The 10 Best Dial Calipers
This wiki has been updated 23 times since it was first published in March of 2016. Dial calipers are precise measuring instruments used in both hobbies and professional settings, such as woodworking, auto repair, machining, and manufacturing. Capable of reading the inner and outer dimensions of fittings and clearances, as well as depth and incremental (or step) values, they're essential tools for ensuring that your parts fit together and adhere to accurate tolerances. When users buy our independently chosen editorial selections, we may earn commissions to help fund the Wiki. If you'd like to contribute your own research to the Wiki, please get started by reviewing this introductory video.
January 24, 2020:
Removed the iGaging 100-164 in favor of the Mitutoyo 505-742.
Calipers, particularly dial calipers are high-precision instruments that require several features to be truly reliable. The sliding surfaces, jaws, and beam must be ground to very fine tolerances and checked for flatness in order for these parts to produce accurate readings. The higher-quality models like the Mitutoyo 505-675-56, the Starrett 1202F, and the Brown and Sharpe 599 have a noticeably smooth action because of the accuracy of their machining and the coating on their surfaces. The thumb screw action for them is extremely fine to help with small adjustments.
If you want a decent set at a modest price, the Shop Fox D3208 and the Anytime Tools 100-020 both offer surprising quality at about half the price of the professional models. While they won't operate as nicely as the high-end models, once calibrated with undamaged gauge blocks, they'll offer accuracy within a thousandth of an inch, which is plenty accurate for almost anything they can be used for.
When working on critical parts, it is always advisable to check your calipers against a known surface such as a gauge block.
Dial It Back A Couple Millennia
While he refined the concept, there's a good chance that the Chinese used a distinct precursor to these breakthrough tools at least 1,000 years earlier.
Dial calipers have a surprisingly rich and multicultural history for a seemingly simple tool. The first tools known as calipers closely resembled the compass known to geometry students everywhere. These tools have been around for over 2,000 years, showing up in shipwrecks from as long ago as the 6th century B.C.E. It's believed that their principle uses were navigation and cartography, rather than measuring solid, real-world objects.
The well-known Vernier calipers are named after French mathematician and tool guru Pierre Vernier, who added a second, finer scale to the existing sliding-jaw measurement tools. While he refined the concept, there's a good chance that the Chinese used a distinct precursor to these breakthrough tools at least 1,000 years earlier. The Chinese hold these nogisus in high regard; in antiquity they crafted precious, jewel-adorned models at the request of their rulers, and particularly old or historic specimens are kept in cultural museums.
Between 200 and 300 years after Vernier's redesign, most sliding-jaw calipers transitioned to a scabbard-style construction, in the which the upper jaw protruded from a sheath fixed to the lower jaw. This significant advancement reduced side-to-side play, thus increasing precision, and made it easier to read the scales accurately.
In the mid-19th century, two Americans from New England would make further improvements to the caliper, for the first time offering consistently high accuracy from a reasonably priced tool. Joseph Brown's 1851 model was the first to ever read to thousandths of an inch, while his overall refinements made it possible for anyone to afford a reliable Vernier caliper.
In 1883, Massachusetts watchmaker John Logan developed the first dial gauges, first using a length of chain that wound around an internal drum, and ultimately settling on the rack-and-pinion design that many dials use to this day. By the turn of the 20th century, people started to realize the benefits of the improved depth gauges and began to implement them into all aspects of industry, including high-precision measurement tools.
Newer Isn't Always Better
Like any other unassuming, straightforward tool in the 21st century, calipers are now available with a bevy of electronic bells and whistles. Back-lit readouts, multiple measurement dimensions, and various selectable demarcations are some of the enticing features that may draw your eye at the hardware store. As with a lot of high-accuracy devices, though, a large contingent of seasoned pros swear by the analog version, and they have good reason to do so. The simple reliability of a physical dial that you can see and touch certainly doesn't hurt. And while that dial isn't quite as durable as a solid-state chip, it is repairable. On the other hand, if your battery-powered model goes on the fritz, you may as well just get a new one — there's usually no fixing things like that.
Two of the most important advantages to real, tangible measuring scales are moisture resistance and visibility.
Two of the most important advantages to real, tangible measuring scales are moisture resistance and visibility. LCDs are great if you're looking straight at them in good light. Move to a dim work site, and stretch your arm around some machinery to take a reading, and you'll almost certainly benefit from an old-school tool. Analog types aren't 100 percent waterproof, but they're safe in high humidity and they can usually take a couple splashes. They're also less susceptible to high temperatures. Many consist of extremely hard, forged alloys and scratch-resistant glass, which can minimize shock damage as well as expansion due to heat. The last thing any technician needs is a sensitive circuit board falling prey to a still-hot fitting during an expensive job.
Overall, dials offer an upgrade over the standard Vernier design primarily because they're more accurate and easier to read. That does raise the price over the simpler, linear variety considerably, but the right brand of calipers should realistically last for many years. Of course, they are made of small mechanisms that can be vulnerable to dust and oil, so it's important to take good care of these instruments. Also, for what it's worth, dial calipers are intended mostly for medium to small jobs, and you'll rarely find them in lengths longer than about 12 inches.
Time To Get Dialed In
It's pretty well-known that people who often use tools also tend to get very passionate about them. Calipers, which see quite a bit of use on some job sites, are no exception to this rule. There are (as with most modern tools) a lot of brands to choose from, some new, and some old. It's not a hard and fast rule that older companies make better products, but names such as Starrett, Mitutoyo, and Brown & Sharpe have been around since the caliper was first popularized, and still produce some of the most beloved options today.
Depending on your needs, various dial colors deliver great visibility in adverse settings like high humidity or low light.
Most consist of roughly the same parts, starting with large and small jaws for typical outer and inner measurements. They very often feature a stop screw, to set the slider in place, and some have a thumb-operated screw that makes minute adjustments easy and accurate. A depth rod sometimes protrudes from the bottom of the sheath, and, of course, there are measurements down the tool's body leading to the always-prominent dial. Depending on your needs, various dial colors deliver great visibility in adverse settings like high humidity or low light.
Technically minded people from trained scientific researchers to self-taught DIY enthusiasts have reason to take exacting measurements from time to time. The right caliper will definitely help with this cause, although there are two important caveats. One, you often get what you pay for; if it will see daily use, or if safety or big-budget projects rely on it, be sure to choose a reliable, high-end unit. On the other hand, the average hobbyist can usually get by with a less expensive version, although they do vary greatly in quality. Most importantly, remember the accuracy and precision of a measurement rely very much on the skill of the person taking it. Now go out there, and have fun measuring!