To read a
micrometer screw gauge, we need to consider two parts:
1.
Main scale reading (on the sleeve) – This is the reading from the fixed scale.
2.
Thimble scale reading (on the rotating barrel) – This is the reading from the rotating part, which gives the fractional part.
The total reading is:
>
Total Reading = Main Scale Reading + Thimble Scale Reading
We assume that:
- The main scale is in
millimeters.
- Each division on the thimble represents
0.01 mm (since most micrometers have 50 divisions per rotation and 1 mm per full turn).
- The thimble scale is marked from 0 to 50, so each division = 0.01 mm.
Let’s go through each one step by step.
---
(a)
-
Main scale: The edge of the thimble is between 6 and 7 mm. But it has passed 6 mm and not reached 7 mm.
- The last visible mark before the thimble is at
6 mm.
- So,
Main Scale Reading = 6.0 mm
-
Thimble scale: The line on the thimble aligns with
9 on the thimble scale.
- Since each division = 0.01 mm → 9 × 0.01 =
0.09 mm
-
Total Reading = 6.0 + 0.09 = 6.09 mm
✔ Answer: 6.09 mm
---
(b)
-
Main scale: The thimble has passed 6 mm but not 7 mm →
Main Scale = 6.0 mm
-
Thimble scale: The line aligns with
38 on the thimble.
- 38 × 0.01 =
0.38 mm
-
Total Reading = 6.0 + 0.38 = 6.38 mm
✔ Answer: 6.38 mm
---
(c)
-
Main scale: The thimble has passed 6 mm →
Main Scale = 6.0 mm
-
Thimble scale: The line aligns with
34 (between 30 and 35)
- 34 × 0.01 =
0.34 mm
-
Total Reading = 6.0 + 0.34 = 6.34 mm
✔ Answer: 6.34 mm
---
(d)
-
Main scale: The thimble has passed 6 mm →
Main Scale = 6.0 mm
-
Thimble scale: The line aligns with
43 (just below 45)
- 43 × 0.01 =
0.43 mm
-
Total Reading = 6.0 + 0.43 = 6.43 mm
✔ Answer: 6.43 mm
---
(e)
-
Main scale: The thimble has passed 6 mm →
Main Scale = 6.0 mm
-
Thimble scale: The line aligns with
23 (between 20 and 25)
- 23 × 0.01 =
0.23 mm
-
Total Reading = 6.0 + 0.23 = 6.23 mm
✔ Answer: 6.23 mm
---
✔ Final Answers:
(a)
6.09 mm
(b)
6.38 mm
(c)
6.34 mm
(d)
6.43 mm
(e)
6.23 mm
Let me know if you'd like a visual explanation or want to understand how the scales work!
Parent Tip: Review the logic above to help your child master the concept of micrometer reading worksheet.
