Q1: What is a Drilling Machine?
Ans: A drilling machine is a machine tool used to make round holes in a workpiece by using a rotating cutting tool called a drill.
Q2: State two uses of Drilling Machine.
Ans: Two uses of drilling machine are:
- ➔ To make holes in materials
- ➔ To enlarge existing holes
Q3: State the parts of the Drilling Machine.
Ans: Main parts of drilling machine are:
- ➔ Base
- ➔ Column
- ➔ Table
- ➔ Spindle
- ➔ Drill Head
- ➔ Motor
Q4: Define Drill Press.
Ans: A drill press is a fixed drilling machine in which the drill is mounted vertically and the workpiece is held on a table for accurate drilling.
Q5: State the types of Drilling Machine.
Ans: Types of drilling machines are:
- ➔ Hand Drill Machine
- ➔ Portable Drilling Machine
- ➔ Bench or Hand Feed Drilling Machine
- ➔ Back Geared Upright Drilling Machine
- ➔ Gang Drilling Machine
- ➔ Radial Drilling Machine
- ➔ Multiple Spindle Drilling Machine
- ➔ Turret Drilling Machine
Q6: Briefly explain the Hand Drill Machine.
Ans: A hand drill machine is a small manual tool operated by hand to drill holes in soft materials.
Q7: Briefly explain the Portable Drilling Machine.
Ans: A portable drilling machine is a lightweight electric tool that can be carried easily and used at different locations.
Q8: Briefly explain the Hand Feed Drilling Machine.
Ans: In this machine, the drill is fed into the workpiece manually by the operator using a hand lever.
Q9: Briefly explain the Back Geared up Right Drilling Machine.
Ans: This machine uses gear mechanisms to provide low speed and high torque, making it suitable for heavy drilling work.
Q10: Briefly explain the Gang Drilling Machine.
Ans: A gang drilling machine has several spindles arranged in a row, allowing multiple drilling operations on a workpiece.
Q11: Briefly explain the Radial Drilling Machine.
Ans: In a radial drilling machine, the drill head can move along a radial arm, making it suitable for large and heavy workpieces.
Q12: Briefly explain the Multiple Spindle Drilling Machine.
Ans: This machine has multiple spindles that can drill several holes at the same time, increasing productivity.
Q13: Briefly explain the Turret Drilling Machine.
Ans: A turret drilling machine has a rotating turret that holds different tools, allowing quick tool changes.
Q14: State the parts of Drill Press.
Ans: Parts of drill press are:
- ➔ Base
- ➔ Column
- ➔ Table
- ➔ Spindle
- ➔ Chuck
- ➔ Motor
- ➔ Feed Handle
Q15: What is NCS?
Ans: NCS stands for Number of Cutting Speeds. It refers to the different speeds available in a drilling machine for various operations.
Q16: State some operations of Drilling Machine.
Ans: Operations of drilling machine are:
- ➔ Drilling
- ➔ Reaming
- ➔ Tapping
- ➔ Boring
- ➔ Counter Boring
- ➔ Counter Sinking
- ➔ Spot Facing
Q17: Define Reaming.
Ans: Reaming is the process of finishing and slightly enlarging a drilled hole to obtain accurate size and smooth surface.
Q18: Define Tapping.
Ans: Tapping is the process of cutting internal threads inside a hole using a tool called a tap.
Q19: Define Boring.
Ans: Boring is the process of enlarging an already drilled hole using a single-point cutting tool.
Q20: Define Counter Boring.
Ans: Counter boring is the process of enlarging the top part of a hole to a larger diameter with a flat bottom.
Q21: Define Counter Sinking.
Ans: Counter sinking is the process of making a conical shape at the top of a hole to fit a screw head.
Q22: Define Spot Facing.
Ans: Spot facing is the process of machining a flat surface around a hole for proper seating of a bolt or nut.
Q23: What are Tool and Work Holding Devices? Name some.
Ans: Tool and work holding devices are used to hold the tool and workpiece firmly during drilling operations.
Examples are:
- ➔ Drill Chuck
- ➔ Vice
- ➔ Clamps
- ➔ Jig
Q24: Name some Tool Holding Devices.
Ans: Some tool holding devices are:
- ➔ Drill Chuck
- ➔ Drill Sleeve
- ➔ Drill Socket
- ➔ Collet
Q25: What is a Drill Chuck?
Ans: A drill chuck is a device used to hold the drill bit firmly in the spindle of a drilling machine.
Q26: What is a Drill Sleeve?
Ans: A drill sleeve is used to fit a smaller size drill shank into a larger spindle socket.
Q27: What is a Drill Socket?
Ans: A drill socket is used to connect the drill shank to the machine spindle when their sizes are different.
Q28: Name some Work Holding Devices.
Ans: Some work holding devices are:
- ➔ T-Bolt
- ➔ Step Blocks
- ➔ Strap Clamps
- ➔ Vice
- ➔ Vee Blocks
- ➔ Angle Plate
Q29: What is a T-Bolt?
Ans: A T-bolt is a bolt used in T-slots of machine tables to hold workpieces or fixtures securely.
Q30: What are Step-Blocks?
Ans: Step-blocks are support blocks with steps used along with clamps to adjust the height of the workpiece.
Q31: What are Strap-Clamps?
Ans: Strap clamps are flat metal strips used to hold the workpiece tightly on the machine table.
Q32: What are Vices?
Ans: Vices are mechanical devices used to hold the workpiece firmly during machining operations.
Q33: What are Vee-Blocks?
Ans: Vee-blocks are V-shaped devices used to hold cylindrical workpieces securely.
Q34: What is an Angle Plate?
Ans: An angle plate is a device used to hold the workpiece at a right angle (90°) to the machine table.
Q35: What are Jack Screws?
Ans: Jack screws are adjustable screws used to support and level the workpiece during machining.
Q36: What is a C-Clamp?
Ans: A C-clamp is a clamp shaped like the letter 'C' used to hold workpieces tightly in place.
Q37: What is Cutting Feed?
Ans: Cutting feed is the distance the cutting tool advances into the workpiece during one revolution or stroke.
Q38: What is Cutting Speed?
Ans: Cutting speed is the speed at which the cutting tool moves relative to the workpiece, usually measured in meters per minute (m/min).
Q39: Write the formula of Cutting Speed.
Ans: The formula of cutting speed is:
V = (π × D × N) / 1000Where:
- ➔ V = Cutting Speed (m/min)
- ➔ D = Diameter of drill (mm)
- ➔ N = Speed (rpm)
Q40: State the angles of Drill.
Ans: The main angles of a drill are:
- ➔ Point Angle
- ➔ Lip Clearance Angle
- ➔ Helix Angle
Q41: Briefly explain the procedure of Drill Grinding.
Ans: Procedure of drill grinding is:
- ➔ Hold the drill firmly
- ➔ Set the correct angle
- ➔ Grind one side of the drill point
- ➔ Grind the other side equally
- ➔ Check symmetry and sharpness
