Micrometer Screw Gauges manufacturers, suppliers,

The Micrometer Screw Gauge offered by Sai Scientific Instruments is a precision measuring tool designed for accurate measurement of small dimensions, such as the diameter of wires or the thickness of thin materials.

Parts of a Micrometer Screw Gauge

1. Frame

   • C-shaped body that holds the anvil and barrel in place.

2. Anvil

   • The fixed measuring surface against which the object is placed.

3. Spindle

   • Movable part that comes into contact with the object; moves as the thimble is rotated.

4. Sleeve (Barrel)

   • Stationary cylindrical part with a linear scale.

5. Thimble

   • Rotating part attached to the spindle; has a circular scale.

6. Ratchet Stop

   • Ensures uniform pressure while measuring.

7. Lock Nut

   • Used to lock the spindle in place after measurement.

📏 Working Principle

A micrometer works on the principle of a screw mechanism. When the thimble is rotated, the spindle moves forward or backward based on the pitch of the screw. Each full rotation of the thimble moves the spindle a set distance (typically 0.5 mm). Fine divisions on the thimble and sleeve allow measurements to a high degree of accuracy.

🧮 Least Count / Resolution

The least count of a micrometer is the smallest value it can measure, usually:

• Least Count = Pitch of Screw / Number of divisions on Thimble

• For a standard micrometer:
  Pitch = 0.5 mm, Thimble divisions = 50
  ⇒ Least Count = 0.5 mm / 50 = 0.01 mm

📚 How to Take a Reading

1. Place the object between the anvil and spindle.

2. Rotate the thimble until the object is gently held, using the ratchet for consistent pressure.

3. Read the main scale (sleeve) first (e.g., 5.5 mm).

4. Add the thimble reading (e.g., 28 × 0.01 = 0.28 mm).

5. Total = Main Scale + Thimble Scale = 5.5 + 0.28 = 5.78 mm

✅ Advantages

• High accuracy (up to 0.01 mm or 0.001 mm in digital versions)

• Easy to use with minimal training

• Durable and reliable for repeated use

❌ Limitations

• Can only measure small objects

• Limited measuring range (typically 0–25 mm)

• Requires careful handling to avoid parallax error or thread damage

🧪 Types of Micrometers

1. Outside Micrometer – for measuring external dimensions.

2. Inside Micrometer – for internal dimensions.

3. Depth Micrometer – for measuring depth of holes or recesses.

4. Digital Micrometer – displays readings digitally for ease and precision.