DRILLING Flashcards
What is drilling?
Producing a cylindrical hole using a rotating tool called a drill.
How is the center of the hole located before drilling?
By drawing two perpendicular lines and using a center punch for indentation.
Does drilling produce an accurate hole?
No, drilling alone does not give a perfectly accurate or well-located hole.
What is reaming?
Sizing and finishing a pre-drilled hole to an accurate dimension.
Why is the hole drilled undersize before reaming?
To allow the reamer to remove a small amount of material and finish the hole.
Can a reamer create a new hole?
No, it follows the existing hole and cannot correct location.
What tool is used in reaming?
A reamer with multiple cutting edges.
Why use lubricant in reaming?
To prolong tool life and ensure a smoother finish.
What is boring?
Enlarging an existing hole using a boring tool.
When is boring used?
When the required drill size is unavailable or the hole is too large.
What is the speed of boring compared to reaming?
Slower than reaming.
Can boring correct hole location?
Yes, it can correct misaligned holes.
What is counterboring?
Enlarging one end of a drilled hole to create a square shoulder.
Why is counterboring done?
To accommodate bolt heads, studs, or pins.
What tool is used in counterboring?
Counter-bore tool with bottom and peripheral cutting edges and a pilot.
What speed is used in counterboring?
About 2/3rd the drilling speed for the same hole.
What is countersinking?
Making a cone-shaped enlargement at the end of a hole.
What tool is used for countersinking?
A countersink tool with conical cutting edges.
What speed is used in countersinking?
Half the drilling speed for the same hole.
What is spotfacing?
Producing a flat round surface around a drilled hole for bolt or nut seating.
What tool is used in spotfacing?
A spotfacing tool.
What is tapping?
Cutting internal threads using a tool called a tap.
What is a tap?
A multi-edge cutting tool used for threading.
How is tapping done?
By hand or machine, at a very slow cutting speed.
