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Products => Other Equipment & Products => Topic started by: tooki on July 17, 2018, 10:20:46 am

Title: Digital calipers — what to buy?
Post by: tooki on July 17, 2018, 10:20:46 am
So I feel I’ve outgrown my $15 Aldi calipers. Actually, they’re junk: use more than a battery per year since they never truly turn off, but above all, depending on how you hold it, they often skip, so returning to zero suddenly the number has gone up in  2.54mm/0.1” steps, usually 5.08mm. I’ve fucked up countless measurements because of this. It’s easy to notice an added 5mm when measuring something that’s just 3mm, but on a 50mm object it’s not obvious. As the battery drains, it gets more and more sensitive to spurious jumps.

So it’s time for something proper. The local tool distributors carry a number of brands, and the ones I’ve been looking at are Mitutoyo (duh), Sylvac (Swiss) And Mahr (German). In fact one distributor has a sale right now covering a few models from each. (US brands are less likely to be available here.)

So what do I need to look for? I know I want the thumbwheel (any reason why I wouldn’t want it?), and ideally bigger digits. I also know the standard 6”/150mm is more than enough for me at the moment. I also don’t see any need for a data link. But what else should I look for? I assume IP67 rating keeps dust out and theoretically improves longevity, right? What about jaw shape? Micrometer resolution? Square vs round depth gauge? Carbide jaws? (Expensive!)

[Edit: since it doesn’t seem to be clear, I’m expressly asking for help evaluating which of those features make sense, because the range of models is overwhelming.]

Some models list “inductive” sensing. Others “absolute positioning”. What should I look for?

For what it’s worth, I was using a mitutoyo recently and, just like the instructor warned me, it was hella easy to accidentally hit the hold button and thus inadvertently not take a new reading at all. Didn’t like that button layout.

They’ve also got some sets on sale, with a caliper, micrometer, and various metalworking tools. I don’t think I need a micrometer, but is it worth having?

My actual needs are modest. I’m measuring mostly things like screws, components, cutouts, etc. But I absolutely hate using shitty tools, I want something dependable and that feels good in my hand, where the parts slide smoothly without wobble, with great usability.

So, any advice? Unfortunately, I don’t think there’s any opportunity to try before buying, nor any real return period, so I hope the hive mind can help me out! :)

Thanks in advance!
Title: Re: Digital calipers — what to buy?
Post by: TERRA Operative on July 17, 2018, 10:54:37 am
Anything with the brand name 'Mitutoyo' is worth the money and won't let you down.

I have been using my IP68 rated 'Absolute' series Mitutoyo calipers for 10 years and they still work fantastic.


https://ecatalog.mitutoyo.com/Calipers-C1331.aspx
Title: Re: Digital calipers — what to buy?
Post by: Muttley Snickers on July 17, 2018, 10:59:33 am
There are already a few existing threads on the forum which contain some very good information and recommendations all of which is still relevant, sorry I can't post links from this device.
Title: Re: Digital calipers — what to buy?
Post by: Andy Watson on July 17, 2018, 11:05:37 am
If your budget is adequate, another vote for Mitutoyo, but make sure they're genuine. Otherwise go for a brand name that is associated with metrology- this should increase the likelyhood that some quality control has been attempted.

I've been happy with these:
https://www.machine-dro.co.uk/150mm-6-digitronic-digital-caliper-moore-wright-basic-line-110-dbl-series.html (https://www.machine-dro.co.uk/150mm-6-digitronic-digital-caliper-moore-wright-basic-line-110-dbl-series.html)
Typically the battery is lasting about 18 months.
Title: Re: Digital calipers — what to buy?
Post by: wraper on July 17, 2018, 11:13:08 am
If your budget is adequate, another vote for Mitutoyo, but make sure they're genuine.
Yep, ebay is full of counterfeits
Title: Re: Digital calipers — what to buy?
Post by: tooki on July 17, 2018, 11:29:31 am
There are already a few existing threads on the forum which contain some very good information and recommendations all of which is still relevant, sorry I can't post links from this device.
Really? I did a search and didn't find any useful threads about calipers. (Mostly about cheap chinesium ones.)

If your budget is adequate, another vote for Mitutoyo, but make sure they're genuine.
Yep, ebay is full of counterfeits
As I stated in my OP, I'm looking at local tool distributors. Not ebay. So yeah, my budget can handle a Mitutoyo since I said that's what I was looking at! ;)



But yeah, folks, I know Mitutoyo is a safe bet, but they make a gazillion different kinds, and in my post I asked about features and usability. Any input on those?!? And what about the Swiss and German products? (They're priced pretty much the same as Mitutoyo.)
Title: Re: Digital calipers — what to buy?
Post by: Skashkash on July 17, 2018, 11:45:17 am
I have some mitutoyo calipers. And they are very nice. Also pricey.


The calipers I use all day long are. iGaging ABSOLUTE Origin.

 https://www.amazon.com/iGaging-ABSOLUTE-Digital-Electronic-Caliper/dp/B00INL0BTS (https://www.amazon.com/iGaging-ABSOLUTE-Digital-Electronic-Caliper/dp/B00INL0BTS)


They are better quality then the typical Chinese garbage, but what l like most about them is that they use a cr2032 battery that lasts forever. The absolute measurement feature is also handy for me.
Title: Re: Digital calipers — what to buy?
Post by: BradC on July 17, 2018, 11:51:22 am
Excepting that your Aldi calipers probably *are* crap, I've found a massive difference with battery life using genuine silver oxide cells rather than the LR44 alkalines even on my budget calipers & micrometers.
Title: Re: Digital calipers — what to buy?
Post by: HighVoltage on July 17, 2018, 12:19:35 pm
I have lots of Mitutoyu calipers and like them a lot, but ...

... my absolute favorite caliper is made by MAHR in Germany
This is the model 16 EWRi
It connects via wireless USB adapter to the PC and adds the measurements nicely to Excel.
The numbers are huge and is very well built.
It is a pleasure to work with this caliper.
And of course, it is switchable in the units.
Title: Re: Digital calipers — what to buy?
Post by: jpanhalt on July 17, 2018, 12:25:11 pm
I have Helios, Mitutoyo, Starrett, and Fowler measuring tools.  They are all at least 10 years old.   The Helios is from the mid-1970's and although it is a dial caliper, it still works great.  Just did a brief search and apparently Helios has been merged (?) with Fowler and/or another brand.   I would certainly give it a look.  Similarly, my Fowler instruments are older and very high quality.   Not sure about current products.   My Mitutoyo's are more recent (if 10 to 25 years qualifies) and have performed well.   

One thing to be aware of is the digital interface.   Mitutoyo is a modified SPI, and it has different versions.  That is no problem once you realize it and have the proper protocol, but finding documentation was a little more difficult. (I was using that device as a threading stop.)  My "goto" caliper is a Mitutoyo.  Never had a problem with hitting the wrong button, and if you do, it is easy to fix.
Title: Re: Digital calipers — what to buy?
Post by: eKretz on July 17, 2018, 04:20:49 pm
I am a former machinist, and am very picky about my tools. I probably own ten sets of calipers in varying sizes and different brands, and have used probably all the different brands over the years when borrowing or checking out coworkers' tools. My favorite digital calipers are Mitutoyo, hands down. Do listen to the above about watching for counterfeits if you buy from anywhere other than a reliable/reputable tool vendor.
Title: Re: Digital calipers — what to buy?
Post by: ataradov on July 17, 2018, 04:26:33 pm
The calipers I use all day long are. iGaging ABSOLUTE Origin.
I double that. iGaging makes excellent tools at very reasonable prices.
Title: Re: Digital calipers — what to buy?
Post by: eliocor on July 17, 2018, 04:40:59 pm
Mitutoyo, but the real ones (beware of the imitations!).
I own also some micrometers from the same company: excellent ones!

The only drawback is the battery consumption: when not in use for long time I remove the battery from the micrometers.
Title: Re: Digital calipers — what to buy?
Post by: tpowell1830 on July 17, 2018, 04:45:42 pm
I am a former machinist, and am very picky about my tools. I probably own ten sets of calipers in varying sizes and different brands, and have used probably all the different brands over the years when borrowing or checking out coworkers' tools. My favorite digital calipers are Mitutoyo, hands down. Do listen to the above about watching for counterfeits if you buy from anywhere other than a reliable/reputable tool vendor.

Same here, former machinist, Mitutoyo is tops. Also, FWIW, I would also get the dial caliper version of same so that when your battery dies, you can still measure.

Just my 2 cents...
Title: Re: Digital calipers — what to buy?
Post by: Pinkus on July 17, 2018, 05:02:54 pm
after being annoyed for years about the 15 Euro digital calipers, I finally purchased a Tesa caliper with a round scale half a year ago as a test (I got a really good one, almost unused, for 20 Euro on Ebay, new: at least 100 Euro).
My eyes are not good enough anymore for a regular mechanical caliper, so I thought I give a decent dial caliper a chance. Well ...... I haven't used the digital ones since.
Thus take this as a hint to look at this kind of caliper too.

Btw, as you are Swiss: Tesa is Swiss made! You can find them used on Ebay..... just be patient until you find a decent one (and check, that you get a version where you can rotate the scale to zero).
Title: Re: Digital calipers — what to buy?
Post by: eKretz on July 17, 2018, 05:48:34 pm
Yep, Tesa is another very good brand. Older Brown and Sharpe dial calipers are among the best I've ever used - IIRC I read somewhere that they were made by Tesa for Brown and Sharpe. I've got a large selection of those available also.

