Dial Calipers - Digital Calipers - Vernier Calipers
For what it's worth 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. That said, let's talk about the more popular dial calipers... 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. 
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. 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. 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 o nly 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 above. (1.370" is the correct answer.) By the way, is it caliper or calipers? The usage is usually in the plural: a pair of calipers. As such, it will use the singular verb: a pair of calipers is indispensible. | Quality in General |  | | | | Dial caliper quality has deteriorated over recent years because all the manufacturers are trying to keep up with the low prices of Chinese imports. That's too bad, because there will always be tool-and-die makers, devoted hobbyists and other professionals who'd be willing to pay more in order to get a really fine tool. It has become impossible to find anything that's truly worth the appellation "quality." Every manufacturer has disappointed in one way or another and so we find it hard to give enthusiastic thumbs up to any brand in particular. | Dial Calipers Brand Comparison | | | | | Brown & Sharpe dial calipers are made in Switzerland. 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. The quality of these calipers has deteriorated somewhat over the past few years but they're still among the best available. Chicago Brand dial calipers are sold by a California company. They're made in China. - Sales: distributors of Chicago Brand
- Repairs: not possible
- Parts: not available
- Information: the Chicago Brand web site
Etalon dial calipers were the royalty of the line. Unfortunately, these aren't what they used to be. Both workmanship and quality have suffered noticeably. They are made by the same manufacturer who makes Brown & Sharpe and Tesa calipers. 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. - Sales: Fred Fowler Company and major catalogs
- Repairs: not possible
- Parts: not available
- Information: contact the Fowler Company
Helios dial calipers are a discontinued brand made in Germany. Originally, they were copies of the Etalon calipers. Several models are still available from Fred Fowler Company. - Sales: Fred Fowler Company for some models
- Repairs: no longer possible
- Parts: not available
- Information: no longer available
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. - Sales: directly from Mahr-Federal
- Repairs: contact the manufacturer
- Parts: availability is unknown
- Information: catalog available from Mahr-Federal
Mitutoyo dial calipers are assembled in Brazil, metric versions in Japan. The beam is coated—a new innovation—so that it doesn't easily wear down with repeated use. We've repeatedly noticed mechanical difficulties in some new models made in Brazil. If the gage has "jumped a tooth" then zero setting is not possible without disassembly on these 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. - Sales: Fred Fowler Company for some models
- Repairs: no longer possible
- Parts: not available
- Information: not available
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. - Sales: catalogs
- Repairs: not possible
- Parts: not available
- Information: none
Scherr-Tumico (S-T Industries) dial calipers are made in China, for the most part. - Sales: S-T distributors nationwide
- Repairs: uneconomical
- Parts: not available
- Information: S-T catalog
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. One model of 6" calipers (1202A) is clearly made in China (but made of harder steel, so it's actually a better gage). Buy Starrett for the name but not for the quality. The crystal and bezel assembly can be purchased and installed without much trouble if you ever need to replace the plastic lens. (See spare parts list.) - Sales: Starrett distributors nationwide
- Repairs: click here
- Parts: click here
- Information: Starrett on-line catalog
Tesa dial calipers are made in Switzerland, of exactly the same parts used for Brown & Sharpe and Etalon calipers. The workmanship has deteriorated noticeably over recent years probably in an effort to keep prices competitive. If you're used to the top quality of old Tesa calipers, you may be disappointed in the new models. It shouldn't discourage you from buying this brand however, it's still among the best available. And, if you can get hold of an old model on eBay, grab it. | Digital Calipers Brand Comparison | | | | | 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. 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. Anyi digital calipers are made in Guilin, China (a picturesque landscape town in the South). Quality workmanship has arrived in China and these calipers are every bit as good as their European or Japanese equivalents. This new company started production in 2005 so it may be a while before you see these tools. - Sales: not yet available
- Repairs: not yet available
- Parts: not yet available
- Information: contact the manufacturer via their website
