# Reading a ruler help, 1.2 or 1.02

Discussion in 'General Electronics Discussion' started by computer-joe, Dec 24, 2017.

1. ### computer-joe

29
6
Oct 6, 2016
help! i need some ruler help,

Im making a project on photo shop. I had to measure a paper cover i own

it measures 1.something by 1.something

i need to put that in photoshop, but the problem is i don't know the correct reading.

Would it be 1.02 or 1.20

here is a picture of that

2. ### Cannonball

191
53
May 6, 2017
1.2 and 1.4

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3. ### Bluejets

4,608
977
Oct 5, 2014
Half way between 1 and 2 would be 1.5 so it follows that 2 units out would be 1.2 and 4 units out would be 1.4.
Merry Christmas

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4. ### kellys_eye

4,275
1,147
Jun 25, 2010

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5. ### hevans1944Hop - AC8NS

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Jun 21, 2012

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6. ### dorke

2,342
665
Jun 20, 2015
Well,
Since you asked,(it is quite obvious to most people),
here is a simple way to deal with these kind of linear scales:

Each CM(biggest bars) is divided into 10 equally spaced smaller bars with one medium sized one in the middle.
It should be interpreted like so:

Each small bar is 1/10 of a CM (0.1CM).
The mid bar is 0.5CM.

That would work for all types of linear scales.

People used to CM scales take that(decimal system 1/10) to be an obvious thing.
When they switch to Inches they have a problem understanding the power of 2 system(1/2,1/4 1/8,1/16 etc.)

Isn't it about time to throw away that ridiculous inch system ?
Who in the world still uses it ,(USA and...)?
Apart from the difficulty of switching ,why ?

Last edited: Dec 24, 2017
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7. ### Bluejets

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Oct 5, 2014
Ah yes, but, it's quicker to say "knock off an extra thou" than it is to say" knock off an extra zero point zero two five millimetres".

Edit: for the machinists out there ....

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8. ### hevans1944Hop - AC8NS

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Jun 21, 2012
Yeah, I have trouble even seeing those itsy bitsy teeny weeny marks on a steel scale that is marked off in 1/64" increments. And it seemingly gets worse when that inch scale is only divided into fifty linear increments instead of sixty-four. I usually keep a set of vernier calipers with a dial indicator or a digital readout handy to verify that I've read the scale correctly.