For any of you guys new to precision measuring - other than which ones are good brands, the next thing you need to know about calipers is DON'T SQUEEZE when measuring. Calipers are meant to TOUCH the surface being measured, not clamp it! If you apply pressure when measuring you are destined to make very inaccurate measurements. Any pressure more than just enough to make good contact will flex the caliper and cause measurement error, so it's important to align the tool well to the surface being measured.
Title: Re: Digital calipers — what to buy?
Post by: tooki on July 17, 2018, 06:06:31 pm
Thanks for the replies so far. But does anyone here have any thoughts on the features and usability questions? I’m not just asking for brand suggestions. I have a list of specifics in the post.
Title: Re: Digital calipers — what to buy?
Post by: tooki on July 17, 2018, 06:08:15 pm
I have lots of Mitutoyu calipers and like them a lot, but ...

... my absolute favorite caliper is made by MAHR in Germany
This is the model 16 EWRi
It connects via wireless USB adapter to the PC and adds the measurements nicely to Excel.
The numbers are huge and is very well built.
It is a pleasure to work with this caliper.
And of course, it is switchable in the units.
What about the Mahr makes you prefer them over the Mitutoyo?

Nice to know the data link works, but I wasn’t planning on getting one with a link, I don’t need it! :)
Title: Re: Digital calipers — what to buy?
Post by: ataradov on July 17, 2018, 06:09:53 pm
Thanks for the replies so far. But does anyone here have any thoughts on the features and usability questions? I’m not just asking for brand suggestions. I have a list of specifics in the post.
With good digital calipers you are pretty much locked into a very specific feature set. So you get what you get.
Title: Re: Digital calipers — what to buy?
Post by: tooki on July 17, 2018, 06:17:57 pm
Thanks for the replies so far. But does anyone here have any thoughts on the features and usability questions? I’m not just asking for brand suggestions. I have a list of specifics in the post.
With good digital calipers you are pretty much locked into a very specific feature set. So you get what you get.
:-DD Dude I created my list of questions based on the plethora of models stocked just at one tool vendor! Did you even look at the list?!
Title: Re: Digital calipers — what to buy?
Post by: cheeseit on July 17, 2018, 07:29:44 pm
No real experience with much else or any kind of expert so for what it's worth..

Have had a digital Mahr for nearly 20 years that is rock solid and has never let me down. Only problem is that it chews through the battery too fast, but that is to be expected for its age I think.

Would like a thumb wheel but it's not critical (to me) since it moves smoothly. No big digits; I don't care. Has serial data link but never used it. No idea about IP67 but never had a problem, I just wipe it down every few years or so, and it's always in the open on my desk. Never had the cover for data link so pretty much open for dust ingress too. Square depth gauge works fine. Super tough steel and jaws are as sharp as new, despite having been used for lots of poking and as a scribe; I wish all my probes were as sharp. Uses absolute positioning. Goes from end to end (153.63 mm) reliably, with zero or 0.01 mm deviation. No hold button but a locking screw that does not change the reading. Buttons are spring loaded and does not accidentally get pressed.

I suspect that it'll last me at least another 20 years, or until the LCD dies, which btw. is still as new. If only all my tools were of this quality..
Title: Re: Digital calipers — what to buy?
Post by: blueskull on July 17, 2018, 07:54:53 pm
I have a 500-196-30, and I'm happy with it. It's an absolute origin model, so there's no skipping even when you move it fast. For around $125, it's not a bad deal.
For your "modest" use case, this model is more than enough. I use it to measure chip size, chips height, CNC parts, enclosures and basically every small thing that I tinker with.
Being a simple model, it has little points to fail, and it survives a lot of abusing (being tossed in tool bag, not being cleaned for more than a year, forgot to turn off, etc.). Of course, I'm not prying with it.
Its battery lasts relatively long. I got mine for at least 2 years, and it is still strong on its original battery. It's not a CR2032, but it lasts long enough not to annoy me.
Title: Re: Digital calipers — what to buy?
Post by: metrologist on July 17, 2018, 07:55:40 pm
Thanks for the replies so far. But does anyone here have any thoughts on the features and usability questions? I’m not just asking for brand suggestions. I have a list of specifics in the post.
With good digital calipers you are pretty much locked into a very specific feature set. So you get what you get.
:-DD Dude I created my list of questions based on the plethora of models stocked just at one tool vendor! Did you even look at the list?!

Most of the answers will be, it depends...

I want the thumbwheel: mee too
ideally bigger digits. Good to have, yes mee too

I also know the standard 6”/150mm is more than enough for me at the moment. I also don’t see any need for a data link. But what else should I look for? Look for the realization that a caliper is not a precision measuring tool. there is a calibration video I'll try looking for...

I assume IP67 rating keeps dust out and theoretically improves longevity, right? yes, in theory

What about jaw shape? I like the standard jaw shape, unless you have a specific application that needs something else. All my caliper jaws are nearly the same. I do have use for various anvils and such on my micrometers (this is foreshadowing).

Micrometer resolution? 5 or 2 tenths is enough

Square vs round depth gauge? I like a blade depth guage, but have depth guage micrometers. A round guage will get into smaller areas than a blade, but could flex. I'd like ones of each.

Carbide jaws? (Expensive!) This is a must for your primary. I have toss-arounds that are plain steel, but I like to mark my parts with the calipers and that is why carbide is important. That will make them last longer.

Some models list “inductive” sensing. the other is "capacitive". Not sure which is better, but I've read more about capacitive.

Others “absolute positioning”. depends. you know what it means. Nice if it can be set one way or the other. None of mine are absolute, except the dial calipers.

I don’t think I need a micrometer, but is it worth having? only if you want to make precision measurements. calipers are really only good to the thou as they are flexible enough that it depends on how you use it one day to the next.

Even the cheap mics are very accurate now. Get a tenths reading mic set and a moderately decent caliper. If you want to spend a lot, I would love to have that Mahr shown above; otherwise, I like my old dial Brown & Sharpe and Mits. I also have a decent SPI with carbide jaws.
Title: Re: Digital calipers — what to buy?
Post by: David Hess on July 17, 2018, 08:05:25 pm
My favorite calipers are my Mitutoyo vernier ones because they are borrow proof and the batteries never need changing.

If I was going to buy some new low cost ones, I might try General Tools (https://www.generaltools.com/hand-tools/precision-measuring-marking/calipers-micrometers?limit=all).  I like the quality of their other products.
Title: Re: Digital calipers — what to buy?
Post by: rhb on July 17, 2018, 09:05:22 pm
Calipers are good to a few thousandths.  Calculate how much they expand when they warm up a few degrees while held in your hand.

I have several of the cheap Chinese digital calipers, but the battery life is terrible if you don't remove the battery after use or install a switch.  As a consequence I've switched back to using my dial calipers almost all the time.  I use one of my Chinese dial calipers for something every day.

Also if you want to set to a particular distance, dial calipers are much easier to adjust.

I bought a set of gauge blocks and checked my dial calipers and they were in spec.  Most of mine came from ENCO which no longer exists,  but the going price for the Chinese 6" is $20 and for a top tier $120-150.  If you *ever* drop one it is ruined.  If you need a measurement to less than 0.005" you need a micrometer (and a thermometer in many cases).

The situation where digital really shines is statistical process control where the data are recorded automatically by a computer.  Also they deal with grinding machine coolant better as there is no rack and pinion for the abrasive coolant to damage.  You're also unlikely to misread a digital caliper which is a minor plus.
Title: Re: Digital calipers — what to buy?
Post by: sn4k3 on July 17, 2018, 09:24:17 pm
I own some cheap digital calipers from china, and they are bad. Not much because resolution but more because it keep lossing power and if you go far it will display a crazy value at random, so they are trash.
What i find good and so far it has been excelent is this: https://www.aliexpress.com/item/Waterproof-IP54-Electronische-Digitale-Messschieber-Measuring-tool-0-01mm-5001-150-Free-Shipping/1284242843.html (https://www.aliexpress.com/item/Waterproof-IP54-Electronische-Digitale-Messschieber-Measuring-tool-0-01mm-5001-150-Free-Shipping/1284242843.html)

The battery size are better than the cheap ones, better resolution, no crazy jumps and you can log data with a USB cable to the PC. Since i have this i have 0 problems and very accurate values.
Worth the money
(Battery not included)

To larger sizes see: https://www.aliexpress.com/item/free-shipping-SHAHE-stainless-steel-0-150-mm-digital-caliper/32645456925.html (https://www.aliexpress.com/item/free-shipping-SHAHE-stainless-steel-0-150-mm-digital-caliper/32645456925.html)
Title: Re: Digital calipers — what to buy?
Post by: G0HZU on July 17, 2018, 10:41:21 pm
For many years I've been using these basic 150mm digital calipers and they are fairly cheap at about £36 from Farnell:

http://uk.farnell.com/linear-tools/49-923-150/digital-caliper-150mm-6/dp/1375863 (http://uk.farnell.com/linear-tools/49-923-150/digital-caliper-150mm-6/dp/1375863)

They are a bit heavy on batteries (SR44) but I find them to be reliable and easily good enough for my needs. I've also got a set of genuine Mitutoyo 532 (fine adj) 150mm calipers. However, I only use these when I'm out of batteries for the digital calipers.

Obviously, these £36 digital calipers can't compete with a decent/expensive set from Mitutoyo but they seem to be reliable and I don't see any skipping/slipping effects with them. I think the accuracy spec is +/-0.02mm below 100mm and this is reasonable but not spectacular.
Title: Re: Digital calipers — what to buy?
Post by: Dubbie on July 17, 2018, 10:56:43 pm
I've got mostly Mitutoyo gear in my shop. Micrometers, Calipers, Boregages, Height gages, Dial Indicators,  etc.

