CHAPTER 3 - DRILLING HOLES IN MATERIALS Flashcards

1
Q

PREPARATION AND MARKING OUT
What does the helical fluting provide on a drill?

A

Provides the cutting edges of the drill with a rake angle
Assists in clearing waste material (swarf) and a path down for lubricant to follow.

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2
Q

PREPARATION AND MARKING OUT
Which is the most efficient drill used in metalwork?
Why?

A

Twist Drill because of the helical fluting

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3
Q

PREPARATION AND MARKING OUT
What do the initials HSS mean?
What do the initials CS mean?

A

High Speed Steel
Carbon Steel

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4
Q

PREPARATION AND MARKING OUT
What are the advantages of a HSS drill?

A

HSS drills are made from alloy steel and can cut at much inherent speeds without sustaining damage to their cutting edges

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5
Q

PREPARATION AND MARKING OUT
If a drill is too small to have its size written on its shank, what can be used to check its size?

A

By using a drill gauge

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6
Q

PREPARATION AND MARKING OUT
What type of shank does a drill under 12.5mm have?

A

Usually has a parallel shank and carried in the chuck of the drilling machine

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7
Q

PREPARATION AND MARKING OUT
What is the maximum size of drill that can be fitted to a pistol drill chuck?

A

12.4mm

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8
Q

PREPARATION AND MARKING OUT
Name the two grades of twist drill in common use?

A
  1. Carbon Steel
  2. High Speed Steel
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9
Q

PREPARATION AND MARKING OUT
Which type of lubricant is used on mild steel?

A

Soluble oil

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10
Q

PREPARATION AND MARKING OUT
Name 3 properties of a lubricant…

A

-Improve the quality of the hole
-Assists In dissipating the heat produced from the drill
-Improves the cutting efficiency
-Prolongs the life of the drill

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11
Q

PREPARATION AND MARKING OUT
Which type of lubricant is used on Aluminium?

A

Kerosene

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12
Q

PREPARATION AND MARKING OUT
Before drilling, what must you ensure?

A

-Item is supported by a suitable piece of scrap material to avoid drilling into the machine table or the body of the drill vice

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13
Q

PREPARATION AND MARKING OUT
What 3 situations could happen if the work isn’t properly supported before drilling starts?

A

-Broken drills
-Damaged work
-Personal Injury

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14
Q

PREPARATION AND MARKING OUT
Why do we centre punch before drilling?

A

In order to position the drill

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15
Q

PREPARATION AND MARKING OUT
What 2 things must the centre-punch mark be?

A
  1. Accurate in position
  2. Large enough to take the chisel edge of the drill
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16
Q

DRILLING PROCEDURE
When drilling deep holes, what must you do frequently?

A

Lift the drill from the hole at frequent intervals, stop the machine and use a brush to sweep the swarf from around the hole

17
Q

PREPARATION AND MARKING OUT
Why do we Pilot Drill?

A

-Large drills have a large chisel edge, so centre-punch marks of the proportional amount could not be positioned accurately enough
-The above scenario also means a greater pressure being applied. This is relieved by a pilot hole
-Permit small tolerances before drilling holes to their final dimensions

18
Q

DRILLING PROCEDURE
When drilling is complete, what should you continue to do when removing the drill?

A

Keep the drill turning clockwise as it is withdrawn

19
Q

COUNTERSINKING
What is a countersinking tool used for?

A

Used to cut a seating around a drilled hole for flush-fitting countersink screws, bolts or rivets

20
Q

REAMERS
What are reamers used for?

A

Reamers are precision-ground cutting tool. They are used to enlarge drilled holes to accurate dimensions and give a good smooth finish

21
Q

REAMERS
What is a tapered reamer used for?

A

Type of reamer is used to produce, from a normally drilled hole, a tapered hole suitable for the fitting of taper pins.

22
Q

REAMERS
How would you check the size of a hand expanding reamer?

A

Checked by a ring-type gauge of the required size or by using an outside micrometer calliper

23
Q

REAMERS
How would you check the size range of a hand expanding reamer?

A

Stamped on its shank

24
Q

REAMERS
On an imperial reamer, what does fractional number mean?

A

Shows the taper between the reamer and its taper pins

25
Q

REAMERS
Name the three types of machine reamers…

A
  1. Hand and Machine Parallel
  2. Hand Expanding
  3. Hand Taper
26
Q

REAMERS
What size is the metric reamer taper?

A

1 in 50

27
Q

INTERNAL THREADS
Name the 3 taps in common use…

A
  1. Taper Tap
  2. Secondary (intermediate) Tap
  3. Plug (Bottoming) Tap
28
Q

INTERNAL THREADS
Which tap is used to start cutting an internal thread?

A

Taper Tap