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DRILLING MACHINE

Lecture # 1

Ravi Kumar K

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Drilling

Drilling is the operation of producing circular hole in thework-piece by using a rotating cutter called DRILL.

The machine used for drilling is called drilling machine.

The drilling operation can also be accomplished in lathe,in which the drill is held in tailstock and the work is held

by the chuck.

The most common drill used is the twist drill.

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Tool Nomenclature

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It is the simplest and accurate machine used inproduction shop.

The work piece is held stationary ie. Clamped in

position and the drill rotates to make a hole.

Types :Types :--a) Based on construction:

Portable, Sensitive,Radial, up-right, Gang,Multi-spindle

b)Based on Feed:

Hand and Power driven

Drilling Machine

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Sensitive Drilling Machine Drill holesfrom 1.5 to15mm

Operatorsenses the

cutting actionso sensitivedrillingmachine

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Radial Drilling Machine

It the largestand mostversatile

used frodrillingmedium tolarge and

heavy workpieces.

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Drill MaterialsThe two most common types are

1. HSS drill

- Low cost

2. Carbide- tipped drills

- high production and in CNC machines

Other types are

Solid Carbide drill, TiN coated drills, carbidecoated masonry drills, parabolic drills, split pointdrill

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Drilling And Drills

Types of drills

Twist drill: mostcommon drill

Step drill:

produces holesof two or moredifferentdiameters

Core drill: usedto make an

existing holebigger

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Drill fixed to the spindleDrilling operationsDrilling operations

Drilling Centre Hole

Drilling Deep Holes

Drilling ThinMaterial

Drilling Pilot Hole

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Tool Holding devices The different methods used for holding drill in

a drill spindle are

By directly fitting in the spindle hole. By using drill sleeve

By using drill socket

By using drill chuck

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Work Holding Devices

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Drilling Operations

Operations that can be performed in a drillingmachine are

DrillingReaming

Boring

Tapping

Counter boringCountersinking

Spot Facing

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Operations in drilling machine

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Operations in drilling machine

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Types of cutters

Reamers :-Multi tooth cutting tool

Accurate way of sizing and finishing the pre-existinghole.

Accuracy ofs0.005mm can be achieved

Boring Tool:-

Single point cutting tool.

Boring tool is held in the boring bar which has theshank.

Accuracy ofs0.005mm can be achieved.

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Types of cutters

Countersinks :-Special angled cone shaped enlargement at the end

of the hole

Cutting edges at the end of conical surface.Cone angles of 60, 82, 90, 100, 110, 120

Counter Bore Tool:-Special cutters uses a pilot to guide the cutting

action .

Accommodates the heads of bolts.

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Counter bore and spot facing

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Tapping:-

For cutting internal thread

Multi cutting edge tool.

Tapping is performed either

by hand or by machine.

Minor dia of the thread is

drilled and then tapping isdone.

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W

ork Holding Devices 1. Machine Table Vice