# What size caliper?



## magu (Nov 27, 2017)

Up until this point I have only had an unbranded dial caliper, for anything "important" I've begged and borrowed tools from some real machinist friends. That being said, I would like to buy a decent caliper to have around the shop and am stuck on what size to go with. 6" calipers are plentiful, and therefore a bit cheaper, but they are limited to... 6" 12" calipers are great, but if I'm measuring something still on a machine, I am afraid their size will become a hindrance. I am leaning towards an 8" model; while it isn't "that much more" it will allow me to measure things in the ~6" OAL range. Anyone have any thoughts?


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## Dan_S (Nov 27, 2017)

My recommendation would be to save for a really nice 6" with carbide jaws. 

I have several 6" calipers and an 8", the 8" probably gets used less than once a year.


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## dlane (Nov 27, 2017)

If it were me Ied go with a 6" dial , and a 6" electronic three way " decimal, metric, fractions, 
I've had an abused chi dial caliper that are every bit as accurate as my brown & sharp good ones that live in the drawer until needed


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## Tozguy (Nov 27, 2017)

I never needed more than a Mitu 6'' dial but bought a 4'' electronic and then a 6'' igaging electronic just because. The 4'' is used mostly in tight quarters as when measuring work on the lathe.


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## mikey (Nov 27, 2017)

Tozguy said:


> I never needed more than a Mitu 6'' dial but bought a 4'' electronic and then a 6'' igaging electronic just because. The 4'' is used mostly in tight quarters as when measuring work on the lathe.



I'm with Tozguy. I use a 6" calipers the most, a 4" for lathe work and a 12" Mitutoyo for when I have to measure backing plates and such on the lathe. I prefer analog/dial calipers or vernier calipers.


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## Firestopper (Nov 27, 2017)

I have 6" Mitutoyo digital and 8"dial but a great bag for your buck is the Igaging absolute found all over the net.
These are very accurate and affordable. I purchased a 12" and really like it. 
https://www.ebay.com/itm/iGaging-Ab...186392&hash=item20e833fca6:g:wAIAAOSwirZTsNYu


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## Technical Ted (Nov 27, 2017)

6" is the size I use the most. I have a set of Helios vernier, B&S dial, Starrett dial, but the set I use the most are my absolute digital iGaging. For me, an absolute set is the way to go since you don't have to constantly re-zero them. The price is right and the quality is very good.

https://www.amazon.com/iGaging-ABSO...id=1511826842&sr=8-1&keywords=igaging+caliper

Ted


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## rgray (Nov 27, 2017)

I have a 6"caliper with every machine. Two for the main lathe (left & right). Cheapie electronic.
Save your money for micrometers.


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## royesses (Nov 27, 2017)

I have 6" and 12" digital and 6" dial types. I definitely need to get a 4" for work on the mini lathe and mini mill. I sometimes need to do acrobatic contortions to read the 6" on parts still in the lathe. Aint good for an old man to do. Love the Mitutoyo's and the Shars Aventor 12" is also very nice. The I'gaging 6" is a keeper too.

Roy


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## Holescreek (Nov 27, 2017)

I still use the 6" Mitutoyo dial calipers I bought new in 1981 every single day. I have a couple sets of digitals (very old 8" and newer 6") that I only break out if I need quick metric readings (I.E. Never).  I also have a Mitutoyo 12" dial caliper and an import 24" caliper.  Cheap digital calipers are great for cutting up to make into readouts for mill spindles and lathe tailstocks.  Batteries never go dead in a dial caliper and when I need 4 place accuracy I switch to micrometers.


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## EmilioG (Nov 28, 2017)

If I had to purchase one caliper, it would be an 8" Mitutoyo digital, more versatile. The 6" are too short for all around work, IMHO, you will quickly
run out of "room" and you don't have to extend the jaws too far for more accurate measurements.  The 6" caliper is not as accurate
at 5" or more, at the end of it's travel.  When you have to measure over 5"-6", you'll wish you had the 8".  Much easier to use.
The 6", you run out handle space quickly, very little beam left to hold. The 8" gives me plenty to hold, even with a 5" measurement.

