For what it's worth
Dial calipers are like vernier calipers with a dial. This makes it easier to read for some people. The vernier scale can be small and you may have to resort to glasses or even a magnifier to read your vernier. The dial is pretty large and you probably won't have to squint to take a reading. While dials may be an advantage, it causes all sorts of problems. For one, all those gears and parts will eventually malfunction. Count on it.
For another, having a dial limits the calipers to being either metric or inch reading. That's no problem if you never need to switch systems. One or two models have attempted to combine both systems on one dial but that's confusing and bound to lead to errors.
Dial calipers offer four measuring capabilities: outside dimensions—such as diameters—measured with the large jaws, inside dimensions measured with the smaller jaws, depth measurements obtained with the extending rod, and step measurements taken with the front of the tool.
An optional Centerline Accessory Kit will also allow you to easily measure distances (center to center) between holes, groove diameters and undercuts where the jaws alone would be unable to reach.
Before we start, let's state outright that the best, most reliable, and most useful caliper you can own is a vernier caliper. It isn't electronic and it doesn't have a dial. Only seasoned pros are likely to own and use the vernier calipers. That said, let's talk about the more popular dial calipers...
The ends of the jaws are beveled so that measurements in slots and grooves are possible. Don't use this area of the jaws for general measuring however, because it wears down quickly. Measure with the flat area of the jaws whenever possible.
We used to advocate against getting calipers with carbide jaws but have had second thoughts. The calipers that come for repair always have badly worn jaws and the user rarely sees this as a problem. It is a problem: it can easily mean errors of .001" or more. However, carbide jaws have the disadvantage that they will chip easily, this being the nature of carbide. Broken carbide jaws can not be repaired. Particularly vulnerable are the sharp tips on the ID jaws. If you think that you can be reasonably careful, then we suggest investing in carbide jaws for more reliable readings.
The depth measurement is fine for small diameter holes and can extend all the way to 6 inches. If you need to span a larger diameter hole you can always get a depth bar attachment which will make your caliper function somewhat like a dial depth gage (see below).
Calipers have .001" graduations and are accurate to ± one graduation (per 6") if none of the measuring surfaces have been worn, bent or damaged. They're perfect for all sorts of quick measurement and can be used as a preliminary source before moving on to more sensitive tools such as micrometers (.0001"), depth gages or dial indicators (.0005" and .0001").
Calipers should be frequently checked for accuracy using a gage block, or gage block combinations. To check for wear in the jaws do this: clean them and close them. Then hold them up to the light and if they're worn you'll see light shining through the gaps. At this point, measure with the unworn surfaces or have the calipers repaired. These jaws can be ground flat again. See calibration instructions on page 7.
The most common dial calipers have a measuring range from zero to six inches. These are the most useful because they can be easily handled. However, 8-inch, 12-inch, and even longer calipers are available. Be advised that it is nearly impossible to take readings near the end of the ranges of these calipers. They become awkward and clumsy to use. On a 6" caliper any readings above four inches are likely to cause you trouble. You should use the next larger calipers in these cases.
The inclusion of the dial makes for much easier reading because it eliminates the need to know how to read the vernier scale. The invention of the vernier scale is one of the unsung innovations of the past, but reading the scale requires some training and a lot of practice if you want to be proficient at it. It's best to ask someone to show you how to do this.
When taking a measurement, close the jaws only lightly, with pressure that is consistent from one reading to the next. You'll soon see that it's possible to fudge the results by just pressing a little harder. You don't want to do this. If you're new to calipers, it may be a good idea to practice on a gage block for a while to make sure you can get repeated measurements.
For quick reading, combine the numbers in A-B-C order, as shown. (1.370" is the correct answer.)
The usage is usually in the plural: a pair of calipers. As such, it will use the singular verb: a pair of calipers is indispensable.
Brown & Sharpe dial calipers are made in Switzerland to some degree (see note). They are available with silvery-white or black dials. These very popular calipers have extra hard stainless steel jaws which gives them a long useful life. Spare parts are readily available. (Obsolete model 578 was made in Germany at the time. Parts are no longer available.) If they have a problem it lies in the fact that the cover unit is a press fit onto 4 rubber plugs. Once you remove the cover unit, these plugs are likely to become damaged and the cover may no longer fit securely. If you notice a loose cover, this is likely the cause. You will also find that it is very awkward to remove the crystal and to install a new one (although if all goes well the new crystal presses in place without any tools required).
Brown & Sharpe Valueline dial calipers made in China. These are so remarkably well made that they actually compare favorably to their Swiss-made cousins. Although we cant be certain about every part, but it looks like you could repair these using the Swiss parts. For the price—about half—these are a bargain and can be treated as throw-aways. We will not sell these, however, since we have a bone to pick with China and their repressive regime.
