A little embarrassed, can't read this outside mic....

[SLK001]

What you have is a mic that has a resolution of 0.001". The mics with the "lines" have a resolution of 0.0001". Your first photo shows 0.025", which is the resolution of the mic. With experienced readers, the extra digit of resolution can be guestimated to a very find detail, thus the 0.0253" reading.

 

[Mill Lee farm]

Ok… as one who is learning as well, I thought I’d try putting some numbers on the photo.
Let me know if I messed up!



I did look closer and feel the tenths interpolation is closer to .0006-.0007. NOT .0008?
(Edit: changed pic to reflect .0007 [.1527] instead of .0008 [.1528]. Also edited photo to .1527 instead of original incorrect.1258)

I’m also assuming that Dave’s answer of .0005 is an accuracy rounding?
Choose either .1520, .1525 or .1530?
Or is it acceptable to attempt to interpolate to individual tenths? (.0001 through .0009?)

————————————————————
Edit: I will also add that this micrometer is only accurate to .001. The proper reading is therefore actually .152”. (That’s .150” on the main stationary barrel + the .002” on the moving barrel)
The tenth’s ‘interpolation’ that I was talking about is guesswork. As previously stated there is no tenth’s (.0001”) resolution or vernier on this micrometer.

I add this because I think the original confusion might be related to the lack of the tenth’s (.0001”) vernier scale on this micrometer.

I dove down to the tenths rabbit hole (yellow circle/line) which is guesswork based on the position of the line between the two actual known marks (.002” and .003”)

 

[woodchucker]

those numbers in yellow are incorrect. the first is correct, the second you probably meant .1528

 

[Mill Lee farm]

those numbers in yellow are incorrect. the first is correct, the second you probably meant .1528

Doh!!! Sure enough… yes, that’s totally wrong and was supposed to be .1526 - .1528 (.1527 after looking again)

Sorry. Putting the numbers in was a bit if a pita.
I’ll see if I can fix it.

 

[RJSakowski]

Resolution on a digital instrument is limited by the least significant digit. A digital caliper that reads to .001 can't resolve any finer than that. A reading of .253 means the value is greater than .2525 but less than .2535. Using a set of gage pins to determine the diameter of a hole is limited to the resolution of the gage pin set. If the set increments by .001, it isn't possible to resolve any better than .001".

However analog instruments can be interpolated to give better resolution than the scale markings. An example is a dial test indicator. An indicator with .0005" markings can tell you if your TIR is actually .0002". Another example is the dial on a lathe cross feed. The marks are .001" aprt but one can easily turn a diameter to .0001" tolerance. If one limits their micrometer measurements to the markings on the thimble, they are limiting their capability to do precision work.

 

[RJSakowski]

Doh!!! Sure enough… yes, that’s totally wrong and was supposed to be .1526 - .1528 (.1527 after looking again)

Sorry. Putting the numbers in was a bit if a pita.
I’ll see if I can fix it.

No need to change the photo. Just edit your post the state that the number is incorrect and what the correct value should be.

 

[great white]

Ok… as one who is learning as well, I thought I’d try putting some numbers on the photo.
Let me know if I messed up!

View attachment 453077

I did look closer and feel the tenths interpolation is closer to .0006-.0007. NOT .0008?

I’m also assuming that Dave’s answer of .0005 is an accuracy rounding?
Choose either .1520, .1525 or .1530?
Or is it acceptable to attempt to interpolate to individual tenths? (.0001 through .0009?)

Lol! That just confused me all over again….time for bed and a good nights sleep. Then back at it.

 

[mmcmdl]

My tolerance is +or- half of one of these . And damn , after looking at the price , I'm better off with dial verniers .

Hickory Handle Floor Brooms

Hickory is the strongest wood we use. The density of hickory makes them a bit heavier than other handles, but the straightness of the wood makes them easy to use. Each handle is slightly different. We will pick out our favorites for you, but if you wish to see photos of some of the exact stock...

broomcompany.com

 

[Mill Lee farm]

Lol! That just confused me all over again….time for bed and a good nights sleep. Then back at it.

Hey, let’s keep trying!
We all fail if we don’t get this figured out!

Seriously, it took me a lot of different youtube, internet and book explanations until I started to get my head around it. Even then, practice is key. I would gain understanding but then forget it a week later *sigh*…

I read this post as *practice* and failed at first!
My problem seems to come from a lifelong use of fractional rulers.
Compounding this problem is the fact that I DID get used to the “tenths of an inch” 6 inch rule/scale.

It’s hard to get my head around base .025” place-marks/slashes! I keep defaulting to base .010” and thinking that’s what the markers represent.

 

[RJSakowski]

This may help in visualizing what interpolating between the marks looks like. Here is a graphical representation of the positions for tenths of a division. from 1/10th to 9/10ths.