However I do have a couple of sets of measuremaX calipers that seem to perform as well as my Mitutoyo ones. They are about 1/2 price compared to the Mitutoyos
https://www.measumax.com/31-180 (https://www.measumax.com/31-180)

I have had some no-name Chinese ones in the past which have been rubbish. I think the lesson is, you get what you pay for.


Title: Re: Digital calipers — what to buy?
Post by: mmagin on July 17, 2018, 11:47:56 pm
I bought one of the usual 6" Mitutoyos used on eBay a couple years back (very scuffed up case, but the instrument was just fine) and it's so much nicer than all the cheap calipers.  Also, the battery life is amazing.
Title: Re: Digital calipers — what to buy?
Post by: vltr on July 18, 2018, 01:04:57 am

So it’s time for something proper. The local tool distributors carry a number of brands, and the ones I’ve been looking at are Mitutoyo (duh), Sylvac (Swiss) And Mahr (German). In fact one distributor has a sale right now covering a few models from each. (US brands are less likely to be available here.)

So what do I need to look for?
Since it seems you are most interested in feel and general quality I would recommend Japanese made mitutoyos.(Yes it does make a difference.  I have a pair of 1cm dial indicators one made in japan the other in us.  Same design same part number and the smoothness of movement, solidness, and general build quality are all much higher on the japanese made one).  I also have a brazilian made mitutoyo dial caliper I use every day at work, and I can say it again suffers from being not quite as nice as the japanese models though still miles ahead of cheap chinese models


Quote
I know I want the thumbwheel (any reason why I wouldn’t want it?),
I find a thumbwheel easier to use when trying to move the calipers a short distance or back and forth over a measurement.  My 12" calipers do not have a thumbwheel and I find it much better when I'm sliding a long distance, but trying to get right to final measurement is a little more finicky.
Quote
and ideally bigger digits. I also know the standard 6”/150mm is more than enough for me at the moment.
If you can I would recommend an 8".  It can be surprising how often just a little more measurement space will help, and they're not nearly as big and ungainly as a 12"
Quote
I also don’t see any need for a data link. But what else should I look for? I assume IP67 rating keeps dust out and theoretically improves longevity, right?
IP67 is waterproof for keeping coolant from machining out.  For regular use this isn't really needed
Quote
What about jaw shape?
Unless you know you need something funky go with the standard common jaws
Quote
Micrometer resolution?
I don't trust a caliper to tighter than .002/.003" really so I wouldn't spend extra on anything tighter than the commonly available half thou readout.
Quote
Square vs round depth gauge?
round fits in more spaces but is more easily damaged.
Quote
Carbide jaws? (Expensive!)
Really nice for high precision kind of a waste on calipers imo.
Quote


[Edit: since it doesn’t seem to be clear, I’m expressly asking for help evaluating which of those features make sense, because the range of models is overwhelming.]

Some models list “inductive” sensing. Others “absolute positioning”. What should I look for?
absolute is less prone to the jumps that have been bugging you, but on any higher end caliper this really should not be a problem.
Quote

For what it’s worth, I was using a mitutoyo recently and, just like the instructor warned me, it was hella easy to accidentally hit the hold button and thus inadvertently not take a new reading at all. Didn’t like that button layout.

They’ve also got some sets on sale, with a caliper, micrometer, and various metalworking tools. I don’t think I need a micrometer, but is it worth having?
If you don't need to measure something solid to a tolerance of less than .002/.003" micrometers aren't really going to do anything for you, especially since you will need several just to cover a small range. 
Quote

My actual needs are modest. I’m measuring mostly things like screws, components, cutouts, etc. But I absolutely hate using shitty tools, I want something dependable and that feels good in my hand, where the parts slide smoothly without wobble, with great usability.

So, any advice? Unfortunately, I don’t think there’s any opportunity to try before buying, nor any real return period, so I hope the hive mind can help me out! :)

Thanks in advance!


I think I answered as many of your questions as I could.  I'm not an expert by any means, I'm just a machinist who uses these tools every day so I have some opinions.  My general advise would be to make sure you want a digital caliper over something like a dial caliper.  I personally find the dial caliper easy to trust since I don't have to worry about batteries, or if I pressed the wrong button or anything else.  Obviously some people will really prefer the general ease of use reading a digital caliper so that's up to you. 

Based on what you've posted for your needs I wouldn't waste money on fancy features since pretty much any "name brand" is going to have the general feature set to make you happy.  Most of my measurement tools are older American or newer Japanese so I can't comment on European manufactured items too much.  I do have a couple swiss made dial indicators and I have found them high quality and smooth operating, but they always feel more fragile to me so I wouldn't recommend them as a main tool to be used and abused every day, but they are the ones I bring out when a measurement just HAS to be right. 
Title: Re: Digital calipers — what to buy?
Post by: eKretz on July 18, 2018, 03:07:51 am
Ok, more specifically: the thumbwheel is nice for fine adjustment,  but also makes it VERY easy to apply too much pressure.  I do like them on smaller calipers for sure.  Jaw shape is kind of a non-issue unless you're measuring into tiny grooves, and even then much of the time. Tungsten carbide jaws are great,  but not necessary for someone who's not measuring steel every day all day. For someone not doing production work like that the hardened steel jaws will last indefinitely. Please do not use your calipers as a scribing tool, that is definitely not what they're intended for. Even the guys who do this will admit it eats the jaws up. Also avoid trying to measure sharp edges like on hardened cutting tools unless you use caution. Round vs. square depth rod has never really mattered to me. I have had calipers with both and there's not much difference except that the round rod can occasionally get into places (again,  some small grooves) the square one can't.  My personal preference is for the square/ rectangular rods - the round ones always seem to warp more often.

Calipers aren't meant to be precision measuring tools. They will get you close,  but they're not micrometers. If you're careful and you know what you're doing,  you'll get within .001" - .002" - sometimes closer.  The temperature change and resultant expansion when you hold the bar in your hand hurts caliper accuracy,  and so does the necessary slop to let them slide freely. Any additional pressure hurts it even more.
Title: Re: Digital calipers — what to buy?
Post by: KE5FX on July 18, 2018, 03:29:04 am
Look for a (genuine) Mitutoyo CD-8.  It addresses basically everything on your list... awesome quality, perfect ergonomics, plenty of length (8"/200mm), recessed zero and origin buttons, nice large digits.

It has an ON/OFF switch, but I never use it.  I leave it on all the time, and I still get 2+ years of battery life.  If I were to turn it off, I imagine the battery's service life would basically be equal to its shelf life.
Title: Re: Digital calipers — what to buy?
Post by: KL27x on July 18, 2018, 03:36:56 am
If your calipers are skipping 0.1" here and there, it's possible your calipers are dirty. Doesn't matter if they're Mitutoyo or $10.00 calipers. Grease or dirt can skew the reading by changing the capacitance. Bad enough, and maybe the micro gets confused. The other potential issue is slow wakeup. If they are the kind that turn on automatically when you move them, maybe you are just moving them too fast from sleep. I always check they're zeroed after turning them on, anyway.

I use the silver oxide batteries in my cheap calipers. I use them all the time. I probably change them no more than once a year. Maybe every other year?

The main issues I have had with the cheap stuff are minor quibbles for my own needs. The battery case might be a little shiite, so that the meter turns on/off by itself. This is a pretty easy fix. Roughness in the movement is another thing you sometimes get. But I have 2 calipers that cost about $10.00 which are smooth as anything and very solid. Never had any problem like you had with your Aldi, except that they can get flaky when the battery is dying. Just had to futz with the cover on the one, and I dropped and broke the glass on one; still works great. It's a bit of a gamble, but if I bought 4 cheapo pairs from 4 different vendors, I'd probably have at least one excellent pair of calipers and 4 perfectly usable tools. 

I keep a caliper at the electronics bench, and 3 more in the garage in spots where I use them. By the sander and routing table, next to the shooting board, etc. I'd rather the cheap one where I use it than one "good" caliper in a padded case.

Come to think of it, the erroneous reading thing was a small but real, nagging fear before I switched to the silver oxide LR44. Aside from simply lasting much, much longer, I think the silver oxide produce a more flat voltage and don't screw with the microcontroller so much at their end.  These should be standard fare for calipers.
Title: Re: Digital calipers — what to buy?
Post by: CatalinaWOW on July 18, 2018, 05:01:34 am
Another vote for dial calipers.  Easy to read, infinite battery life.  If you aren't logging your measurements there is little advantage to the digital units.  I have several digitals, which rarely get used while the dial calipers are used daily. 

Features - I agree on thumbwheel, and locking set screw.  These are almost universal so not really a selection feature, except to reject a few outliers.  If you need precise hole diameters a head designed for that helps, but the standard head shape is better for most uses.  If you are doing that much hole work you probably need to invest in another set and then use the appropriate one for each thing. 

For electronics uses I haven't ever seen anything which would drive a preference on depth gauge configuration.  The 150 mm/ 6 in size meets most needs and is convenient to handle and store, but there is always something that wants a bigger range.  Unfortunately prices really rise and the larger sizes are unhandy for smaller jobs.
Title: Re: Digital calipers — what to buy?
Post by: JonM on July 19, 2018, 04:36:35 am
My primary calipers are Mitutoyo but I also have several SPI "Swiss Made Plastic Dial" calipers which are lightweight, and non-conductive which can often be useful.

I have not yet changed the batteries in the Mitutoyo after several years, even after putting it away with the power on several times. I have some Harbor Freight digital calipers that burn through batteries while sitting unused.

