Top Digital Calipers for Machinists (2021)

Good luck buying a Mitutoyo from eBay that isn't a fake. I won't buy measuring tools from anything except a factory authorized retailer anymore.

I usually prefer analog-everything but I always found dial calipers to be extremely drop-sensitive. Like a "shock-proof" set from work developed wiggly-needle syndrome after being dropped about 6-8 inches onto a sheet metal desk and could never really be zeroed perfectly again. By contrast a $30 digital set from Lowes or HD got flung into the concrete by a falling part and was still accurate to a few thousandths at least. (I did notice the "inside" gauges have slight variance between brand new pairs though, so the manufacturing tolerances probably aren't the best)

Starrett and Mitutoyo are good enough to build planes and rockets on a professional level.

yep, exactly my experience. I've almost never seen non Mitutoyo calipers anywhere that's not a personal/hobby shop

>I really wish someone made a set of micro-vernier calipers that are small enough to fit on a keychain.

I'd really like to know what you mean by that. Obviously the Vernier scale can't shrink, so you're going to be limited to an inch or two of range, and all the sharp edges common to calipers aren't pocket friendly.

Something fold-up, or that has a few pieces to snap together?

As a fellow FDM printing amateur, tools most used are:

- digital caliper. The ultimate reference measurement device.

- feeler gauge. To check bed levelling but also prints.

I hadn't considered a profile gauge but will now look into it. Thanks!

For some of these, like the $80/6" Shars caliper that you can get from Amazon in 24 hours (most of the time), it's not even worth dealing with recalibration. If you no longer trust it, get a new one.

You can inexpensively (~$10) check if your calipers have been whacked out of calibration as frequently as you want with a gauge block or other calibration standard. If they have, you can also calibrate using the same block.

My problem with calipers is that there are three separate measuring modalities (outer, inner, depth) that can each require different zeroes as they get damaged.

I'd agree. With calipers and multimeters, I find having multiple so there's always one on-hand beats precision.

There is room for precision equipment on both fronts, but the number of times I need that level of accuracy is maybe 1% of uses. Having several is often handy. I often want to monitor several voltages at once, or have calipers locked to multiple lengths.

That's more general too.

Power drills and drivers too -- there are times for a really good hammer drill or what-not, but having one versus not having one is a much bigger difference, and on most projects, the convenience of having several is huge. If I have four, I can do a whole row of screws without swapping bits:

- 1/8 pilot hole for the bottom piece;

- 1/4 hole for the top piece;

- 1/2 hole for the countersink; and

- driver for the screw

Four cheap drivers beats one good driver.

Cheapest calipers often have wobbly jaws that makes the stated DRO precision of it meaningless. A quick check is to close them, reset the display and do a few full scale motions. You'll often see the zero is not maintained.

That's mostly the case. Anecdotal experience here has the cheap ones losing accuracy as the batteries drain, and of course when there's no notification of when your batteries are drained and not being able to actually turn them off, is a problem.

I could live with the cheapies if I had to, but buying a Mitutoyo or even that nicer Shars import brand (Aventor) is just such a huge quality of life upgrade. Except for Harbor Freight. I absolutely love Harbor Freight but I will never use another set of calipers from them. The accuracy loss as the batteries started to drain was just ridiculous.

there is a critical place that this is not consistent with the cheapies that the better ones get right: there are 4 ways to measure with a caliper - between the front jaws, outside the back jaws, the plunger on the bottom, and the ledge on the back/top. On cheap calipers these almost never match. On good ones they do. Buying the really bad ones from HF or similar doesn't necessarily produce inaccurate readings, but it means none of those 4 measures can be reliably compared.

I tested a pair of Harbor Freight calipers on a set of gage blocks at work, and they were accurate. They don't always drive exactly to zero, as one other post mentioned.

Something I did notice is that the newer Mitutoyo calipers at work have a much faster display update, making them considerably easier to use. They also had more smooth motion, though this is subjective.

For home use, bike repair, etc., the cheapies are good enough. Given that my colleagues prefer digital, I've got the cast-away dial calipers and am perfectly happy with them, plus an old Mitutoyo vernier at home that I use, just because.

I've bought cheap calipers from a discounter, and they're accurate to ~0.01 mm when compared to expected sizes of e.g. coins or measurements taken with a fancy caliper set I had access to.

I'm sure there are some downsides that would show with regular use, but for my hobbyist use case (occasionally take measurements, typically only needing to be accurate to something like 0.1 mm), they're more than enough. I've had one case where I needed sub-0.1mm accuracy and they also did that job perfectly.

Absolute scale would be a valuable time-saver though if I was using them professionally, and machinists probably benefit a lot from having coolant-proof versions.

I have a Mitutoyo vernier 6", an 8", and a cheap digital model.

The build quality on the Mitutoyo vernier 6" is so good that I always reach for it first. I also like its analog readout, and no batteries required.

The digital one has its uses - good if you need to do arithmetic, or compare to a DRO on another tool (like a planer, for woodworking).

Can confirm that my harbor freight caliper burns though batteries while off.. it is otherwise adequate.

That's one of the differences. Better metal is another; calipers used in anger will suffer wear and good ones last longer.

Calipers are something you want working when you reach for them. If you leave them in a box for a month and the batteries are dead when you need them it's a big frustration. I get about 2 years from Mitutoyo calipers used a couple times a week.

Buy once, cry once. The downsides besides the price is that you're a bit more circumspect about what sort of crevice or hole you're willing to poke it into and, like all good tools, once a thief knows you a set they never forget...

No. The accuracy of the encoder isn't the whole picture. The machining of the two blade pairs and the depth gauge are also important so that they all zero simultaneously. The cheapies also don't have absolute positioning.

Digital calipers do have the advantage of being much harder to misread, as well as the fact that you can do some neat math tricks with em. E.g need the center distance between two same-sized holes? measure the hole diameter of one, zero the calipers, and then measure the outside-outside distance of the holes. The caliper will read the center distance.

Some of the metalworker comments at the bottom of the page are useful, as were most HN comments. Links to better articles would be appreciated.

Unfortunately, while the Practical Machinist forums are excellent, their website itself is worthless.