Chicago Brand dial calipers are sold by a California company. They're made in China.
Etalon dial calipers are made by the same manufacturer who makes Brown & Sharpe and TESA calipers. The pros and cons are the same. Labeled "Swiss Made" although the caliper body is of Chinese origin.
Flexbar sells nameless calipers of Chinese origin, along with some better known brand names such as Preisser. If the country of origin is not specified, it is usually Chinese. They offer a black face dial caliper which is somewhat similar in appearance to the Swiss made Brown & Sharpe models..
Fowler dial calipers are a vanity brand. Fowler simply puts its name on generic calipers usually made in China. If you see a logo that looks like a seagull's wings then the brand is Aerospace which is most certainly of Chinese origin. These ought to be very cheap to buy because that's what they are. Spare parts are never available which means that even simple repairs are impossible.
Helios dial calipers are a brand made in Germany currently owned by Mahr. Originally, they were copies of the Etalon calipers. Several models are available in the US market from Fred Fowler Company, among others.
Mahr-Federal dial calipers sold with the name MarCal. We haven't seen any of these so can't offer any information. It appears that only 6" mechanical versions are available, and these have black dials.
Mitutoyo dial calipers are assembled in Brazil, metric versions in Japan. The manufacturer is forced to change model numbers every few years in order to stay ahead of the Chinese who imitate these calipers without shame. Imitations often have only two decimal place readout, and the certificates of calibration have serial numbers which do not match the gage. Be sure to buy from an authorized Mitutoyo distributor (this includes Amazon.com as long as "sold by Amazon" is stated on the selling site). If the gage has "jumped a tooth" then zero setting is not possible without disassembly on the Brazilian models.
NSK dial calipers are made in Japan. Some models are available from the Fred Fowler Company which has put its own name on the calipers.
Peacock dial calipers are made in Japan and spare parts are not available. Repairs are probably not worth the effort since parts may be involved. Since we don't repair these, we have no opinions or useful information. Buy Brown & Sharpe instead.
Preisser (Germany) makes a line of highly professional vernier calipers with measuring capacity of up to 120 inches. These are distributed in the US by Flexbar.
Scherr-Tumico (S-T Industries) dial calipers are made in China, for the most part.
Shars (China) spare parts and repairs will not be available for gages made in China.
Standard Gage (China) by Hexagon Metrology, newly introduced in 2009. "Globally Sourced" is the way Hexagon describes these cheap calipers. We're supposed to guess what part of the globe they come from. Duh.
Starrett dial calipers have a marked disadvantage. The metal is soft and bends easily under heavy use. The jaws quickly become misaligned and errors appear. Plastic parts have shown up on recent models and no one is impressed. It is not clear where these are manufactured, but Starrett would like you to believe it's here in the States. Series 1202 is clearly made in China, made of harder steel, and in several ways an improvement but parts for these Chinese models can be hard to get. For the American models, the crystal and bezel assembly can be purchased and installed without much trouble if you ever need to replace the plastic lens. Buy Starrett for the name, not the quality.
TESA dial calipers are labeled "Switzerland" but are assembled in China, of exactly the same parts used for Brown & Sharpe and Etalon calipers. If you're used to the top quality of old TESA calipers, you may be disappointed in the new models. And, if you can get hold of an old model on eBay, grab it. The "Eagle" model has titanium coated beams (refer to our repair section below).
Batteries required? Although the jaws can also be ground flat and parallel on digital calipers, we run into the added problem of electronics. These parts are usually too expensive to replace. Furthermore, the models change every couple of years making them obsolete. Sad to say, digital calipers by all manufacturers should be considered a short-term investment. (By the way, batteries and battery covers are available. See our parts list.)
Nowadays, digital calipers are quite inexpensive and often are of better construction than their mechanical counterparts. If you can get used to pushing buttons, these are much easier to read than a dial. That's definitely an advantage to a beginner. Also, because they don't have gears or a rack, the digital calipers usually offer a smoother feel.
In the case of Mitutoyo digital calipers, where parts are available, do-it-yourself repairs are as easy as unscrewing a couple of Philips heads. Reading unit replacement is a cinch.
If you don't have a preference we'd say "go digital" and avoid the bells and whistles if you don't need them. Solar powered calipers are an environmentally friendly alternative to our gluttonous use of batteries and can be highly recommended.
Brown & Sharpe Twin-Cal is actually a Swiss TESA digital caliper, bearing the B&S name. An optional connector replaces the battery and easily allows you to connect to your PC. However, expensive software made by TESA will be required. The "Valueline IP67" does not have SPC capabilities.