 
Title: Re: Digital calipers — what to buy?
Post by: Fsck on July 19, 2018, 04:45:25 am
I use dial calipers because I keep forgetting to get new batteries for the digital ones.
I use some old Fowler NSK made in Japan ones I got off kijiji (canadian craigslist, etc)
Title: Re: Digital calipers — what to buy?
Post by: KL27x on July 19, 2018, 09:58:54 am
It's ironic that electrical engineering types can't be bothered with batteries. It's a given that I have CR2032 and silver oxide LR44 (and probably 12 other kinds of batteries) in a box at my electronics bench.
Title: Re: Digital calipers — what to buy?
Post by: David Hess on July 19, 2018, 10:11:45 am
I think it is more of a problem that battery life is so short with other than the best calipers.  After you get through Mitutoyo's web site, you can find their operating life specifications in *years*.
Title: Re: Digital calipers — what to buy?
Post by: KL27x on July 19, 2018, 11:32:23 am
1-2 years seems pretty reasonable to me. This is what I get with the silver oxide batteries. (6 months maybe on alkaline.)

I've a depth gauge (same old thing as regular digital calipers, really, just a different shape) that takes CR2032. I'll be curious to see how long it lasts.

My pen DMM probably eats a CR2032 per year. Small price to pay for the ergos.

Smoke detectors? Watches? Yeah, I don't like changing batteries in those, for some reason. But I don't think I'd buy $100.00 smoke detectors that last 3x as long per 9V. But, meh. Maybe if it were made in Germany or Japan it would be worth it. :)

Now I'm curious. For $100.00, do Mitutoyo calipers ship with an alkaline battery or a silver oxide? The difference is enormous. There's a crapton of energy left in an alkaline by the time a single cell can no longer power a micro. It's a curious design choice. There are dozens of 3V button cells that are smaller and would last several times longer.
 
Title: Re: Digital calipers — what to buy?
Post by: eKretz on July 19, 2018, 06:09:36 pm
If you get a good pair of digital calipers and don't use them all day every day, battery life is NOT even relevant. I have a set of Mitutoyo calipers that I use all the time that have been on the same battery for nearly 7! years. I will change the battery soon, the display is starting to get dim. Mitutoyo is absolutely the best on battery life that I have used.
Title: Re: Digital calipers — what to buy?
Post by: HighVoltage on July 19, 2018, 06:23:27 pm
Mitutoyo is absolutely the best on battery life that I have used.
They are the best, when it comes to battery life!

It really does not matter much, if you leave a Mitutoyo ON of OFF, the battery will last about the same.
The ON/OFF switch is just for "feel good".



Title: Re: Digital calipers — what to buy?
Post by: bitwelder on July 19, 2018, 07:00:54 pm

The calipers I use all day long are. iGaging ABSOLUTE Origin.

 https://www.amazon.com/iGaging-ABSOLUTE-Digital-Electronic-Caliper/dp/B00INL0BTS (https://www.amazon.com/iGaging-ABSOLUTE-Digital-Electronic-Caliper/dp/B00INL0BTS)


One more vote for the iGaging. For me they are a good middle-ground between the top class Mitutoyo and the crappy Chinese clones.
Title: Re: Digital calipers — what to buy?
Post by: KL27x on July 19, 2018, 07:32:17 pm
Quote
It really does not matter much, if you leave a Mitutoyo ON of OFF, the battery will last about the same.
This has been stated at least 3 times.
No one uses the off button, on any calipers, do they?

And yes, it does make a difference, technically. But for most users, the calipers will spend 1000x more time in sleep than actually on. The improvement in battery life between a Mitutoyo and a cheap chinese calipers is mostly due to lower sleep current. This has been measured and demonstrated. I don't recall the actual figures, but it is several fold difference in sleep current draw. This is not remarkable. If you compare sleep current between different micros, you can find many fold differences.

There is a new wave of large digit cheap chinese calipers. I wonder if they use the same micro. I avoided buying them because for a lot of small things I think in thou, and the big digit displays have the big digits only down to hundredths and a small digit for the thou and the half... irritating.

I would bet $2,000 that iGaging uses the exact same pcb's, circuitry, and micro as any $10.00 caliper. They might have better quality control as far as the polish and fit on the steel bits.

As far as accuracy of a digital caliper, it comes down to the accuracy of a printed circuit board glued onto a bar of steel. Even if mit's are higher in quality control, that means maybe 90% of cheap calipers would be exactly as accurate. It would be important for (some) professional machinists the way a calibrated 6 digit meter is important to (some) electrical engineers. For me, if it matters, there's the mitty. If it doesn't, there's not much purpose of the "middle ground" (re)brands. If you don't have a mill or metal lathe and regularly use a set of pin gauges and 1-2-3 blocks, you will never realize a difference. Even if you're a pro machinist, the main benefit for you is that when you do inevitably mess up your job (for unrelated reasons), no one is going to see you standing there holding a pair of $10.00 calipers. A machinist need mittys for the same reason a mechanic needs a steel tool chest covered in stickers and a lawyer needs to wear a suit in court. Or an EE needs a JBC or Metcal. :)

The fact that the battery life is a major selling point is weird to me. A smoke detector that lasts 30 years would improve my life way more than Mitty calipers. But no one is going to rave about a smoke detector and not many would pay 10x as much for one. 

Keep in mind... silver oxide LR44. If you're not using it, you're doing it wrong.
Title: Re: Digital calipers — what to buy?
Post by: KE5FX on July 19, 2018, 10:17:18 pm
As far as accuracy of a digital caliper, it comes down to the accuracy of a printed circuit board glued onto a bar of steel. Even if mit's are higher in quality control, that means maybe 90% of cheap calipers would be exactly as accurate. It would be important for (some) professional machinists the way a calibrated 6 digit meter is important to (some) electrical engineers. For me, if it matters, there's the mitty. If it doesn't, there's not much purpose of the "middle ground" (re)brands. If you don't have a mill or metal lathe and regularly use a set of pin gauges and 1-2-3 blocks, you will never realize a difference. Even if you're a pro machinist, the main benefit for you is that when you do inevitably mess up your job (for unrelated reasons), no one is going to see you standing there holding a pair of $10.00 calipers. A machinist need mittys for the same reason a mechanic needs a steel tool chest covered in stickers and a lawyer needs to wear a suit in court. Or an EE needs a JBC or Metcal. :)  The fact that the battery life is a major selling point is weird to me. A smoke detector that lasts 30 years would improve my life way more than Mitty calipers. But no one is going to rave about a smoke detector and not many would pay 10x as much for one.  Keep in mind... silver oxide LR44. If you're not using it, you're doing it wrong.

Actually I use every bit of the precision and accuracy I get from the Mitutoyo, and could even stand more.  Measuring the core thickness on a 6-layer board under a microscope is a job for more specialized tools, but lacking those, the calipers had better be good.

It's also used frequently to identify features that show up in a high-resolution TDR plot.  The quality isn't as critical there but the 8" length comes in handy.  And of course I benefit from the battery life every time I use it without having to replace the battery first.

Definitely a good idea to keep a good pair and a crappy pair around, so you're not tempted to use one where the other is called for.
Title: Re: Digital calipers — what to buy?
Post by: KL27x on July 19, 2018, 10:26:41 pm
Quote
Measuring the core thickness on a 6-layer board under a microscope is a job for more specialized tools, but lacking those, the calipers had better be good.
I hate to be that guy, but the cheap calipers are going to give you the same reading as your Mitutoyo on that small of a measurement. Down to maybe one blinks the half thou or not. If you could remove all human error and material compression/surface finish error, you would have that same issue between 2 pairs of Mitts, given the thing being measured might fall right on the fence.

Quote
It's also used frequently to identify features that show up in a high-resolution TDR plot.  The quality isn't as critical there but the 8" length comes in handy.
this is where you might see a significant (and repeatable) difference, at the long end of the scale. Due to cumulative pcb printing error and/or pcb warpage. This is where Mitt will actually ( I bet) test and discard in QA. But this is where you say the precision isn't as critical. So a cheap caliper might have 1 mil offset per inch you go. 

Quote
And of course I benefit from the battery life every time I use it without having to replace the battery first.
Yes, this is undeniably true. You got that one right.
Title: Re: Digital calipers — what to buy?
Post by: KE5FX on July 19, 2018, 10:55:13 pm
Quote
Measuring the core thickness on a 6-layer board under a microscope is a job for more specialized tools, but lacking those, the calipers had better be good.
I hate to be that guy, but the cheap calipers are going to give you the same reading as your Mitutoyo on that small of a measurement. Down to maybe one blinks the half thou or not. If you could remove all human error and material compression/surface finish error, you would have that same issue between 2 pairs of Mitts, given the thing being measured might fall right on the fence.

Sure.  And the next time I make the measurement, will I get the same number?  How about the time after that?  When I glance away from the microscope to view the caliper display, how much did the cheap mechanism move... whether I tightened the locking screw or not?

When verifying PCB layer thickness with calipers, you don't use compression.  If you apply any force at all, you'll never be able to make accurate, repeatable measurements.  Instead, you focus the scope on both the layer under inspection and the caliper jaws at the same time, opening the caliper carefully to produce a matching gap.  You're measuring distances very close to zero, and you need at least 10x the final precision of the measurement you're trying to make.  How often does a cheap pair of calipers produce a repeatable zero down to 10 micrometers, anyway? 
Title: Re: Digital calipers — what to buy?
Post by: KL27x on July 19, 2018, 10:58:49 pm
Quote
Sure.  And the next time I make the measurement, will I get the same number?
IME, yes. IMO, cheap calipers are more than likely just as repeatable as a Mitt. It's the absolute accuracy at longer distances where the Mitt is going to prove its worth. The way they measure is pretty much exactly the same and depends on the accuracy of the capacitative pads on a PCB, and last I checked Chinese PCB manufacturers know how to make pcb's.

