What size caliper?

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.
 
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.
 
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.
 
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.
 
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.
 
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.
 
Edit: old post. ....never mind.....
 
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I have 6", 8", and 12". The 8" gets the most use and the 12" comes in second.
 
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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