Mahr good quality digital calipers made by Mahr, the German manufacturer, at their factory in China. Generally sold under the name MarCal. Some models have wire-style depth rods. Thumb rollers are optional. The beam has large, easy to read numbers on it so you can "ball-park" your measurement. They glide smoothly on the beam. With "MarCom" all Mahr measuring instruments with MarConnect interfaces RS232, USB or Integrated Wireless can be connected; simply outfit the measuring workplace with USB Hubs.
Mitutoyo digital calipers, made in Japan, are the most sophisticated of the bunch. Mitutoyo is always introducing new features and as a result, models change frequently. They can't be beat for SPC data collection which can be as easy as a USB cable and an Excel spreadsheet. Mitutoyo is the only manufacturer that makes replacement reading units readily available for a very simple–although still costly–fix when the electronics go bad. Often times, the end user can perform these repairs if s/he's not a total klutz. A useful innovation is the solar-powered digital caliper which is ideal for researchers and technicians "in the field" or on the road.
NSK digital calipers are made in Japan and distributed in the US by Fowler, among others. We have no experience with these.
Preisser digital calipers are made in Germany and distributed in the US by Flexbar. Preisser Digi-Met IP65 calipers use Swiss-made Sylvac electronics whereas the new IP67 calipers, Prisma and Data Variable manufactured by Preisser were realized in cooperation with Mahr (Germany) and bear electronic chips developed by Mahr. We have no experience with these calipers. Flexbar provides some repair service but admits that gages often need to be returned to the factory in Germany, an expensive and time-consuming process.
Standard Gage (China) 2009 new introduction from Hexagon Metrology who apparently is no longer able to resist the lure of communist labor. But then... look who's buying!
Starrett digital calipers have been seen coming off the assembly line in China but what else is new? We have no experience with these models. We are, however, impressed with the quality and speed of repair service when digital gages are returned to the manufacturer. This is quite possibly the only manufacturer in the US with a reliable repair department for their digital products; however, they'll charge you $$$ just for a quote.
Sylvac digital calipers, made in Switzerland, distributed in the US by Fred Fowler. This is sophisticated equipment with many variations. As with other electronic equipment, if it fails it will probably not be repairable. On the plus side, most of these come with a 5 year warranty, something which no other manufacturer can offer. It sounds good, but that's a warranty on manufacturing defects. It doesn't cover the damage caused when you drop the gage.
TESA digital calipers, made in Switzerland, are identical to Brown & Sharpe (see above).
These precursors to the dial calipers can still be found in the hands of skilled tool makers. It requires mastery of reading the vernier scale. The most obvious advantage? No dial, no movement, nothing to break. The disadvantage? Generally more expensive than their dial sporting cousins, probably because it's costly to engrave all those little lines and numbers. These calipers probably never need repair, so the extra cost may be worth it. It'll also make you look truly professional (try not to have an appearance of superiority).
The vernier caliper is the tool of choice. They're the ones we use in our shop and with more than 40 years of use, they're still working perfectly.
They have the advantage of combining the metric and inch system in one tool. Simply read the top scale for millimeters or the bottom scale for decimal inches. (Digital calipers can do the same thing, but they need batteries, and we'd like to see one of those last 40 years!)
Modern vernier calipers have adjustable vernier scales. You will notice several screws which can be used to move the scale minute amounts back and forth. Please don't play with these screws. If the jaws ever need to be reground, straightened or lapped, then the movable vernier will have to be adjusted so that zero coincides. In earlier days, these scales were not adjustable which meant they were useless once the jaws were out of whack. Unfortunately some of the Etalon vernier calipers (00519087 for example) still fall under this category.
To say that they're useless is a bit severe, though. A vernier caliper does not suffer from incremental errors. Therefore any error which shows up when the jaws are closed will be the same error at any other point along the beam. When the jaws are worn, your zeros may no longer line up. You may have a negative reading. If, for instance, you read 0.95 mm on your vernier scale then you have a 0.05 mm negative error. (Subtract 0.95 from 1 to get this result.) You can now use the vernier caliper as long as you always subtract 0.05 mm from your results. A good idea would be to label the calipers so that you'll be reminded of this fact.
If you are investing in a vernier caliper, by all means buy a quality product such as Swiss-made Brown & Sharpe or Etalon. Unfortunately, these calipers have become so old-fashioned that most models have been discontinued.
Most digital plastic calipers are of Chinese origin. They are easy to use and can switch between inch and metric.
Plastic dial calipers (and plastic vernier calipers) do not have the accuracy of the metal calipers even though the dial readings are the same as their precision counterparts. Some plastic digital calipers have an accuracy of only ±.008" which would never be suitable for precision work in a machine shop. Plastic dial calipers are suitable for woodworking, model building, and hobbyists in general. The plastic jaws will not mar delicate surfaces and for that reason are ideal for antiquarians, numismatists and biologists who don't want to accidentally damage their specimens.