The only time I can get a different reading is if there's grease on the caliper. Other than that, all my calipers are perfectly repeatable down to the last thou. Wipe the jaws off, wipe the bar off, zero, and hold the same way on a smooth, rigid object? Perfectly repeatable. 

I have used them to machine dies where precision must be within a thou. They work. Every time. First time I did this, I had to constantly measure my reference object for peace of mind. It is hard to believe how repeatable a $10.00 caliper is. It took time, but now I trust them implicitly to a thou... more accurate than you can even get unless you take the time to go through that little ritual of cleaning the calipers and all. If I order precision made part under an inch or so, I will either measure the exact number down to the last mil, or the supplier got it wrong.

If I measure 401 thou on a steel rod 9 times out of ten, and 401.5 one out of ten (due to surface irregularity), today, it will measure the same thing tomorrow and the day after and it will measure the same with all of my calipers.

If you need precision beyond a thou, a Mitt won't do that, either. If you're a machinist asked to make something 4" long to tolerance of a thous, then you want a Mit.
Title: Re: Digital calipers — what to buy?
Post by: eKretz on July 20, 2018, 12:32:22 am
No they aren't just as repeatable. The materials used, the finish on the ground steel, the tolerances hit or missed, the squareness and parallelism of the ground surfaces etc. etc.  These are all areas that hugely impact accuracy and repeatability. They are also excellent on a quality caliper and terrible on many of the cheap Asian imports. And yes, I HAVE measured and checked repeatability. Many of the cheap calipers also will move when locked, as well as change the jaw angle so that they are no longer parallel. They may also measure a different size if you check up near the bar vs down near the end of the jaws. The good calipers suffer none of these issues. The cheap brand do not worry so much about quality control and accuracy, as evidenced by many cheap junk products on offer. I have personally bought plenty of Chinese Junks and been disappointed by many. Every now and then you get something decent though.
Title: Re: Digital calipers — what to buy?
Post by: KL27x on July 20, 2018, 12:42:16 am
Quote
the squareness and parallelism of the ground surfaces etc. etc.
This is debatable if it even qualifies as repeatability. If you measure the same way on the same place on the jaws, this doesn't have an effect.

That said, I have not found any problem in this area with my calipers that makes a significant effect. Significant with respect to the resolution at hand. I have noticed no problem in 3 sets. Considering I drop them and use the tips to scribe stuff, I don't know that it would matter. And as far as parallelism or evenness of the jaws, I am fully capable of stoning a set of steel jaws if I needed to. When you need a measurement down to a thou, you can't expect to get an accurate reading by clamping down with significant force, anyway. Of course this will flex even a Mitutoyo.

One set of calipers I have has a unique solution to the fit between the sliding bars. It rides only one one side; there's a leaf/bar spring to keep the parts on the one direction to take out play/slack. This one was very rough in movement (pretty decent after some buffing). My other two sets don't have this feature (that I recall since looking inside), but they slide tight and buttery smooth. And we're talking 6" of interface, which is enormous. (Maybe opened beyond 4"+, the precision of mating will become significant).

We have different experience. All my calipers are repeatable. And as far as absolute accuracy*, I have purchased several precision dies and materials and they always measure exactly as advertised. I even have developed suspicion that when machinist makes a steel rod/shaft specified to a thousandth, that he always makes the MAX diameter to that spec. Probably to avoid complaints that it doesn't fit. The average reading I get in this particular type of case is typically half a thou low.

I believe some people have a bad experience. I'm 3 for 3; I think it's probably a pretty good gamble. Esp if you can read current reviews for the thing. On mine, not wiping off the jaws has more effect on reading than any issue you described. Maybe it would be faster or easier to use the Mitutoyo (incorrectly/sloppily) and get the right reading? Dunno. I have no need to find out, up to now. A 0.400" rod and a 0.401" are worlds apart for certain things I have done. And my $10.00 calipers easily discern the difference, repeatably, and unambiguously... both relatively and absolutely with no need to reference against a pin gauge. How much better can a half a thous resolution device get than that, I have to wonder.

*And why wouldn't they be abolutely accurate? There's just a repeating pattern on the pcb/slide. Then the measurement is relative to where you zero it.
Title: Re: Digital calipers — what to buy?
Post by: eKretz on July 20, 2018, 03:02:48 am
So you've been exposed to 3 sets of calipers? I've seen hundreds. Used to work at a place with 150 machinists. And the whole point of accuracy in construction of a caliper in terms of that squareness and parallelism is so that you don't have to measure in exactly the same place twice. I guarantee you're not doing that with your calipers in most cases. Unless you've got a scribed alignment line on the jaw that you're lining up with a microscope every time you make a measurement?

Regardless, this is mostly academic, as calipers just aren't that accurate to begin with. But why not do everything possible to make them as accurate as they can be? The cheap companies don't do that, and let all kinds of garbage through that would get bounced in a heartbeat at any reputable company - like coarsely ground surfaces that need to be stoned to smooth the sliding surfaces. And stoning the jaws will NOT correct geometry errors. That takes actual substantial metal removal, i.e. grinding. Your 3 pairs may be decent, but they produce hundreds of thousands of pairs, and I have seen plenty that are NOT up to snuff. When you buy cheap junk, what you get is basically a roll of the dice.

As far as your implication that I don't know how to use a measuring tool like a caliper as well as you do...I honestly have no words. How many machine shop have you worked in and for how many years?

Being that I actually made precision devices and machinery for a couple decades, I recognize poor craftsmanship when I see it. For things that I use while pursuing my livelihood, I want good quality tools that make my job easier, not those that I need to worry about. Personally I appreciate the good quality work that goes into better tools, and they are almost always far more pleasant to use. And for the relatively inconsequential difference in price for something like a caliper, IMO it's silly not to get something good. YMMV, and that's fine.
Title: Re: Digital calipers — what to buy?
Post by: KL27x on July 20, 2018, 03:26:43 am
Cheers, man. I'm not trying to be confrontational.

Quote
As far as your implication that I don't know how to use a measuring tool like a caliper as well as you do
I'm sorry that you have inferred something I did not intend to imply.

Quote
Regardless, this is mostly academic, as calipers just aren't that accurate to begin with.
This is what I believe, too. WTF. It's like we agree. I think the 3 $10.00 calipers I own are all good enough in the right places to give precise measurements down to their inherently limited resolution of half a thou. (Plus or minus maybe 1 thou per inch of absolute offset, probably starting to get weird at maybe 2" and getting some play and repeatability issues when you open the jaws much over halfway, limiting the bearing surfaces).

Quote
so you don't have to measure in exactly the same place twice. I guarantee you're not doing that with your calipers in most cases.
i agree! And yet you can hand me a steel rod <2" in diameter, and I'll tell you what it is within +- half a thou. Using only a $10.00 pair of calipers and nothing else to reference. And I'll lay down money. IOW, none of my calipers have a noticeable problem in this regard. If the jaws were slightly off parallel/flat, I imagine I would just fix it. It's just steel, and very thin pieces at that.

I believe the Mit will be more accurate beyond 3". For smaller measurements, I think my calipers couldn't get much better. It's possible I hit the lottery. Or maybe these things have gotten better since you formed your opinion.

Quote
Maybe it would be faster or easier to use the Mitutoyo (incorrectly/sloppily) and get the right reading?
When I said this, believe me. I did not mean to imply you are doing it wrong. I was speculating that this is one way in which the Mitutoyo could be a superior tool, despite my own experience of cheap calipers being on the money (at least where 99% of most peoples' uses would matter. Not every day the average Joe needs 1 mil precision on 2+" thick stock of anything.) As in maybe they get a solid reading without as much attention or care.

I've never touched a Mitutoyo nor ever been a professional machinist. The closest I get is grinding things on the redneck lathe or the router table. Yes, it's possible to grind steel to less than 1 mil precision with a drill and a dremel. And a $10.00 caliper.
Title: Re: Digital calipers — what to buy?
Post by: tooki on July 20, 2018, 01:51:18 pm
Thanks for the replies, everyone! So far, I’m leaning towards the Sylvac (for the giant digits, and being fairly locally made), but they are sold without thumbwheels, which are an accessory you can install after the fact — in theory. Nobody seems to actually sell the thumbwheels...  >:(

As for Mitutoyo, upon closer inspection, almost all of the models they sell here in Europe are metric-only. I don’t need inches often, but it’s definitely something I do need on occasion. So that rules out all but a few models. The standard one with inches is on sale through the end of the year, but currently sold out. :/

So I guess I’ll keep an eye on stock levels and prices and see if I can find somewhere that has the various brands available to try out!

If your calipers are skipping 0.1" here and there, it's possible your calipers are dirty. Doesn't matter if they're Mitutoyo or $10.00 calipers. Grease or dirt can skew the reading by changing the capacitance. Bad enough, and maybe the micro gets confused. The other potential issue is slow wakeup. If they are the kind that turn on automatically when you move them, maybe you are just moving them too fast from sleep. I always check they're zeroed after turning them on, anyway.

Come to think of it, the erroneous reading thing was a small but real, nagging fear before I switched to the silver oxide LR44. Aside from simply lasting much, much longer, I think the silver oxide produce a more flat voltage and don't screw with the microcontroller so much at their end.  These should be standard fare for calipers.
Trust, me, the problems aren’t a PEBKAC, they’ve been fussy since I bought them. The problem gets worse (far worse!) when the battery gets low, but even with a new one, I start with them zeroed out, and after a few slides back and forth doing measurements, it’s at 5.08mm when closed. Repeated opening and closing will eventually add more 5.08mm increments. (Only rarely, it adds “just” 2.54mm steps...) I think I figured out that holding them a certain way (I forget how) exacerbates the problem. But above all, I’m not talking about “here and there” as in maybe one measurement in 100. We’re talking about it being so often (1 in 5 maybe?) that I am forced to compare every measurement to the physical scale to make sure it hasn’t jumped 5mm...

