# Using A Caliper: Pressure?



## Splat (Jun 5, 2014)

I don't like to admit it but I've shied away from using a caliper (or "calipers") for a long time because I could never seem to get consistent readings. I'd like to change that because I know I'm going to need to use calipers in the future. Let me ask you experienced guys... How do you properly use a (digital) caliper, or how much pressure should you apply when moving the jaws to the work? Thanks.


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## JimDawson (Jun 5, 2014)

The best way is to start with pieces that are known sizes, both square and round.  That way you can get the 'feel' of how to get the correct measurement.  If you have a set of micrometers, use them to find the sizes of you test pieces.  If not, maybe another local machinist can help you out with that.  Like any other manual measuring operation there is a technique that must be learned, it is not difficult, but does take some practice.

The most important thing is to make sure that you hold the caliper perpendicular to the piece that you are measuring.  To do this rotate the caliper side to side a bit while holding light pressure and look for the minimum reading.

The inverse applies to inside measurements, look for the maximum reading.

I hope this will help you to get started.


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## Splat (Jun 5, 2014)

JimDawson said:


> The best way is to start with pieces that are known sizes, both square and round.  That way you can get the 'feel' of how to get the correct measurement.  If you have a set of micrometers, use them to find the sizes of you test pieces.  If not, maybe another local machinist can help you out with that.  Like any other manual measuring operation there is a technique that must be learned, it is not difficult, but does take some practice.



That definitely helps. I'll get out my 1-2-3 blocks tomorrow and start on them. They're not top-shelf blocks but hopefully they're close to spec. Don't know why I didn't think of this! Thanks Jim.


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## JimDawson (Jun 5, 2014)

Splat said:


> That definitely helps. I'll get out my 1-2-3 blocks tomorrow and start on them. They're not top-shelf blocks but hopefully they're close to spec. Don't know why I didn't think of this! Thanks Jim.



My pleasure.  I just made an edit to my original post.  The next to the last sentence should have read ''The inverse applies to inside measurements, look for the maximum reading.''


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## xalky (Jun 5, 2014)

There is definitely a "feel" to using calipers, and every caliper has a slightly different feel. The more expensive calipers are more accurate, they seem less floppy. I have one good pair of dial calipers and a boat load of cheap digital ones. Whenever I need a  real critical measurement I always reach for a Mic, but calipers are so much quicker and more handy to use.

Sent from my SPH-L710 using Tapatalk


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## 12bolts (Jun 5, 2014)

My Mitutoyo dial caliper is my first go to measuring tool. I find that a firm but not heavy pressure on the jaws gives me consistent, accurate results. I dont use the thumbwheel so much as direct pressure on the back of the jaws with my fingers to get a reading.
I think if you spend the money on a quality caliper you should avoid problems with sprung jaws.

Cheers Phil


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## Don B (Jun 5, 2014)

xalky said:


> There is definitely a "feel" to using calipers, and every caliper has a slightly different feel



Defiantly true, what feels comfortable to one person doesn't to the next, my son and I both like quality tools, are hands are the same size, but we both have our preferred micrometers and calipers, when your testing your calipers check how the measurement is in a couple spots on the jaws (i.e at the tip of the jaw and farther up the jaw) with cheaper quality ones their can be a variance and even on better quality ones that have seen a lot of work or have been used rough.)
I've see different people use micrometers like there C clamps, LOL, they just crank on the thimble to force the reading they want, same with calipers.:rofl:
With a little practice and a light touch calipers will get you through most of your work without ever touching a micrometer.)


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## Andre (Jun 5, 2014)

Make sure your anvils (jaws) are very clean, as that can vary your measurement.

Put the piece in the jaws, and put light pressure on the part. Only use finger pressure, no need to groink on it. You know your taking the proper reading when you can (lightly) squeeze on the part and the reading does not change or until it feels like your taking a solid measurement. Practice on some gauge blocks, ball bearings (as units or single balls, roller bearing's internal and external races are precision ground), or anything you can check with a micrometer first.


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