Main Parts of a Drilling Machine

1
Main Parts of a Drilling Machine
2
Drill Types and Holding Methods

• Parallel shank drills as the name suggests have a
  parallel shank and are held in the drilling
  machine using a three jaw self centring chuck.
• These types of drill range from 0.5mm to 13mm
  diameter in 0.5mm increments as standard.
• Sizes in between at 0.1mm increments are
  available for tapping dills and special
  applications but are more expensive.
• The chuck is fixed in to the spindle of the
  machine using a Morse taper.
• When fitting drills in to the chuck it is
  essential that the chuck only grips on the shank
  of the drill and the correct chuck key is used

3
Drill Types and Holding Methods

• Drills larger than 13mm diameter are manufactured
  with a taper shank as seen opposite.
• These types of drills are fitted directly in to
  the spindle of the drilling machine as opposed to
  in a chuck.
• The drill is held in place by means of friction
  between the taper on the shank and the taper in
  the spindle.
• This means much larger drills can be used without
  the risk of them slipping due to the larger area
  in contact with the machine.
• The tang on the top is purely to remove the drill
  from the machine not to secure it in place.

4
Morse Taper Sleeves and Adaptors

• Taper shank drills are available as standard in
  0.5 mm increments up to around 50mm diameter.
• The tapered shank (Morse Taper) on the drill is
  available in a range of sizes depending on drill
  size these being MT1, MT2, MT3 and MT4.
• The Taper in the spindle of drilling machines
  also varies depending on the size of the machine
  usually MT2, MT3, MT4 or MT5.
• To enable fitting of different size drills in
  different machines Morse Taper Sleeves and
  Adaptors are available, these come in various
  sizes e.g. MT1-MT2, MT2-MT3 etc. Allowing you
  to step up or down depending on the spindle size
  and the drill being used.

5
Fitting Taper Shank Drills or Chucks

• To fit the chuck or taper shank drill in to the
  machine the taper is inserted into the spindle
  with the tang rotated to line up with the slot as
  shown opposite.
• The drill is then secured into the spindle using
  one of the following methods.
• Tapping the drill into the spindle lightly using
  a soft faced mallet
• Placing a piece of wood on the table and rotating
  the spindle handle until the drill lowers and
  touches the wood then applying light pressure to
  push the drill securely into place.
• In both cases only minimal force is required as
  the power is transmitted by friction between the
  two tapered components.

6
Removing Taper Shank Drills or Chuck

• To remove the taper shank drill or chuck, the
  spindle is rotated by hand until the slot lines
  up with the slot on side casing.
• A drill drift is then inserted into the slot and
  tapped with a hammer as shown.
• This ejects the drill from the machine and the
  drill drift can then be removed.
• When ejecting the drill or chuck from the machine
  it is essential to hold it at the same time to
  prevent it falling on the floor which can cause
  damage.

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Main parts of the Drill
8
Drill Point Angle

• It is important that the angle point and the
  length of the of the cutting edges (lips) are
  ground accurately and equally to avoid problems
  when drilling holes.
• This can be checked when sharpening using a drill
  angle gauge as shown opposite
• If the angles are different it can cause the
  drill to chatter and drill a hole that is out of
  shape, a bit like a 50p piece.
• If the edges are of different lengths it can
  cause hole to be drilled over size as shown.

9
Drilling Holes

• When drilling holes it is essential the location
  is accurate, to achieve this we start the hole
  using a centre drill. Due to its small point the
  centre drill can be located accurately in the
  centre punch mark also it provides a good lead
  for the correct size drill
•  When drilling larger holes it is necessary to
  use a pilot drill to remove some of the material
  first. Trying to take too much material out at
  once will make the process more difficult, and
  may cause damage due to overheating of the drill
  and material

10
Countersinks and Counter Bores

• When several items are to be assembled together
  Countersink screws or cap head screws, are often
  used and these need to sit down flush with the
  component.
• To achieve this we use countersinks bits top
  right or counter boring drills bottom right.
• When counter boring you need to ensure that the
  pilot hole is the correct size for the shank of
  the tool.
• When using these tools it is essential that the
  speed of the drill is slowed down or the tool
  will overheat and become blunt very quickly.

11
Reamers and their use

• Drilling holes is reasonably accurate but some
  holes need to be perfect or have a much better
  surface finish than that achieved by drilling.
• To achieve this a Reamer is used.
• Reamers are of similar shape to drills but have
  more flutes and no point, they also run slower,
  around a third of the speed of drills.
• Reamers come with either a spiral flute or a
  straight flute as shown, they also come in hand
  version or machine versions

• Hand Reamer Machine Reamer

12
Use of Machine and Hand Reamers

• Machine reamers are used in the same way as
  drills by inserting them in a drilling machine as
  shown
• Hand reamers are used by placing them in a tap
  wrench as shown and rotating them by hand
• When reaming a hole you need to drill a pilot
  hole roughly half a millimetre smaller than the
  finished size and then open it up using the
  reamer.

• Using a Machine Reamer

• Using a Hand Reamer