Also have a 6" dial caliper. The Mitutoyo digitals are very accurate and last a long time., larger jaws than a 6" also.


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## woodchucker (Nov 28, 2017)

magu said:


> Up until this point I have only had an unbranded dial caliper, for anything "important" I've begged and borrowed tools from some real machinist friends. That being said, I would like to buy a decent caliper to have around the shop and am stuck on what size to go with. 6" calipers are plentiful, and therefore a bit cheaper, but they are limited to... 6" 12" calipers are great, but if I'm measuring something still on a machine, I am afraid their size will become a hindrance. I am leaning towards an 8" model; while it isn't "that much more" it will allow me to measure things in the ~6" OAL range. Anyone have any thoughts?


That will depend totally on what you work with.
Me, most of my work is in the 6" range.
So 6" works for me.
I don't think Carbide jaws are necessary.  If you work on large items a 6 and 12 would cover the range, while an 8 won't cover the 12, and your only gaining 2 inches over a 6.


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## Dan_S (Nov 28, 2017)

@magu

I got this in an email this morning, Travers is offering up to 50% off on calipers today only.
https://www.travers.com/email-17112...77472&utm_medium=email&utm_source=emailvision


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## Nogoingback (Nov 28, 2017)

EmilioG said:


> If I had to purchase one caliper, it would be an 8" Mitutoyo digital, more versatile. The 6" are too short for all around work, IMHO, you will quickly
> run out of "room" and you don't have to extend the jaws too far for more accurate measurements.  The 6" caliper is not as accurate
> at 5" or more, at the end of it's travel.  When you have to measure over 5"-6", you'll wish you had the 8".  Much easier to use.
> The 6", you run out handle space quickly, very little beam left to hold. The 8" gives me plenty to hold, even with a 5" measurement.
> ...




+1 on the Mitutoyo 8".  I bought one when my 6" dial caliper wasn't long enough for some jobs I was doing.  I still use the dial 
caliper for some things, but I like the digital a lot.  If you do much work with metric stuff, they're nice because it does the math
for you converting from metric to inches or vice versa.  There's no downside to the longer caliper: it just gives you more capability.


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## magu (Nov 29, 2017)

Hmmm, much food for thought. Thank you all for your reply(ies). 

The general consensus seems to be 6", with some detractors. I was originally pretty set on a Mitutoyo digital based on pricing I had originally seen, but it seems the market is flooded with Chinese copies. I'm sure if I go to a reputable seller I can get a genuine one, but that also raises the price. I'm not necessarily opposed to buying a set of Chinese digital calipers, but I would buy an Igaging or Shars Aventor set that openly states what they are rather than a fake knockoff. 

A few comments got me thinking that maybe I should just get a decent dial caliper instead. There is nothing wrong with a dial caliper, and I am comfortable using them, they just aren't as new and flashy. So back to the interwebs I went thinking "I'll check out Mitutoyo, they're a good brand and not as pricey as the American/European brands" well it seems all their dial calipers these days are made in Brazil not Japan and have quality reviews to match. 

All that rambling aside, I'm not much closer to a resolution than I was before.  I'm thinking maybe the best course of action would be to find a nice used set of dial calipers Mitutoyo, Starrett, B&S, Fowler etc. Is there anything to be particularly concerned about in buying used calipers?


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## Holescreek (Nov 29, 2017)

One comment was made that I can't let go unchallenged.  Someone stated that calipers weren't as accurate near the end of their travel.  As someone that has repaired and calibrated hundreds of digital calipers I know for a fact that the problem of accuracy is not with the caliper, it is with the user.  The further you open the moveable jaw the less there is for the user to hang onto with their right hand for thumb leverage.  If accuracy is required it's best to measure "wide open" with two hands, one holding each jaw.  It's very easy to see the result holding the caliper each way on a 6" standard.


