Vít micromet – các vấn đề và giải pháp
1. Việc đo đường kính của dây bằng... thước trắc vi là 2.48mm. Hình ảnh tương ứng với kết quả đo là…
Giải pháp:
A. Wire diameter = 4, …..
B. Wire diameter = 3, …..
C. Wire diameter = 2, …..
D. Diameter of wire = 1, …..
E. Wire diameter = 4, …..
Câu trả lời đúng là c.
2. The measurement of the diameter of the wire with a micrometer is 1.95 mm. The image that matches with the measurement results is…
Giải pháp:
A.
Main scale = 1.5 mm
Swivel scale = 38 x 0.01 mm = 0.38 mm
0.01 mm is the threshold of micrometer screws accuracy.
Wire diameter = 1.5 mm + 0.38 mm = 1.88 mm.
B.
Main scale = 1.5 mm
Swivel scale = 39 x 0.01 mm = 0.39 mm
0.01 mm is the threshold of micrometer screws accuracy
Wire diameter = 1.5 mm + 0.39 mm = 1.89 mm
C.
Main scale = 1.5 mm
Swivel scale = 43 x 0.01 mm = 0.43 mm
0.01 mm is the threshold of micrometer screws accuracy
Wire diameter = 1.5 mm + 0.43 mm = 1.93 mm
D.
Main scale = 1.5 mm
Swivel scale = 42 x 0.01 mm = 0.42 mm
0.01 mm is the threshold of micrometer screws accuracy
Wire diameter = 1.5 mm + 0.42 mm = 1.92 mm
E.
Main scale = 1.5 mm
Swivel scale = 45 x 0.01 mm = 0.45 mm
0.01 mm is the threshold of micrometer screws accuracy
Wire diameter = 1.5 mm + 0.45 mm = 1.95 mm
Câu trả lời đúng là E.
3. The result of the measurement of the diameter of the metal granule sphere by using screw micrometer is 2.75 mm. The image that matches with the measurement results is…
Giải pháp:
A.
Main scale = 2.5 mm
Swivel scale = 20 x 0.01 mm = 0.20 mm
Wire diameter = 2.5 mm + 0.20 mm = 2.7 mm
B.
Main scale = 2.5 mm
Swivel scale = 15 x 0.01 mm = 0.15 mm
Wire diameter = 2.5 mm + 0.15 mm = 2.65 mm
C.
Main scale = 2.5 mm
Swivel scale = 25 x 0.01 mm = 0.25 mm
Wire diameter = 2.5 mm + 0.25 mm = 2.75 mm
Câu trả lời đúng là c.
4. The measurement of the diameter of the steel cylinder with a screw micrometer is 4.47 mm. The correct measurement result shown in the following figure is…
Giải pháp:
A.
Main scale = 4.5 mm
Swivel scale = 47 x 0.01 mm = 0.47 mm
0.01 mm is the threshold of micrometer screws accuracy
Wire diameter = 4.5 mm + 0.47 mm = 4.97 mm
B.
Main scale = 4 mm
Swivel scale = 47 x 0.01 mm = 0.47 mm
0.01 mm is the threshold of micrometer screws accuracy
Wire diameter = 4 mm + 0.47 mm = 4.47 mm
C.
Main scale = 5.5 mm
Swivel scale = 47 x 0.01 mm = 0.47 mm
0.01 mm is the threshold of micrometer screws accuracy
Wire diameter = 5.5 mm + 0.47 mm = 5.97 mm
D.
Main scale = 3 mm
Swivel scale = 47 x 0.01 mm = 0.47 mm
0.01 mm is the threshold of micrometer screws accuracy
Wire diameter = 3 mm + 0.47 mm = 3.47 mm
E.
Main scale = 7.5 mm
Swivel scale = 47 x 0.01 mm = 0.47 mm
0.01 mm is the threshold of micrometer screws accuracy
Wire diameter = 7.5 mm + 0.47 mm = 7.97 mm
1 câu hỏi: What is the primary purpose of a micrometer screw?
Câu trả lời: The primary purpose of a micrometer screw is to measure small dimensions with high precision, typically to the nearest hundredth of a millimeter or thousandth of an inch.
2 câu hỏi: How does a micrometer achieve its precision?
