2A753 CDC vol 1 unit 1 Self Test
Questions & Answers
How can you tell when the V-belt on a drill press is adjusted properly? Correct Ans-When the
V-belt deflects approximately 1/2 inch.
Whether you are using a carbon steel or HS alloy steel twist drill, what must you avoid to ensure
satisfactory results? Correct Ans-Overheating the twist drill.
Why do you never cool and HS steel twist drill in water? Correct Ans-Because the metal may
crack.
Why are flutes necessary on a twist drill? Correct Ans-They allow the chips to escape, plus
they allow the lubricant to flow easily down to the lips.
What part of a twist drill does the actual cutting? Correct Ans-The lips
What is sometimes called the backbone of a twist drill? Correct Ans-The web
Why do you use a reamer? Correct Ans-To smooth and enlarge the holes to the exact size
needed.
, What physical property of reamers requires that they be handled carefully at all times?
Correct Ans-They are very brittle.
Why are bottom reamers used? Correct Ans-To complete the reaming of blind holes.
Which type of reamer is the most practical for general use? Correct Ans-Expansion reamer
Each increment on a stop countersink represents how many thousandths of an inch? Correct
Ans-0.001
How can you ensure countersunk holes have plenty of gripping surface? Correct Ans-
Countersink only material that is twice as thick as the countersunk portion of the rivet being
installed.
What factor determines whether fastener holes are countersunk or dimpled? Correct Ans-The
thickness of the material.
What are four causes of elongated holes when countersinking? Correct Ans-Any four of the
following:
(1) Tipping the countersink to one side.
(2) Creating oversized rivet holes or undersized countersink pilots
(3)Improperly using the countersink.
(4) Using a countersink in poor condition.
Questions & Answers
How can you tell when the V-belt on a drill press is adjusted properly? Correct Ans-When the
V-belt deflects approximately 1/2 inch.
Whether you are using a carbon steel or HS alloy steel twist drill, what must you avoid to ensure
satisfactory results? Correct Ans-Overheating the twist drill.
Why do you never cool and HS steel twist drill in water? Correct Ans-Because the metal may
crack.
Why are flutes necessary on a twist drill? Correct Ans-They allow the chips to escape, plus
they allow the lubricant to flow easily down to the lips.
What part of a twist drill does the actual cutting? Correct Ans-The lips
What is sometimes called the backbone of a twist drill? Correct Ans-The web
Why do you use a reamer? Correct Ans-To smooth and enlarge the holes to the exact size
needed.
, What physical property of reamers requires that they be handled carefully at all times?
Correct Ans-They are very brittle.
Why are bottom reamers used? Correct Ans-To complete the reaming of blind holes.
Which type of reamer is the most practical for general use? Correct Ans-Expansion reamer
Each increment on a stop countersink represents how many thousandths of an inch? Correct
Ans-0.001
How can you ensure countersunk holes have plenty of gripping surface? Correct Ans-
Countersink only material that is twice as thick as the countersunk portion of the rivet being
installed.
What factor determines whether fastener holes are countersunk or dimpled? Correct Ans-The
thickness of the material.
What are four causes of elongated holes when countersinking? Correct Ans-Any four of the
following:
(1) Tipping the countersink to one side.
(2) Creating oversized rivet holes or undersized countersink pilots
(3)Improperly using the countersink.
(4) Using a countersink in poor condition.