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## Bob Korves (Nov 29, 2017)

A dial caliper can be fragile, and expensive to repair.  It does not work well for metric/imperial, rather either/or.  I am using a pair of HF 6" digital calipers I got about 5 years ago.  Still going strong, smooth, no issues, more than accurate enough for anything a digital caliper should be trusted to measure.  It is still on the original battery, and it came with a spare.  It cost $10 on sale, less 20% coupon, and a free flashlight with a coupon as well.  I also bought a spare one near the same time with the same coupons, it is still new in the box.  When my first one dies, I will not bat an eye as I throw it in the trash.  I scribe layout lines with it, even on a running lathe.  It has been used essentially every day, multiple times, and not babied.  I would not use an expensive digital caliper this way, so I do not have one...

My real backup caliper is an older 6" Kanon vernier model, made in Japan.  Nicely made, no batteries.  New in the box.  It will last though the apocalypse.   I have a couple nice dial calipers, also as new in the box, never touch them.


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## Dan_S (Nov 29, 2017)

Holescreek said:


> If accuracy is required it's best to measure "wide open" with two hands, one holding each jaw.  It's very easy to see the result holding the caliper each way on a 6" standard.



This is how I do it almost all the time, it makes it much easier to feel if you are square to the work.


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## Technical Ted (Nov 29, 2017)

I agree with Bob Korves... For me anyways, YMMV, but if I want something close I'll use my mikes. And, a lot of times even if I don't want something close I'll still use my mikes! 

But, I also realize that some people either don't want to or can't afford to buy mikes since the price can quickly add up.

Ted


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## BGHansen (Nov 29, 2017)

Not adding anything but I have non-digital 6" calipers at my lathes and mill (Mitutoyo with carbide jaws); those get the most use.  I have a set of 8" and 12" digitals and dial types at each lathe and mill also; those get little use.  Have a digital SPI 6" at my Clausing and a HF at the Grizzly.  Bought a 24" dial off eBay that's been used once.  I use a 4" dial at my layout bench a lot.  Also have a cheap carbon fiber digital 4" at my stock rack for quick diameter checks (tape measure also).

Bruce


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## magu (Nov 29, 2017)

I'm not too concerned about breaking or damaging them. I'm not too rough on tools, especially ones meant for measuring. I also don't mind the inch/metric thing. It's likely a product of when and where I went to school and work, but I'm quite comfortable with inches and metric in the same sentence or on the same drawing.


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## EmilioG (Nov 29, 2017)

Great read on calipers:
http://www.longislandindicator.com/p11.html

Caliper accuracy is only .001" at best, if the gage is not worn or bent.  Measuring a 6" part with a 6" caliper starts to get a bit awkward.
I work mostly in the 1-8" range when making parts, so my 6" dial and 8" digital covers it all.  Etalon makes the best dial caliper, IMHO, which are 6"
and have smaller tick marks for .005" range measurements. Very accurate.  Buying used can be a gamble, especially if parts are no longer available for your choice.

From LIIS:  "The *maximum error* on these B&S dial calipers is less than or equal to .001" for the first four inches. Above four inches, the maximum error is about .0012" If you need better accuracy, you should be using a micrometer instead of a dial caliper".

All calipers have a max. error. Calipers just aren't made for super accuracy.

Also from LIIS:

Dial Caliper Calibration

These instructions apply to mechanical as well as digital calipers.
Both the inside jaws and the outside jaws need to be calibrated, as well as the depth rod and the step measurement, if these are used. Calipers should be frequently checked for accuracy. They are more susceptible to damage than other tools.
To check for wear in the jaws, do this: clean them and close them. Then hold them up to the light and if they're worn you'll see light shining through the gaps. You can continue to use the calipers if you measure with the unworn surfaces. For total reliability, however, you'll have to send the calipers for servicing. The surfaces can be ground flat again.
For the outside jaws it's a simple matter of inserting a series of gage blocks between them and recording the caliper readings. They must not deviate by more than one graduation (.001") over the first 4" of range. From 4" to 8" the error may be .0015" (one and one-half graduation). From 8" to 12" the error can be .002". Accuracy may vary among different models and the manufacturer's specs should be consulted for this information. Take readings at 1-inch intervals. Three gage blocks (see below) of 1", 2" and 3" sizes will be all you need.
To calibrate the inside jaws you may use a set of ring gages. Do not rely on very small ring gages because the inside jaws can not accurately measure small inside diameters. Suitable ring gages are shown on page 163. If you invest in just one ring, make it the 2" size. You may also set a calibrated .0001" micrometer to 1" (and higher, if possible) and then use the inside jaws to measure this distance. Since the micrometer has a discrimination ten times that of the calipers, you'll get an accurate reading.
Repeatability means the dial hand returns to the same position on different attempts to measure the same gage block. If this fails, then you'll have to have the calipers serviced.


