🔍 Key Concepts

• Reading the sleeve (barrel) scale on an inch micrometer in 0.025 inch steps and identifying the last full graduation that is completely visible to the left of the thimble edge. • Using the thimble scale where each division usually equals 0.001 inch, and finding which thimble line lines up with the reference line on the sleeve. • Using the vernier scale on the sleeve to read to 0.0001 inch by finding which vernier line best lines up with a line on the thimble.

💭 Think About

• On figure D, what is the largest value you can confidently read from the sleeve alone, before you even look at the thimble or vernier? Is it just past the 0.500 mark or farther? • Which exact thimble graduation coincides with the horizontal reference line on the sleeve, and what thousandths of an inch does that represent? • After you have the sleeve reading plus the thimble reading, which single vernier line is in perfect alignment with a line on the thimble, and what ten‑thousandth value does that add?

✅ Before You Answer

• Be sure the sleeve reading you use is the last full 0.025 inch mark that is completely visible, not one that is partially covered by the thimble. • Confirm that the thimble line you choose is the one that lines up exactly with the sleeve’s reference line; do not estimate between lines. • After adding sleeve + thimble + vernier values, check that your final number matches one of the choices exactly, including the ten‑thousandths (0.0001) place.