Brown & Sharpe Shop-Cal is actually a Tesa digital caliper, bearing the B&S name. These are low cost digital calipers of good quality made in Switzerland. Etalon digital Basic-Cal is very easy to read with no skill required. These Swiss-made digital calipers are probably the best of the "throw-aways." They're so affordable that if they ever stop working, you simply replace them. Recommendable for their simplicity. This model is being phased out and replaced by the Tesa Shop-Cal. Mahr-Federal digital calipers, made in Germany. Some models have wire-style depth rods. The beam doesn't have any numbers on it so you won't be able to "ball-park" your measurement. Repairs are probably uneconomical. The manufacturer doesn't encourage repairs. In the words of one of their salesmen:"let 'em buy a new gage." - Sales: directly from Mahr-Federal or major catalogs
- Repairs: usually not economical
- Parts: too expensive or not available
- Information: Mahr-Federal has a web-site
Mitutoyo digital calipers, made in Japan, are the most sophisticated of the bunch. Word has it that these are a major improvement in digital tools. Mitutoyo is always introducing new features. Unfortunately this makes last year's model obsolete and repairs may not be possible. This is a drawback considering the price of some of this equipment. A useful innovation is the solar-powered digital caliper which is ideal for researchers and technicians "in the field" or on the road. A word of caution: spare parts are currently not available because of legal hassles. NSK digital calipers are made in Japan and distributed in the US by Fowler, among others. We have no experience with these. - Sales: Fowler distributors nationwide
- Repairs: contact your distributor
- Parts: unknown
- Information: unknown
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. - Sales: Flexbar distributors nationwide
- Repairs: return to Flexbar (New York) for servicing
- Parts: common parts are stocked by Flexbar
- Information: Flexbar at 1-631-582-8440
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 $45 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. - Sales: catalogs and Fowler dealers nationwide
- Repairs: we'll return these to the factory for servicing, but don't expect miracles
- Parts: generally not in stock
- Information: Fred Fowler catalogs
Tesa digital calipers, made in Switzerland, come with IP65 dust and water protection. This is a pretty high rating and these calipers may well be what's needed in certain environments. Tesa calipers in general are of the highest quality available but repairs are often not possible since parts may not be available. You also won't have much of a choice as far as SPC output goes. Choose this brand if you have an affinity for precision tools from Switzerland. | Vernier Calipers | | | | | 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. | Plastic Caliper | | 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. Digital plastic calipers are easy to use and can switch between inch and metric. Swiss made models may be the best available, with an accuracy of .004", and are featured on page 160. | 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, these dial calipers can be brought back to manufacturer's specs. Our fixed repair prices are shown on page 30. In some cases you may find this is more than half the cost of a new tool, but consider this: it's still less than a new one. Your satisfaction is guaranteed. Digital calipers with electronics problems are probably too expensive to repair. We'll return these to the factory where, in some cases, you may be offered a new trade-in or a factory-rebuilt replacement. Brown & Sharpe, Tesa, and Etalon dial calipers are virtually identical. They're made by the same manufacturer. All parts are available and interchangeable. Quality dial calipers made by Mitutoyo and Starrett can also be repaired for the same reasonable price which greatly extends their useful life. We have all spare parts in stock. 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." What if just the crystal has popped out, or the end-stop or battery cover is missing? You can probably deal with this yourself. You'll find a parts list on-line, and instructions for many projects are available at Do-It-Yourself. | Caliper Care | | | | | 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. Dial caliper calibration instructions as well as calibration standards are available on page 7. | So you want to read fractions? | | | | | 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". | More About Calipers | | | | | - Calibration Procedures page 7
- Brown & Sharpe dial calipers and alternatives page 11
- Repair service including warranty repairs page 30
- Starrett calipers page 32
- Tesa metric dial calipers page 97
- Tesa digital electronic calipers waterproof page 98
- Brown & Sharpe calipers accessory set "Centerline Plus" page 102
- Brown & Sharpe dial calipers made in Switzerland page 103
- Etalon dial calipers page 105
- Etalon professional metric vernier calipers page 106
- Depth measurement with dial calipers page 112
- Mitutoyo solar powered digital caliper page 127
- Mitutoyo digital "Digimatic" calipers page 135
- Brown & Sharpe vernier calipers for professionals page 136
- Mitutoyo dial calipers page 140
- SPI digiMax Swiss made plastic digital calipers page 160
- Depth base attachments page 173
- Brown & Sharpe Shop-Cal digital calipers page 185
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