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## mikey (Nov 29, 2017)

Just an aside but the caliper I pull out when I want an accurate reading is a German-made Helios vernier caliper with fine adjust. Mine is exactly like this one: https://www.ebay.com/itm/HELIOS-9-7...966649?hash=item3f7b715d39:g:ZtwAAOSwrhBZB~TN

One common issue with calipers is that the jaws must be sit square on the part, and this can be more difficult than you might imagine. A fine adjust mechanism will square the caliper jaws to the part better than your hand and this leads to improved accuracy. The only problem with verniers is that your eyesight has to be good enough to read them, or use magnifiers like the rest of us old farts have to do. Used with care, vernier calipers will be just as accurate when your grandchild passes it on to his son.


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## EmilioG (Nov 29, 2017)

Good verniers are probably the best for accurate .001 measurements, but I'm too lazy to use them.
When I worked at inspection QC they had Helios verniers, they require some skill to use.
There are so many variations on the caliper. Just go to the Mitutoyo website and look at the caliper catalog .pdf

The OP is looking for a good first set. If you can, buy a new set. If you can find something good on Ebay check it out.
Most of Mitutoyos' new 505 series dial calipers are made in Brazil, but I;m sure they are excellent. The old B&S are great.
The new Mits 505 series, (Amazon.com)  are probably your best bet for the money. Just make sure you buy from and ships from Amazon.
Good luck. Let us know what you decide.


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## Tozguy (Nov 30, 2017)

magu said:


> I'm not too concerned about breaking or damaging them. I'm not too rough on tools, especially ones meant for measuring. I also don't mind the inch/metric thing. It's likely a product of when and where I went to school and work, but I'm quite comfortable with inches and metric in the same sentence or on the same drawing.



I use my cheap 4'' caliber when identifying screws and bolts, etc. By switching back and forth from inch to metric it makes it easier to decide which thread pitch gauge to grab for checking the threads.


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## projectnut (Nov 30, 2017)

I have several brands and style calipers around the shop.  The dial calipers are Mitutoyo and Starrett.  Both are the 6" variety.   I also have a number of cheapie electronic ones.  They are 6", 8" and 12".  The most used one is a cheapie 6".  Having said that I don't use any caliper for critical measurements.  To me it's difficult to get a truly accurate reading on a part chucked in a lathe with any caliper.  All critical measurements are done with micrometers.  They're easier to handle and far more accurate.

For micrometers I have both Starrett and Brown & Sharpe.  I have a set of 1" to 8" set of mechanical Starrett's that go down to ,0001".  I also have a few B&S 1" mics that permanently reside by the lathes and milling machines.


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## JPMacG (Jan 16, 2018)

Edit:  old post.  ....never mind.....


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## kd4gij (Feb 6, 2018)

I have 6", 8", and 12".  The 8" gets the most use and the 12" comes in second.


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## ariscats (Mar 1, 2018)

I do have the cheap variety electronic calipers in 10cm 15,20,30cm. Also two dial 15cm and two vernier of 20cm one Russian the other Polish.I found that the most unwanted feature of cheap Chinese calipers is that their "tail" is always slightly bent and also that the finish of the sliding  surface is not good.Both are repaired if you give some of your time and the improvement in smoothness and repeatability are impressive.More over for use on the the lathe consider calipers made for Left Handed people especially if you are ambidextrous.The most used size is 15 cm.Hoping i am not pirating the
thread.
Ariscars


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