me there is about the same (increased) level of effectiveness stepping from caliper to micrometer as there is moving from ruler to caliper - others may find differently and thats ok .
ps caliper $250 then $125 then $60 then $30 - I expect the next one I get they will pay me to remove it from the store?