7.3.9 Drilling Flashcards
What is the primary tool used for drilling in airframe structural work?
Portable drills (electric or pneumatic) are usually the most practical tool for use in airframe structural work.
What is the distinction between a drill and a drill bit?
The ‘Drill’ is the tool that applies power to rotate the ‘Drill Bit’, which does the actual cutting of the material.
What are the most common types of pneumatic drills?
The most common pneumatic drills are: Pistol Grip Drill, Straight Drill, Right-angle Drill, and 45° Angle Drill.
What is the most common type of electric drill used in workshops?
The most common type of electric drill is the ‘Drill Press’, also known as the Pedestal Drill, Pillar Drill, or Bench Drill.
Why must drill bits be carefully managed by aircraft engineers?
Drill bits can cause FOD (Foreign Object Damage) and must be retrieved and accounted for at the end of any shift.
What are the main types of drill bits classified for cutting metal?
The main types of drill bits are: Twist Drill, Countersink, Counter-bore, Flat Bottom Boring, and Speciality.
What is the shank of a drill?
The shank is the part designed to fit into the drilling machine (chuck) and can be a plain cylinder or tapered.
What is the purpose of the flutes on a drill bit?
Flutes allow for the removal of chips (swarf) produced at the cutting edge and enable cutting fluid to reach the cutting lips.
What does the point of a drill consist of?
The point consists of the Cutting Edge (lips), the flank, the face, the Web, and the Chisel Edge.
What is the purpose of a countersink tool?
A countersink tool is used to create a conical hole for a screw head to sit flush with the surface.
What is the function of a microstop countersink tool?
The microstop countersink tool controls the countersink depth and keeps the cutter perpendicular to the work surface.
What is spot facing?
Spot facing is the method used for cutting a flat area or seat for a bolt head or nut on a contoured surface.
What is the purpose of a reamer?
A reamer is used to finish a drilled hole to the exact size, producing a smooth finish when precision is required.
When is a reamer used?
A reamer is used when absolute precision is required for finishing a hole to the exact size.
What is the first step in using a reamer?
A hole is first drilled with a normal twist drill, slightly smaller than the finished hole.
What are the two main types of reamers?
Hand reamers and machine (chucking) reamers.
What materials are reamers typically made from?
Reamers are made of either carbon tool steel or high-speed steel (HSS).
How do the cutting blades of HSS reamers compare to carbon steel reamers?
The cutting blades of a high-speed steel reamer lose their sharpness quicker than those made of carbon steel.
What is the purpose of the grooves on straight reamers?
The grooves provide a way for chips to escape and a channel for lubricant to reach the cutting edge.
What should not be done when withdrawing a reamer?
Do not attempt to withdraw a reamer by turning it in the reverse direction, as chips can be forced into the surface.
What is the function of hand reamers?
Hand reamers are used primarily ‘in-situ’ on the aircraft if the engineering instructions call for it.
What is important to ensure when using a hand reamer?
It is important to keep the reamer perfectly straight during the cutting process.
What is the difference between tapered reamers and bevel type hand reamers?
Tapered reamers produce tapered holes, while bevel type hand reamers require careful alignment with the hole.
What is an adjustable hand reamer used for?
An adjustable hand reamer is used to smooth the bore walls of a drilled hole when precise sizing is necessary.
