Starrett 749.1 - Examples: Graduated in Thousandths of an Inch (.001)

749.1 User Guide 9 Ver 1.0
The L. S. Starrett Company 6/8/2023
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3.1 Examples: Graduated in Thousandths of an Inch (.001")
• The Depth Micrometer scale reads from right to left. The measurement is made by comparing what you can see with what you
cannot.
• Most of the time the thimble edge will be obscuring the hundred thousandths (.100'') line number.
Example 1
1. Fig.13A, If the 8 (.800”) line is showing and the 7 (.700”) line is not then the measurement is greater then >.700”.
2. Fig.13B, Which of the smaller thousandths (.025”) lines are showing on the sleeve below the 8 line? If the .775”, .750”
and .725” lines are showing then the measurement is greater then >.700” but less then <.725”.
3. Where the reading line on the sleeve coincides with a line on the thimble, this is how much the measurement is greater then
>.700”.
4. Fig.13B, the line on the thimble reads “24” (.024”). The measurement is; .700” + .024” = .724”
Example 2
1. Fig.14, Line "8" on the sleeve is visible, but Line "7" is not so the measurement is greater than >.700".
2. There is no .775” line showing so the measurement is greater than > .775”.
3. The thimble reads 5 so the measurement is greater than >.775” by +.005”.
4. The measurement is; .775” + .005” = .780”.
Thimble Sleeve
Thimble
Sleeve
Reading Line
.024”
.775”
.750”
.725”
.800”
.700”
.005”
Sleeve + Thimble = Measurement
.700”
.800”
Fig.13A
Fig.13B
Fig.14