DRILL MACHINE

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• 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) / 1000
  
  Where:

  • ➔ 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