I just got an SR44 (silver oxide; LR44 is alkaline) since the battery is dead, so they can hold me over until I get a good caliper!

I've never touched a Mitutoyo nor ever been a professional machinist. The closest I get is grinding things on the redneck lathe or the router table. Yes, it's possible to grind steel to less than 1 mil precision with a drill and a dremel. And a $10.00 caliper.
I was pleasantly surprised at just how much smoother the Mitutoyo feels compared to my $15 Aldi ones, or even than the $80 ones at the local retail tool shop. Like, we’re not talking a subtle difference. (And had I not already known what the Mitutoyo felt like, I would have called the $80 ones smooth.)
Title: Re: Digital calipers — what to buy?
Post by: KE5FX on July 20, 2018, 09:15:35 pm
As for Mitutoyo, upon closer inspection, almost all of the models they sell here in Europe are metric-only.

Wow, that's weird as hell.  I wonder why someone would even make a digital caliper without a switch. :(  An obscure EU rule of some kind, perhaps? 

Certainly no one would buy a (professional-grade) caliper over here that couldn't be switched to metric.
Title: Re: Digital calipers — what to buy?
Post by: tooki on July 20, 2018, 10:03:20 pm
As for Mitutoyo, upon closer inspection, almost all of the models they sell here in Europe are metric-only.

Wow, that's weird as hell.  I wonder why someone would even make a digital caliper without a switch. :(  An obscure EU rule of some kind, perhaps? 

Certainly no one would buy a (professional-grade) caliper over here that couldn't be switched to metric.
I doubt it’s a rule, since Mitutoyo sells a few switchable models here — and all the other brands seem to be switchable across the board.

The only reason I can think of — and this is straining my brain, as a usability professional — is to eliminate potential measurement error by accidentally being in the wrong unit. Since users outside of North America will be using metric 99.99% of the time, for them a switch is a potential source of errors with essentially no benefit.

That or it saves 22¥ on a button.
Title: Re: Digital calipers — what to buy?
Post by: Old Printer on July 27, 2018, 01:25:36 pm
Call me a shoemaker if you want, but I have a 6" electronic caliper from Harbor Freight (Central) that work fine fore me. I am not a tool and die maker, but I do have a good number of years experience in a machine shop and appreciate good tools. For me .001" is good enough and these are repeatable to half of that. I keep several batteries in the case so no worries about going dead. I have a 6"  Mitutoyo dial caliper that is better made, but for my day to day use these HF Centrals suite me just fine and cost about $35 so I don't have to worry about them.
Title: Re: Digital calipers — what to buy?
Post by: tooki on July 27, 2018, 01:50:43 pm
Call me a shoemaker if you want, but I have a 6" electronic caliper from Harbor Freight (Central) that work fine fore me. I am not a tool and die maker, but I do have a good number of years experience in a machine shop and appreciate good tools. For me .001" is good enough and these are repeatable to half of that. I keep several batteries in the case so no worries about going dead. I have a 6"  Mitutoyo dial caliper that is better made, but for my day to day use these HF Centrals suite me just fine and cost about $35 so I don't have to worry about them.
I don't need any added accuracy. It's reliability that's driving me mad. (Did you read my original post?) I don't wanna have to buy three different cheapies to find one that works reliably, I'd just as soon buy one good one that I can rely on. (Now that, after owning the cheapies, I know it's a tool I use regularly.)
Title: Re: Digital calipers — what to buy?
Post by: Gyro on July 27, 2018, 07:08:45 pm
As for Mitutoyo, upon closer inspection, almost all of the models they sell here in Europe are metric-only.

Wow, that's weird as hell.  I wonder why someone would even make a digital caliper without a switch. :(  An obscure EU rule of some kind, perhaps? 

Certainly no one would buy a (professional-grade) caliper over here that couldn't be switched to metric.

Of course Japan is purely metric too, maybe they just don't see the need.
Title: Re: Digital calipers — what to buy?
Post by: KL27x on July 27, 2018, 08:06:33 pm
Funny, I just came across a post by a pretty famous Youtuber who owns a Bridgeport and a metal lathe. From this horse's mouth:

Quote
The extra $150 it costs to go from Harbor Freight quality to Mitutoyo quality isn't worth it. Unless you are feeding a tool fetish, which, I am.

I'm sure some people have a bad experience with cheap calipers. I bet there's someone at Mitutoyo customer service getting occasional complaints, too.

I'm surprised the battery didn't fix the skipping issue on OP's calipers. Well, it did sound pretty weird, though, what with the exact 5.08 mm offsets.

My 3 sets (and a digital depth/height gauge) are good AF; I can't imagine any different. Personally, I like the "buy 3 cheapie" but I'm fully indoctrinated to Amazon Prime and eBay. Click click. And end up more than likely with 3 good sets. :)
Title: Re: Digital calipers — what to buy?
Post by: metrologist on July 27, 2018, 08:14:21 pm
I still like my $30 Swiss Precision Instruments calipers. I also like my expensive Brown&Sharp calipers too, but they do not have a thumbwheel option, which I do like. The B&S feel a little better, but the readings are the same between them, and have been for a decade.
Title: Re: Digital calipers — what to buy?
Post by: KL27x on July 27, 2018, 08:32:50 pm
If you have had a bad initial experience, I can fully appreciate how hard it is to believe that these are (maybe) generally good.

Mine have all been perfect out of the box, yet it took several hours of doing actual precision work before I trusted that first one for shit. It was hard to wrap my brain around the precision/repeatability for the $ and the enormous price differential btn them and the professional brands. It took awhile to accept that I can accurately "see" down to really less than half a mil (with multiple measurements near the same location*). We all think we're objective, but our minds are easily influenced. And those numbers on the display don't really mean anything until after they've proven repeatable and on the money, time after time. One bad experience could wreck that trust forever.

*I can map out the topology. Unevenness, taper, out or roundness, down to the half mil, and it is repeatable. Rounding off those digital steps, you can "see" where you are halfway between. And by varying pressure on the thumbwheel, you can get a feel for where in that last half mil you are, even in a single measurement, by where it blinks between two steps. This is not impressive, in itself. It's just a number, and it will change, somewhere. It's impressive that IME, the calipers are precise enough that this is meaningful. On small steel parts, anyhow.
Title: Re: Digital calipers — what to buy?
Post by: KE5FX on July 27, 2018, 09:39:45 pm
As for Mitutoyo, upon closer inspection, almost all of the models they sell here in Europe are metric-only.

Wow, that's weird as hell.  I wonder why someone would even make a digital caliper without a switch. :(  An obscure EU rule of some kind, perhaps? 

Certainly no one would buy a (professional-grade) caliper over here that couldn't be switched to metric.

Of course Japan is purely metric too, maybe they just don't see the need.

Machining will never go 100.000% metric.  The "thou" will still be in use when the Last Trump sounds, because there's nothing in the metric system that works as well for real-world measurements.
Title: Re: Digital calipers — what to buy?
Post by: orin on July 27, 2018, 10:35:22 pm
Call me a shoemaker if you want, but I have a 6" electronic caliper from Harbor Freight (Central) that work fine fore me. I am not a tool and die maker, but I do have a good number of years experience in a machine shop and appreciate good tools. For me .001" is good enough and these are repeatable to half of that. I keep several batteries in the case so no worries about going dead. I have a 6"  Mitutoyo dial caliper that is better made, but for my day to day use these HF Centrals suite me just fine and cost about $35 so I don't have to worry about them.


I have a 6" Mitutoyo electronic caliper, but hardly ever use it... mostly I use a cheap Harbor Freight one.  For the measurements I do, it doesn't matter.  The only problem with the HF calipers is that they eat batteries so I have to keep spares around.

FWIW, at the local tech college, they used HF dial gauges.  The instructor, who had compared them to far better gauges of his own, said they couldn't find anything wrong with the HF gauges, and if a student dropped or otherwise broke one, they just went out and bought another... (or pulled one from the cupboard that they'd got when they were on sale at $9.99).
Title: Re: Digital calipers — what to buy?
Post by: KL27x on July 28, 2018, 01:23:43 am
Quote
The "thou" will still be in use when the Last Trump sounds, because there's nothing in the metric system that works as well for real-world measurements.
Your statement would hold more weight if your location flag wasn't USA. :)

I grew up with imperial, so I figured I might be biased for my affinity to the thou/mil, even though I didn't really use/comprehend this unit until perhaps the last ten years, getting more into pcb design and fab, where I tend to think and work in mils.

This is the main reason I avoided buying the large digit calipers that are avail, now. The big digits stopping at hundredths doesn't make sense to me for most anything I would use calipers for. 
Title: Re: Digital calipers — what to buy?
Post by: blueskull on July 28, 2018, 01:26:34 am
Quote
The "thou" will still be in use when the Last Trump sounds, because there's nothing in the metric system that works as well for real-world measurements.
Your statement would hold more weight if your location flag wasn't USA. :)

I grew up with imperial, so I figured I might be biased for my affinity to the thou/mil, even though I didn't really use/comprehend this unit until perhaps the last ten years, getting more into pcb design and fab, where I tend to think and work in mils.

This is the main reason I avoided buying the large digit calipers that are avail, now. The big digits stopping at hundredths doesn't make sense to me for most anything I would use calipers for.

 :palm:

Another imperial vs metric debate is about to unfold.
Title: Re: Digital calipers — what to buy?
Post by: KL27x on July 28, 2018, 01:34:27 am
Hah, no. It's just that thous/mil happens to be very convenient size and has a one syllable name. In CAD work of smaller things, it's convenient because you don't to bother with decimal points or zero place holders.

