Micrometers, Gauge Blocks, and Dial Indicators (Week 3)

Question 1

What is a Micrometer?

Answer 1

Instrument for making precise linear measurements of dimensions such as diameters, thicknesses, and lengths of solid bodies.

Question 2

What should you do before using any measuring instrument?

Answer 2

Before using any measuring instrument, you must check to ensure it is calibrated (accurate).

Question 3

What is the Vernier Scale of a Micrometer?

Answer 3

The Vernier scale allows you to refine your measurement even further down to just 0.0001”

Question 4

What are Gauge Blocks and what is their purpose?

Answer 4

• Gauge blocks are a necessity in any testing environment that requires linear dimensional accuracy and calibration of measuring tools such as micrometers and calipers.
• Each block is engraved with an individual serial number and the size of the gauge for calibration purposes.
• The purpose of gauge blocks is to provide linear dimensions known within a given tolerance.

Question 5

How do you care for Gauge Blocks?

Answer 5

• Keep in closed case to protect from dust and dirt. Do not drop or scratch their lapped surfaces.
• Immediately after use, each block should be cleaned, oiled, and replaced in the storage case.

Question 6

List the steps used to wring Gauge Blocks together.

Answer 6

• Clean blocks with clean, soft cloth
• Wipe each contacting surface on clean hand palm or on wrist
• Place end of one block over end of another block
• While applying pressure, slide one block over other

Join (two smooth flat surfaces, slip gauges) by hand pressure and a slight twisting movement

Question 7

What are Dial Indicators used for?

Answer 7

Used to compare sizes and measurements to a known standard and check the alignment of machine tools, fixtures, and workpieces before machining.

Question 8

What are two types of Dial Indicators?

Answer 8

1. Continuous-reading dial indicator
2. Dial test indicator

Question 9

Properties of a Continuous-reading dial indicator?

Answer 9

• Numbered clockwise for 360º
• Regular-range
  – Only 2 ½ revolutions
• The dial indicator consists of a plunger that can move up or down moving the dial hand in either a clockwise or counter-clockwise Direction.

Question 10

Properties of a Dial test indicator?

Answer 10

• Reads both right and left from 0
• Equipped with tolerance pointers