If you can find them, Swiss made models may be the best available, with an accuracy of .004", and are available in some catalogs, including SPI. We do not sell these.
We have come to the conclusion that it is no longer economically feasible for us to offer any caliper repairs.
Besides replacing worn parts, the surfaces of the jaws need to be reground so that they're flat and parallel again. Although labor intensive, in the right hands, these dial calipers could be brought back to manufacturer's specs.
You could buy appropriate parts and give it a go yourself, if you have a lot of time on your hands and don't mind giving up in defeat on occasion. Otherwise, shop around. There are still repair shops which will accept calipers for repair.
Digital calipers with electronics problems are probably too expensive to repair but usually all that is needed is a replacement reading unit. These are easy as pie to replace and Mitutoyo, at least, has many of these parts available for the do-it-yourself crowd. Check our parts page to see if reading units are available for your particular model.
Brown & Sharpe, Tesa, and Etalon dial calipers are virtually identical. They're made by the same manufacturer using the same parts. All parts are available and interchangeable.
Some calipers now come with "coated" jaws which means they don't wear down as quickly; but, if you drop the calipers or hit them from the side the jaws will still become misaligned. It is not possible to lap the coated jaws and a repair may not be possible in this case.
Spare parts for Helios, Peacock and Kanon dial calipers are generally not available and these models may not be repairable.
Inexpensive models, including imports from China, should be treated as "throw-aways." In fact, they should probably have been thrown away before they were bought. But, we are a bit biased in that direction.
Even brand new calipers may exhibit some roughness in movement. You are usually feeling the gear teeth as they travel along the rack. This is normal. As mentioned above, dial calipers are no longer what they used to be. Wipe the beam before each use to avoid getting dirt or chips into the rack teeth. Do not oil them because that only acts as an adhesive for dirt particles.
Dirt and dropping, or hitting them, are the major nemesis of the dial calipers. Use an air hose to blow away chips and grinding dust, and do this very often. Pay particular attention to the teeth in the exposed rack. Do not disassemble the calipers. You'll have a heck of a time trying to get it to work afterwards. Do not squirt or blow any solvent into the dial movement. It will probably only gum up the works.
If you work in an environment prone to rusting, then the exposed steel of some calipers (Starrett for example) may benefit from a very light coat of oil such as WD40, wiped off with a cloth. Most calipers are stainless and should not be affected.
Digital calipers must have clean and dry beams to function correctly. The beam should be wiped with a soft cloth. Oil or water must be completely removed if the display shows an error. When you receive a brand new digital caliper, the instructions may tell you to clean first, with an oil-soaked rag. These calipers have been coated with a grease for shipping and storage purposes. Remember, many of them come by slow-boat across the Pacific. Let's not go crazy about the oil-soaking, but take a clean cloth and some WD40 and wipe off the exposed metal parts: the beam and the jaws. Leave all plastic parts alone. Then take a dry cloth and wipe off the WD40. Now you should be all set.
Are you smarter than the average 5th grader? You will still find vernier calipers with fractions of inches and learning to read them requires more math than skill. It's easy to make errors, but here goes:
Look at the zero on the upper scale. Take note of the line which it has just passed on the lower scale. These indicate 1/16 of an inch. For example, it may have just passed the 1-1/16" mark. Now find the spot where the upper and lower scale lines coincide. At this point, the upper line will indicate how many 1/128ths need to be added to the 1-1/16". If this is the number 4, for example, you will have to add 4/128" to 1-1/16" ... we'll leave you to do the math although we believe it adds up to 1-3/32".
Starrett makes it easy by printing the fractions directly on the dial. It is the ideal solutions for wood working and other inch reading applications. One caveat: This Starrett model 1202F-6 dial caliper is made in China.
Q: I am trying to locate a quality set of 6 inch digital fractional calipers. I have found a caliper from Fowler, SPI, Wixey and others. Mitutoyo and Starrett don’t offer one. All the reviews I’ve found on every company's calipers are mixed and contradictory. I don’t know what to believe. I would be using the calipers for woodworking, table saw set up, drill bit sizing and light metal work.
Large diameters, say 10" are not conveniently measured with calipers. The jaws would have to be at least 5" long and holding a large caliper is a two-person job.
It would be better to use a micrometer. Any micrometer would have a throat depth large enough to measure the diameter of a rod within its range. And, you can probably do it without anyone else's help.
It should come as no surprise that "made in…" doesn't always mean the entire gage has that country of origin. In fact, we can pretty much assume that at least some parts of ALL calipers will have Chinese origins. [If any manufacturer can prove otherwise, please let us know!] By Swiss federal law, for instance, a gage can be labeled "Swiss", or some variation of it, as long as at least 60% of the material is of Swiss origin and that final manufacturing was made in Switzerland.
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