Metric has the "mic," but for most people's grunt work in machining/fab, it's rather small to be useful. Hundredths of millimeters just don't roll off the tongue, and no one makes calipers with that level of resolution or accuracy, which right there makes it not too convenient of a unit. But still, I wonder if we could go back in time, they would have made the metric mic a hundredth of a mm instead of a thousandth. I suppose it's short for micrometer. So it is what it is. Not as generally or widely useful as a thou.

I believe even in the EU engineering/machining worlds, a "thou" is universally understood and not confused with metric.

Title: Re: Digital calipers — what to buy?
Post by: langwadt on July 28, 2018, 01:47:58 am
As for Mitutoyo, upon closer inspection, almost all of the models they sell here in Europe are metric-only.

Wow, that's weird as hell.  I wonder why someone would even make a digital caliper without a switch. :(  An obscure EU rule of some kind, perhaps? 

Certainly no one would buy a (professional-grade) caliper over here that couldn't be switched to metric.

Of course Japan is purely metric too, maybe they just don't see the need.

Machining will never go 100.000% metric.  The "thou" will still be in use when the Last Trump sounds, because there's nothing in the metric system that works as well for real-world measurements.

bollocks, there is only one real reason not to go all metric, that is all the old machines and  tools that would need to be replaced

anything modern will do both

Title: Re: Digital calipers — what to buy?
Post by: KE5FX on July 28, 2018, 01:49:44 am

bollocks, there is only one real reason not to go all metric, that is all the old machines and  tools that would need to be replaced

anything modern will do both

No 'bollocks' about it.  Ask any actual machinist.

The lack of a unit between a millimeter and a micron is indeed a big problem.
Title: Re: Digital calipers — what to buy?
Post by: KL27x on July 28, 2018, 02:11:35 am
^
Example
"I want this part to be X, to the nearest thou."

Vs
"I want this part to be X, plus or minus X hundredths of a millimeter."

It's just dumb luck that the thou is what can be machined to, efficiently, without costing a fortune. (Or maybe it is divine intervention?) Whereas this translates to a weird multiple of hundredths of millimeters.

Title: Re: Digital calipers — what to buy?
Post by: langwadt on July 28, 2018, 02:19:22 am

bollocks, there is only one real reason not to go all metric, that is all the old machines and  tools that would need to be replaced

anything modern will do both

No 'bollocks' about it.  Ask any actual machinist.

The lack of a unit between a millimeter and a micron is indeed a big problem.

huge problem, that is why no countries except Liberia, Myanmar and the USA has ever done anything... /s

Title: Re: Digital calipers — what to buy?
Post by: blueskull on July 28, 2018, 02:29:07 am
Who cares? For a rough estimation, 4 mils is 0.1 mm, period.
If anyone can't easily juggle between mil and mm, he/she should better be away from heavy machinery.
Title: Re: Digital calipers — what to buy?
Post by: KL27x on July 28, 2018, 02:43:52 am
Quote
Who cares?
People? :-// Why do you care that we care?  :-DD :-DD

Working in 1/4 tenths of mm is brilliant. This has all the disadvantages of both systems rolled up into one.

Now that you mention this, I seem to recall reading about this actual unit. Some nerds created it, dubbing it the metric mil. Maybe it is my imagination, because it doesn't pull anything on Google. Or maybe this is what caused the Hubble Telescope Fiasco and no one uses it anymore.
Title: Re: Digital calipers — what to buy?
Post by: SparkyFX on July 28, 2018, 03:14:18 am
As the battery drains, it gets more and more sensitive to spurious jumps.
The rare use and the weak battery life made me go back to manual tools...

Quote
I assume IP67 rating keeps dust out and theoretically improves longevity, right?
It keeps dust and coolant fluid out of the electronics, not off the encoder´s surface.

Quote
What about jaw shape?
Micrometer resolution? Square vs round depth gauge? Carbide jaws? (Expensive!)
The typical applications for calipers is diameter measurement, hole depth, thread spacing, thickness or simply length.
What is best for you.... you got to know that.

Carbide jaws might make sense if you happen to work with hardened steel or hard materials like tungsten or carbide, so that you don´t scratch the calipers with every measurement and start to measure the burr or dents in their surface.

Quote
Some models list “inductive” sensing. Others “absolute positioning”. What should I look for?
Inductive means that the reading head will only fail with conductive or magnetized dirt on the encoder, whilst other methods might have a problem with coolant or forms of dust. Absolute means the signal is encoded in a way to keep the distance even when removing the battery, no zeroing required?!

Quote
I don’t think I need a micrometer, but is it worth having?
It´s biggest advantage over calipers is the hardened surfaces, the high repeatability (micrometers often have a ratchet which ensures the same clamping pressure every time), the parallel surfaces and movement (calipers do need quite some play to move) or with variants that allow attachments the shape that matches the application. Check out universal micrometers for that.

Quote
My actual needs are modest. I’m measuring mostly things like screws, components, cutouts, etc. But I absolutely hate using shitty tools, I want something dependable and that feels good in my hand, where the parts slide smoothly without wobble, with great usability.
The sharp edges of calipers are nice to get into tight space, as long as you hit the proper angle the reading will be good, but once you need to move while on the surface to get the longest or shortest point the clamping pressure varies and repeatability suffers or you cut into the part. Machinists tend to use the combination of telescoping gauges with micrometer or inside micrometers or gauge blocks instead.

It´s that angular error that makes calipers less precise than other ways of measuring a distance.

Title: Re: Digital calipers — what to buy?
Post by: blueskull on July 28, 2018, 03:21:29 am
Now that you mention this, I seem to recall reading about this actual unit. Some nerds created it, dubbing it the metric mil.

Makes sense. Just like in ICs, the old pitch values were 2.54mm and 1.27mm, while the next generation changed to not 0.635mm, but a more metric friendly 0.65mm, and all future pitches are all metric (0.5mm, 0.4mm, 0.35mm, 0.3mm).

Many PCB engineers in China say x mils, but they really mean x*25 um. Similarly, Chinese PCB fab houses use the same convention. If you pay for a 6 mil process, they will not mandate 152.4 um spacing, instead, they will allow 150 um spacing.
Title: Re: Digital calipers — what to buy?
Post by: KL27x on July 28, 2018, 04:16:27 am
Quote
Many PCB engineers in China say x mils, but they really mean x*25 um. Similarly, Chinese PCB fab houses use the same convention. If you pay for a 6 mil process, they will not mandate 152.4 um spacing, instead, they will allow 150 um spacing.

Makes perfect sense. I imagined in metric countries machinists would mix it, as in "5.35 millimeters, rounded to a thou/mil." vs saying +-0.25mm.

And in US, in many industries metric units may be more convenient, and not just sciency stuff. Metal platings are often stated in micrometers. It's just a better sized unit for that. This is the reason we have centimeters and millimeters and not just scientific notation *10^x.

Total aside, and you probably don't even know. But if anyone in China or EU knows this....
Why can I buy 6mm die grinders and die grinder bits imported from China? Endmills and engraving bits, too? For rotary tools, plenty of 3mm bits. But no metric router bits? It seems like if China used them, they'd also be exported to the US. I understand that Australia switched over to metric in the 60's, but they also use imperial router bits. I just find it strange die grinders and mills in metric, but not routers. Is this just a lack of import/export? Or do people actually use imperial/SAE routers/bits in China?



Title: Re: Digital calipers — what to buy?
Post by: tooki on July 28, 2018, 04:33:40 am
Funny, I just came across a post by a pretty famous Youtuber who owns a Bridgeport and a metal lathe. From this horse's mouth:

Quote
The extra $150 it costs to go from Harbor Freight quality to Mitutoyo quality isn't worth it. Unless you are feeding a tool fetish, which, I am.

I'm sure some people have a bad experience with cheap calipers. I bet there's someone at Mitutoyo customer service getting occasional complaints, too.

I'm surprised the battery didn't fix the skipping issue on OP's calipers. Well, it did sound pretty weird, though, what with the exact 5.08 mm offsets.

My 3 sets (and a digital depth/height gauge) are good AF; I can't imagine any different. Personally, I like the "buy 3 cheapie" but I'm fully indoctrinated to Amazon Prime and eBay. Click click. And end up more than likely with 3 good sets. :)
I don’t want to waste time dicking around. I don’t want three sets. I want one that works 100%. And I’m not in USA. Amazon doesn’t have Prime in Switzerland.

The cheapies have been dicky since day 1. New batteries have never fixed it.

And they’re not as smooth. I want smooth.

I kinda feel I’ve said these things already...
Title: Re: Digital calipers — what to buy?
Post by: tooki on July 28, 2018, 04:36:32 am
If you have had a bad initial experience, I can fully appreciate how hard it is to believe that these are (maybe) generally good.

Mine have all been perfect out of the box, yet it took several hours of doing actual precision work before I trusted that first one for shit. It was hard to wrap my brain around the precision/repeatability for the $ and the enormous price differential btn them and the professional brands. It took awhile to accept that I can accurately "see" down to really less than half a mil (with multiple measurements near the same location*). We all think we're objective, but our minds are easily influenced. And those numbers on the display don't really mean anything until after they've proven repeatable and on the money, time after time. One bad experience could wreck that trust forever.
Your wording makes it sound as though I were a survivor of domestic abuse or something...

I just don’t want dicky tools. And I’m not willing to invest time or money in tools that maybe will be OK. I want guaranteed good.
Title: Re: Digital calipers — what to buy?
Post by: tooki on July 28, 2018, 04:38:01 am
:palm:

Another imperial vs metric debate is about to unfold.
And you nailed your prediction.


