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Zorluk: ZorPrecision Measurement Instruments

A technician is using a 2–3 inch2\text{--}3\text{ inch} vernier outside micrometer to measure the diameter of a crankshaft main journal. The sleeve reveals the major graduation mark 77 and two additional 0.025-inch0.025\text{-inch} subdivision marks past the 77. The thimble graduation aligned with the sleeve index line indicates 1919, and the vernier scale on the sleeve aligns with a thimble mark at the 44 line. What is the final measured diameter of the crankshaft journal?

  1. A
    2.7444 inches2.7444\text{ inches}
  2. 2.7694 inches2.7694\text{ inches}Cevap
  3. C
    2.7194 inches2.7194\text{ inches}
  4. D
    2.7944 inches2.7944\text{ inches}

Cevap

2.7694 inches2.7694\text{ inches}
The correct diameter is 2.7694 inches2.7694\text{ inches}. On a 2–3 inch2\text{--}3\text{ inch} micrometer, the measurement starts at 2.000 inches2.000\text{ inches}. The major mark 77 on the sleeve contributes 0.700 inch0.700\text{ inch}, the two visible 0.025-inch0.025\text{-inch} subdivisions add 0.050 inch0.050\text{ inch}, the thimble line 1919 adds 0.019 inch0.019\text{ inch}, and the aligned vernier mark 44 adds 0.0004 inch0.0004\text{ inch}. Summing these values gives 2.000+0.700+0.050+0.019+0.0004=2.7694 inches2.000 + 0.700 + 0.050 + 0.019 + 0.0004 = 2.7694\text{ inches}.

Adım Adım Çözüm

1
Identify the base dimension from the micrometer frame size
Base size =2.000 in= 2.000\text{ in}
A 2–3 inch2\text{--}3\text{ inch} micrometer starts measuring at a baseline of 2.000 inches2.000\text{ inches} when fully closed.
2
Read the major sleeve markings and minor subdivision lines
Sleeve reading =0.700 in+(2×0.025 in)=0.750 in= 0.700\text{ in} + (2 \times 0.025\text{ in}) = 0.750\text{ in}
Each numbered line on the sleeve represents 0.100 inch0.100\text{ inch}, and each subdivision line between numbers represents 0.025 inch0.025\text{ inch}.
3
Read the thimble scale graduation aligned with the sleeve index line
Thimble reading =19×0.001 in=0.019 in= 19 \times 0.001\text{ in} = 0.019\text{ in}
Each graduation around the circumference of the thimble represents one-thousandth of an inch (0.001 in0.001\text{ in}).
4
Read the vernier scale on the sleeve for ten-thousandths resolution
Vernier reading =4×0.0001 in=0.0004 in= 4 \times 0.0001\text{ in} = 0.0004\text{ in}
The matching vernier line on the sleeve adds ten-thousandths of an inch (0.0001 in0.0001\text{ in}) precision.
5
Calculate the total measured diameter
2.000 in+0.700 in+0.050 in+0.019 in+0.0004 in=2.7694 in2.000\text{ in} + 0.700\text{ in} + 0.050\text{ in} + 0.019\text{ in} + 0.0004\text{ in} = 2.7694\text{ in}
Adding all scale components together provides the final precision measurement.

Anahtar Kavram

Precision scale reading using a vernier outside micrometer with sleeve, thimble, and ten-thousandths vernier graduations.
Tahmini Süre:1m 30s
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