DIAL INSTRUMENTS

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• Q1: What are Dial Instruments?
  Ans: Dial instruments are precision measuring instruments that show readings on a circular dial with a pointer instead of a digital display.
• Q2: Name some Dial Instruments.
  Ans: Some dial instruments are:

  • ➔ Dial Caliper
  • ➔ Dial Thickness Gauge
  • ➔ Dial Bore Gauge
  • ➔ Dial Indicator
• Q3: What is a Dial Caliper?
  Ans: A dial caliper is a precision measuring instrument used to measure internal, external, and depth dimensions with a dial indicator.
• Q4: What is the working principle of a Dial Caliper?
  Ans: It works on the rack and pinion mechanism.
  The linear motion of the slider is converted into rotary motion of the dial pointer.
  The pointer shows the measurement on the dial.
• Q5: What is the Least Count of a Dial Caliper?
  Ans: The least count of a dial caliper is usually 0.02 mm.
• Q6: What is the size of a Dial Caliper?
  Ans: Dial calipers are commonly available in sizes like:

  • ➔ 150 mm
  • ➔ 200 mm
  • ➔ 300 mm
• Q7: Name the parts of a Dial Caliper.
  Ans: Parts are:

  • ➔ Main scale
  • ➔ Sliding jaw
  • ➔ Fixed jaw
  • ➔ Dial indicator
  • ➔ Depth rod
• Q8: State the uses of a Dial Caliper.
  Ans: Uses are:

  • ➔ Measuring external dimensions
  • ➔ Measuring internal dimensions
  • ➔ Measuring depth
  • ➔ Quick inspection work
• Q9: State the precautionary measure while using a Dial Caliper.
  Ans: Precautions are:

  • ➔ Handle carefully to avoid damage
  • ➔ Do not apply excessive force
  • ➔ Keep clean and dry
  • ➔ Check zero error before use
• Q10: How do you read a Dial Caliper?
  Ans: Read the main scale first.
  Then note the dial reading.
  Add both readings to get the final measurement.
• Q11: What is a Dial Thickness Gauge?
  Ans: A dial thickness gauge is a measuring instrument used to measure the thickness of thin materials using a dial indicator.
• Q12: What is the working principle of a Dial Thickness Gauge?
  Ans: It works on the spring-loaded mechanism.
  The movement of the contact point is converted into dial movement.
  The reading is shown on the dial.
• Q13: What is the Least Count of a Dial Thickness Gauge?
  Ans: The least count is usually 0.01 mm to 0.02 mm.
• Q14: What is the size of a Dial Thickness Gauge?
  Ans: Dial thickness gauges are available in different ranges such as:

  • ➔ 0–10 mm
  • ➔ 0–25 mm
• Q15: Name the parts of a Dial Thickness Gauge.
  Ans: Parts are:

  • ➔ Anvil
  • ➔ Spindle
  • ➔ Dial indicator
  • ➔ Frame
  • ➔ Spring mechanism
• Q16: State the uses of a Dial Thickness Gauge.
  Ans: Uses are:

  • ➔ Measuring sheet thickness
  • ➔ Checking rubber and plastic sheets
  • ➔ Quality inspection
• Q17: State the precautionary measure while using a Dial Thickness Gauge.
  Ans: Precautions are:

  • ➔ Do not apply extra pressure
  • ➔ Keep measuring faces clean
  • ➔ Handle gently
• Q18: How do you read a Dial Thickness Gauge?
  Ans: Place the material between the anvils.
  The spindle moves and dial pointer shows reading.
  Direct reading is taken from the dial.
• Q19: What is a Dial Bore or Hole Gauge?
  Ans: A dial bore gauge is a precision instrument used to measure the internal diameter of holes.
• Q20: What is the working principle of a Dial Bore or Hole Gauge?
  Ans: It works on the comparative measurement principle.
  The contact points expand inside the bore.
  Movement is transferred to the dial indicator.
• Q21: What is the Least Count of a Dial Bore or Hole Gauge?
  Ans: The least count is usually 0.01 mm.
• Q22: What is the size of a Dial Bore or Hole Gauge?
  Ans: Dial bore gauges are available in ranges such as:

  • ➔ 10–30 mm
  • ➔ 30–50 mm
  • ➔ 50–160 mm
• Q23: Name the parts of a Dial Bore or Hole Gauge.
  Ans: Parts are:

  • ➔ Dial indicator
  • ➔ Measuring head
  • ➔ Contact points
  • ➔ Extension rods
  • ➔ Handle
• Q24: State the uses of a Dial Bore or Hole Gauge.
  Ans: Uses are:

  • ➔ Measuring internal diameter of holes
  • ➔ Checking cylinder bores
  • ➔ Inspection work
• Q25: State the precautionary measure while using a Dial Bore or Hole Gauge.
  Ans: Precautions are:

  • ➔ Set zero correctly before use
  • ➔ Handle carefully
  • ➔ Avoid damage to contact points
• Q26: How do you read a Dial Bore or Hole Gauge?
  Ans: Insert the gauge into the bore.
  Move it slightly to find maximum reading.
  Note the dial reading and compare with standard size.