Câu trả lời: A micrometer achieves its precision through a finely threaded screw mechanism. One complete turn of the thimble advances or retracts the spindle by a known small distance.
3 câu hỏi: What is the ‘pitch’ of the micrometer screw?
Câu trả lời: The pitch is the linear distance the spindle moves for one complete rotation of the screw.
4 câu hỏi: Why do micrometers have a ratchet mechanism?
Câu trả lời: The ratchet mechanism ensures consistent force when tightening the micrometer, preventing over-tightening and potential damage to the object being measured or the micrometer itself.
5 câu hỏi: How is the reading on a micrometer taken?
Câu trả lời: The reading is taken by combining the linear measurement indicated on the sleeve with the rotational measurement from the thimble scale.
6 câu hỏi: Why is the frame of a micrometer often ‘C’ shaped?
Câu trả lời: The ‘C’ shape provides strength and rigidity to the instrument while allowing easy access for placing and removing the object being measured.
7 câu hỏi: What are the anvil and spindle in the context of a micrometer?
Câu trả lời: The anvil is the stationary part against which the object is placed, and the spindle is the moving part that contacts the other side of the object being measured.
8 câu hỏi: What precaution should be taken when storing a micrometer?
Câu trả lời: A micrometer should be stored with the spindle slightly away from the anvil, preventing the pressure of constant contact and potential deformation. Also, storing it in a protective case prevents dust accumulation and physical damage.
9 câu hỏi: Why is it important not to drop a micrometer?
Câu trả lời: Dropping can damage the precision surfaces of the anvil and spindle, compromise the alignment, and adversely affect its accuracy.
10 câu hỏi: How does temperature affect micrometer measurements?
Câu trả lời: Metals expand with an increase in temperature. Since micrometers are often made of metal, temperature changes can affect their dimensions and, thus, the accuracy of measurements.
11 câu hỏi: What is the function of the lock on some micrometers?
Câu trả lời: The lock, or locking mechanism, secures the spindle in place after a measurement is taken, ensuring it doesn’t move while reading the measurement.
12 câu hỏi: Why do some micrometers have a carbide-tipped anvil and spindle?
Câu trả lời: Carbide tips are harder and more wear-resistant than plain steel, ensuring longer life and consistent accuracy of measurements.
13 câu hỏi: What is the difference between a micrometer and a caliper?
Câu trả lời: While both are measuring tools, a micrometer measures using a screw mechanism and is generally more precise. In contrast, a caliper uses a slide mechanism and can measure internal, external, and depth dimensions.
14 câu hỏi: How is zero error accounted for in a micrometer?
Câu trả lời: Zero error is checked by closing the micrometer without any object between the anvil and spindle. Any discrepancy from zero is noted and adjusted for in subsequent measurements.
15 câu hỏi: Why should one avoid rotating the thimble rapidly?
Câu trả lời: Rapid rotation can damage the threads of the micrometer screw, affecting its accuracy.
16 câu hỏi: Why are digital micrometers considered advantageous by some users?
Câu trả lời: Digital micrometers provide direct digital readings, eliminating potential reading errors from the analog scale, and can be quicker and more intuitive for some users.
17 câu hỏi: What is the function of the scale on the sleeve of the micrometer?
Câu trả lời: The scale on the sleeve indicates whole millimeters or tenths of inches (depending on the unit) and provides the main linear measurement.
18 câu hỏi: Why is the thimble typically divided into 50 or 100 divisions?
Câu trả lời: This division corresponds to the pitch of the screw. For a 0.5 mm pitch, each division on the thimble represents 0.01 mm. For a 0.025-inch pitch, each division would indicate 0.0005 inches.
19 câu hỏi: How can a user measure the depth using a micrometer?
Câu trả lời: Depth measurements typically require a depth micrometer, which has a rod extending from the base for depth measurement, as opposed to the typical outside micrometer.
20 câu hỏi: What’s the significance of having a friction thimble on some micrometers?
Câu trả lời: A friction thimble ensures that a consistent force is applied when taking measurements, leading to more consistent and accurate readings.
Understanding the intricacies of the micrometer screw is vital for those in precision engineering and related fields where accurate measurements are essential.