Folks, can we kill the metric vs imperial/customary debate? It’s of absolutely no interest to this discussion, and will end up with the thread being closed... Please knock it off.
Title: Re: Digital calipers — what to buy?
Post by: KL27x on July 28, 2018, 04:51:52 am
Quote
Your wording makes it sound as though I were a survivor of domestic abuse or something...
I'm sorry, Tooki, you take this personally.

In American english, we often say "you" but are not talking to you, the individual. I'm speaking in a general sense as part of a larger discussion. Technically we have a word for this, "one," or you could also replace "you" with "a person." But most people don't talk like this in casual discussion in the last 50 years. I have already read your reasons, and I am not trying to sway you. I was just discussing with the other people who are discussing the (current) topic.

Even when I mentioned you as OP or "OP's issue" I did it in the third person; I did so because I'm not speaking to you, directly, nor challenging your views or reasoning. I'm not trying to draw you into a debate or troll you. Just discussing. With other people who care to discuss. If that's not you, no need to get your feathers ruffled!

In fact, I fully comprehend when you said you have no issue with accuracy, just with the weird skipping thing.

Quote
Folks, can we kill the metric vs imperial/customary debate? It’s of absolutely no interest to this discussion, and will end up with the thread being closed.
:-//

AFAIC, we were having a civil and interesting discussion and potentially learning things?

You got a lot of good suggestions and info, and you already bought a new pair of calipers. What left of interest is there to "this discussion" which you are waiting to hear, but which this current topic is ruining for you?

No one needs to close it if it gets derailed for no reason. It will die on its own.

Title: Re: Digital calipers — what to buy?
Post by: KL27x on July 28, 2018, 09:01:56 am
Hey, hold on a sec.  |O

Tooki, you live in Switzerland. Your country has been metric since the 1800's, right? You could help settle a bet!  :-DD :-DD

And just a reminder. You opened up this conversation with your reasoning for not going with Mitutoyo.
Title: Re: Digital calipers — what to buy?
Post by: tooki on July 28, 2018, 12:31:10 pm
Quote
Your wording makes it sound as though I were a survivor of domestic abuse or something...
I'm sorry, Tooki, you take this personally.

In American english, we often say "you" but are not talking to you, the individual. I'm speaking in a general sense as part of a larger discussion. Technically we have a word for this, "one," or you could also replace "you" with "a person." But most people don't talk like this in casual discussion in the last 50 years. I have already read your reasons, and I am not trying to sway you. I was just discussing with the other people who are discussing the (current) topic.

Even when I mentioned you as OP or "OP's issue" I did it in the third person; I did so because I'm not speaking to you, directly, nor challenging your views or reasoning. I'm not trying to draw you into a debate or troll you. Just discussing. With other people who care to discuss. If that's not you, no need to get your feathers ruffled!

In fact, I fully comprehend when you said you have no issue with accuracy, just with the weird skipping thing.

Quote
Folks, can we kill the metric vs imperial/customary debate? It’s of absolutely no interest to this discussion, and will end up with the thread being closed.
:-//

AFAIC, we were having a civil and interesting discussion and potentially learning things?

You got a lot of good suggestions and info, and you already bought a new pair of calipers. What left of interest is there to "this discussion" which you are waiting to hear, but which this current topic is ruining for you?

No one needs to close it if it gets derailed for no reason. It will die on its own.
I’m an American living in Switzerland, whose native language is English, so please don’t attempt to lecture me on it.

Whether you refer to me as “tooki” or “the OP”, you’re still referring to me. So yes, I can see why I might think you’re talking about me and not a general, nonspecific person. Whether you use second or third person is irrelevant. 

I didn’t buy new calipers yet. No idea where you got that idea.

Hey, hold on a sec.  |O

Tooki, you live in Switzerland. Your country has been metric since the 1800's, right? You could help settle a bet!  :-DD :-DD

And just a reminder. You opened up this conversation with your reasoning for not going with Mitutoyo.
What bet would I be able to settle??

All I said that inches is a requirement unmet by most (not all!) Mitutoyo models available here. I did NOT ask for a debate of the virtues of each system. Don’t try and make it out as though it’s my fault.

It’s just that these debates end up going nowhere, usually with Americans getting pissed off becsuse others verbally abuse us for being too “stupid” to switch. And then if you try to show them examples where they still use non-metric in a metric country, they laugh it off and call you stupid again. (Yes, I’ve had this discussion countless times, online and IRL, and I have found that metric champions are overwhelmingly condescending and resistant to objective analysis.)
Title: Re: Digital calipers — what to buy?
Post by: KL27x on July 28, 2018, 01:12:21 pm
So an expat. You don't count, then. You're just another dumb american like me. :) From the lack of switchable models, I supposed the Swiss don't have a whole lot of use for imperial calipers, even despite the holy mil. :)

(I am still curious if Swiss use metric router bits. 6mm and 12mm shanks? Or 1/4", 1/2"?)

Quote
It’s just that these debates end up going nowhere, usually with Americans getting pissed off becsuse others verbally abuse us for being too “stupid” to switch. And then if you try to show them examples where they still use non-metric in a metric country, they laugh it off and call you stupid again.
I think you're onto something. It's like an endless loop. So depressing....

I got it. We Americans need to take the initiative and preemptively call them stupid!!!
Hey, y'all. Americans here. You guys are stupid! Stoopid!! All of ya's dirty condescending rats, every last one of ya's! 

Yep. This one is going to be different. I can feel it!



... coming in the air, tonight... Oh, Lord! Dun, dun, dun.


 I been waiting for this moment... all my life...Oh, Lord!





Title: Re: Digital calipers — what to buy?
Post by: David Hess on July 28, 2018, 05:31:34 pm
Folks, can we kill the metric vs imperial/customary debate? It’s of absolutely no interest to this discussion, and will end up with the thread being closed... Please knock it off.

There is no reason both sides cannot be wrong.  We should have had a metric like system using base-12 (https://en.wikipedia.org/wiki/Duodecimal#Duodecimal_metric_systems).
Title: Re: Digital calipers — what to buy?
Post by: KL27x on August 09, 2018, 03:02:49 am
https://youtu.be/mBKZvAAp-tk?t=13

Surprise, surprise! Mitts ship with an SR44, whadya know. A $150.00 genuine Mit doesn't save 20 cents by including a terrible battery. (Apparently the $75.00 knockoffs do, lol). This has more to do with the difference in battery life than anything else.

Tooki, this guy has some tool love for iGauging. And if you like battery life, there's an iGauging that takes a CR2032!

Here's a vid from him which you might find of interest.
https://youtu.be/1yqZx_FNbSs?t=144
Timestamped at a point where he shows a potential source of error with the cheapos.
(Interestingly enough, I did this exact test with all 3 of my $10.00 calipers, and my set of feeler gauges. They measure exactly the same using the entire jaw or just the tips. Every one, down to the half mil, except for one of them. In fact, I have to carefully twist the feeler gauge to exactly perpendicular when measuring at the very tip in order to find the lowest reading, otherwise I can get a reading that is 2-3 mils too high due to being slightly out of square. The lowest reading I could get was invariably either exactly the same as the full jaw reading except in one of the calipers, with some of the shims, the lowest reading I could get was half a mil higher than the full jaw reading.
Only when I clamp down on the thumbwheel unreasonably hard can get the reading to drop below the right number, up to 2-3 mils low with enough force.
No daylight or misasligment on the inside jaws on any of mine, neither.

All of these observations pertain to even first pair that is maybe 10 years old. I was most worried about my newest one, TBH. It has noticeably more twisting slop, if you torque the jaws. But it gives the right reading, just like the others.  I guess it's just a bit of a crapshoot, but for $10.00.... :-//
Title: Re: Digital calipers — what to buy?
Post by: PaulMC on September 27, 2019, 01:45:28 pm
they often skip, so returning to zero suddenly the number has gone up in  2.54mm/0.1” steps, usually 5.08mm.

I stumbled upon this thread in my search of a fix for a cheap pair of calipers I have which also skip by multiples of 5.08mm. Ultimately, I was able to resolve the problem by fixing a piece of Kapton / polyimide tape over the position-sensing PCB contained within the digital readout housing (PCB shown here: https://woodgears.ca/caliper/circuit_back.jpg). The tape is now located between that PCB and the 6" ruler arm of the calipers. Prior to this, I cleaned the PCB and replaced the battery.

Note that I found a similar fix elsewhere recommending placing a piece of scotch tape in the same location as I have described. I tried this fix as well, but found that it did not resolve my problem. The same fix using the Kapton tape resolved my issue. Hope this helps someone else looking to save their cheapo measuring tool.
Title: Re: Digital calipers — what to buy?
Post by: tooki on October 04, 2019, 04:02:02 pm
they often skip, so returning to zero suddenly the number has gone up in  2.54mm/0.1” steps, usually 5.08mm.

I stumbled upon this thread in my search of a fix for a cheap pair of calipers I have which also skip by multiples of 5.08mm. Ultimately, I was able to resolve the problem by fixing a piece of Kapton / polyimide tape over the position-sensing PCB contained within the digital readout housing (PCB shown here: https://woodgears.ca/caliper/circuit_back.jpg). The tape is now located between that PCB and the 6" ruler arm of the calipers. Prior to this, I cleaned the PCB and replaced the battery.

Note that I found a similar fix elsewhere recommending placing a piece of scotch tape in the same location as I have described. I tried this fix as well, but found that it did not resolve my problem. The same fix using the Kapton tape resolved my issue. Hope this helps someone else looking to save their cheapo measuring tool.
Thanks for the tip. I just applied it, let's see if it does anything...