Inside electronic micrometers jaw type questions

[jcfx]

I'm trying to understand how an electronic inside mic works, I recently purchased an import
and how to use it seems to elude me, the instructions that came with it were for outside mic
so it's of no use.

On a outside digital mic you close the anvils to check your start point ( zero )
then open it up to approx outside diameter and close to measure, but on a inside digital mic
where would one start from ?
Bringing the jaws closed to zero out, is not possible since once I hit the zero button I get an incremental
measurement of how far the movable jaw has traveled.
If I use the included gauge ( .2" ) as the start point, the readout is .2 and when I measure
the measured readout is correct.
I'm assuming that .2 is "zero" and all measurements have to start from there ?

How does say a Mitutoyo digital inside caliper work ?

[Magicniner]

How does say a Mitutoyo digital inside caliper work ?

You can zero electronic calipers anywhere you like, but since they do go down to zero that's irrelevant to inside micrometers which cannot read down to zero.

Mechanical inside micrometers come with a reference ring gauge to check they are correct close to their minimum size, exactly as your digital does, with a reference gauge and a micrometer which will set to that size then you have what you need,

- Nick

[GlennW]

I don't have an electronic digital internal micrometer, so a guess is all this is.

Close it and zero it.

Open it until it reads .2000" and hit the "Hold" button. (Freezes the readout while allowing the micrometer to be opened or closed)

Close it back up and then open it in the setting ring.

Release the "Hold".

It should now read .2000" inside the ring.

[Magicniner]

On a Mitutoyo digital electronic outside mic the Hold function holds the display reading but the electronics continue to log movement, when you release the hold it flips to the current measurement.

- Nick

[GlennW]

OK, I got out the 1"-2" Mit OD micrometer and it works as Magicniner described above. I had never really fiddled with the "Hold" function much, and didn't have the micrometer with me to play with.

So, here's my second guess...

It has an "Origin" button (that I have never fooled with either) as well as a "Zero" button.

Pressing the "Zero" button zero's everything and displays all zero's.

Pressing the "Origin" button displays 1.0000" and will display that at any thimble position when pressed. The display will then count from that point.

If your mic has an "Origin", "Set", or "Preset" button, play with that and see what you get as it may display .2000" when pressed, so you would set the micrometer to the setting ring and then press "Origin" to display .2000", and then it should count from that point.

I can't think of a third guess just yet as nearly all of my ID and OD micrometers are analog.

[Inspector]

On a Mit, if I remember correctly, to calibrate/set the hole test (inside mic) you put it into a ring gauge and expand the jaws with the ratchet. Press the Origin (sometimes it is Preset depending on the age of the tool) button and hold it until the display flashes and an underline appears under the numbers. You keep holding and the underline flashes a few times and moves to the next numeral. To change the value of that numeral you press the Origin once for each increase until you reach the value you want and hold the button down at that value. The underline will move on to the next numeral and you repeat until the last one is done, and then let go of the Origin button. You set the mic to the exact number etched on the ring gauge, 0.2003 for example. Now your value is set every time you pick up the tool to use. Before using I would always verify the readout was reading correctly with the ring gauge or better, one closest to the holes you want to measure. Something necessary when using tools others also used.

Pete

[JimGlass]

This post has been pretty well covered but thought I would offer some opinions on inside micrometers.
I bought a Mitutoyo electronic micrometer 6 years ago. I bought it for my old eyes and thought it may
reduce measuring errors. Very nice tool but large, heavy and clumsy to use. Works great ID measuring in the lathe but not when boring holes in the milling machine.

I also have Mitutoyo screw type ID micrometer I bought 40 years ago. Great tool, small, light weight and works well in the lathe or mill for measuring holes.

I bought another ID mic made in China and it has served me well also.