[HN Gopher] Top Digital Calipers for Machinists (2021)
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Top Digital Calipers for Machinists (2021)
Author : walterbell
Score : 19 points
Date : 2022-06-20 07:51 UTC (15 hours ago)
(HTM) web link (www.practicalmachinist.com)
(TXT) w3m dump (www.practicalmachinist.com)
| Ancapistani wrote:
| I'd argue that most cheap calipers are fine - if you need the
| precision of a Mitutoyo, you should be using a micrometer anyhow.
| serf wrote:
| don't buy Mitu's on Amazon (the website links amazon referrals)
|
| they're famously counterfeited.
| mikewarot wrote:
| Most digital calipers use a capacitive stripe to measure
| distances, which consist of 0.1" grounded stripes on 0.2"
| centers. Using the same principle as a Vernier caliper, this gets
| interpolated into resolution down to quite small distances, even
| in the cheapest harbor freight model. Metric/Imperial scales are
| done in software.
|
| You can use a vinyl cutter to make a pattern in the same
| dimensions, and stick it on a conductive back, and make an
| arbitrary sized caliper, subject to the accuracy of the pattern
| once applied. You could also just machine it with a 0.1" end
| mill.
| tvb12 wrote:
| I'm under the impression that digital calipers are kind of like
| tape measures: the cheap ones measure as accurately as the
| expensive ones. I was told that expensive calipers have better
| circuitry and don't burn through the batteries when they're
| "off".
|
| Is that not the case?
| abakker wrote:
| 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.
| analog31 wrote:
| 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.
| tgsovlerkhgsel wrote:
| 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.
| mturmon wrote:
| 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).
| Blackthorn wrote:
| 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.
| varjag wrote:
| 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.
| phkahler wrote:
| When I got a 3d printer the very next thing was a digital
| caliper. Just a cheap $10 to $20 is fine since FDM print
| resolution is much less accurate. They are a required tool. My
| next tool will be a profile gauge.
| bityard wrote:
| When it comes to basically all measurement tools that a hobbyist
| would need, the top three companies are Starrett, Brown & Sharpe,
| and Mitutoyo. If you're just starting out or are limited in
| funds, buy these used from eBay or estate sales. If you need it
| to last for one project, go to Harbor Freight and buy two (in
| case the first one is DOA).
|
| Personally, I like dial calipers because they are just as
| accurate, don't need batteries, and can sometimes tell you things
| that a digital one can't.
| Blackthorn wrote:
| 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.
| msds wrote:
| Kinda a weird list; in my experience with hanging around lots of
| shops, it goes Mitutoyo 500-196-30 (non-IP67), Mitutoyo
| 500-752-20 (IP67), followed by a long tail of everything else.
| etrautmann wrote:
| yep, exactly my experience. I've almost never seen non Mitutoyo
| calipers anywhere that's not a personal/hobby shop
| mc32 wrote:
| Yes by and large, but the Starretts are no chopped liver.
| olivermarks wrote:
| Biggest problem I have with digital calipers, torque wrenches,
| micrometers etc is calibration. you only have to whack or drop
| them once before you no longer trust them and getting them
| checked isn't cheap
| brk wrote:
| 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.
| swighton wrote:
| 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.
| akgoel wrote:
| 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.
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