University of Technology, Jamaica
237 Old Hope Road, Kingston 6

F.E.N.C
School of Engineering
Mechanical Workshop 1
Assignment # 1
Lathe, Milling Machines & Drill Press
Mr. E Bonnick
Name: Dean Rankine
ID #: 1105891
October21, 2014
Table of contents
Table of contents 2
INTRODUCTION 4 What is a lathe? 4
DIAGRAM OF LATHE MACHINE 5 FIG 1 5 FIG.2 6 HEADSTOCK 6 FEED AND LEAD SCREW …………... 10 FIG.3 11 CARRIAGE 11 CROSS SLIDE 12 COMPOUND REST 12 TOOL POST 13

FIG.4 13 TAILSTOCK 14 FIG.7 18 Single-Point Cutting Tool Variety 21 MILLING MACHINES 22
TYPES OF MILLING MACHINES 24
FIG.16 29
MILLING MACHINE PARTS AND FUNCTION 30
Milling Tools and Equipment 33
MILLING TOOLS AND EQUIPMENT 41
Collets, Spindle Adapters and Quick Change Tooling 44
Vises 47
Adjustable Angle Plate 48
Indexing Fixture 48
High Speed Milling Attachment 49 DRILL PRESS 51 Introduction 51 TOOLS AND EQUIPMENT 57
TWIST DRILLS 57
OTHER TYPES OF DRILL PRESS DEVICES 61
DRILL HOLDING DEVICES 63

REFERENCES 71

INTRODUCTION
What is a lathe?
A lathe is a machine tool which rotates the workpiece on its axis to perform various operations such as cutting, sanding, knurling, drilling, or deformation, facing, turning, with tools that are applied to the workpiece to create an object which has symmetry about an axis.
Lathes are used in woodturning, metalworking, metal spinning, thermal spraying, parts reclamation, and glass-working. Lathes can be used to shape pottery, the best-known design being the potter's wheel. Most suitably equipped metalworking lathes can also be used to produce most solids of revolution, plane surfaces and screw threads or helices. Ornamental lathes can produce three-dimensional solids of incredible complexity. The workpiece is usually held in place by either one or two centers, at least one of which can typically be moved horizontally to accommodate varying workpiece lengths. Other work-holding methods include clamping the work about the axis of rotation using a chuck or collet, or to a faceplate, using clamps or dogs.

DIAGRAM OF LATHE MACHINE

FIG 1

FIG.2

HEADSTOCK The lathe Headstock was once called the "Fixed Headstock" or "Fixed Head", and the rotating shaft within it the "Mandrel". It is mounted in a fixed position on the inner ways, usually at the left end. It uses a chuck to rotate the work.
The headstock (H1) houses the main spindle (H4), speed change mechanism (H2, H3), and change gears (H10). The headstock is required to be made as robust as possible due to the cutting forces involved, which can distort a lightly built housing, and induce harmonic vibrations that will transfer through to the workpiece, reducing the quality of the finished workpiece.
The main spindle is generally hollow to allow long bars to extend through to the work area, this reduces preparation and waste of material. The spindle then runs in precision bearings and is fitted with some means of attaching work holding devices such as chucks or faceplates. This end of the spindle will also have an included taper, usually Morse, to allow the insertion of tapers and centers. On older machines the spindle was directly driven by a flat belt pulley with the lower speeds available by manipulating the bull gear, later machines use a gear box driven by a dedicated electric motor. The fully geared head allows the speed selection to be done entirely through the gearbox. HEADSTOCK SPINDLE The end of the headstock spindle is usually machined so that it can carry a faceplate, chuck, drive-plate, internal or external collets - or even special attachments designed for particular jobs. In turn, these attachments hold the workpiece that is going to be machined.
The "fitting" formed on the end of the spindle is normally one of five types: 1) - a simple flange through which threaded studs on a faceplate or chuck (for example) can pass and be tightened into place with nuts. This is a secure method, and allows high-speed reverse, but is very inconvenient on a general-purpose lathe. 2) - A threaded nose onto which fittings screw. This is perfectly acceptable for smaller lathes, but unsatisfactory on larger industrial machines where, for reasons of production economy, the spindle may need to be reversed at high speed. Reversing a screwed-on chuck causes it to unscrew - with potentially disastrous results. 3) - A "D1-taper Camlock" fitting - a long-used, standard system that employs three or more "studs" that are turned to lock into the back of chucks and faceplates, etc. 4) - A taper - either of the simple Hardinge type or, for bigger lathes, the "taper-nose, long-key drive" - an older but excellent American design where a large screwed ring was held captive on the end of the spindle and used to draw the chuck, or other fitting, onto a long, keyed taper formed on the spindle end. An ideal system for the rigid mounting of heavier chucks, it has now largely fallen into disuse. The fitting was available in various sizes starting at L00 (L zero zero) and worked up through L0, L1, L2, etc. 5) - various fittings that became increasingly complex and apparently invented for the sake of being able to claim a National Standard. BED The bed of the lathe provides the foundation for the whole machine and holds the headstock, tailstock and carriage in alignment. The surfaces of the bed that are finely machined - and upon which the carriage and tailstock slide - are known as "ways". The bed is a robust base that connects to the headstock and permits the carriage and tailstock to be aligned parallel with the axis of the spindle. This is facilitated by hardened ground ways which restrain the carriage and tailstock in a set track. The carriage travels by means of a rack and pinion system, lead screw of accurate pitch, or feed screw.
Some beds have a gap near the headstock to allow extra-large diameters to be turned. Sometimes the gap is formed by the machined ways stopping short of the headstock, sometimes by a piece of bed that can be unbolted, removed--and lost. Some very large lathes have a "sliding bed" where the upper part, on which the carriage and tailstock sit, can be slid along a separate lower part - and so make the gap correspondingly larger or smaller.

Lathe bed
FEED AND LEAD SCREW Originally termed a "master thread", or described as the "leading screw", but now always referred to as the "lead screw", this is a long threaded rod normally found running along the front of the bed or, on some early examples running between the bed ways down the bed's center line. It uses a train of gears to connect the lathe spindle to the lead screw and the lead screw to the lathe carriage . The feed screw (H8) is a long driveshaft that allows these series of gears to drive the carriage mechanisms. These gears are located in the apron of the carriage. Both the feed screw and lead screw (H9) are driven by either the change gears (on the quadrant) or an intermediate gearbox known as a quick change gearbox (H6) or Norton gearbox. These intermediate gears allow the correct ratio and direction to be set for cutting threads or worm gears. Tumbler gears (operated by H5) are provided between the spindle and gear train along with quadrant plate that enables a gear train of the correct ratio and direction to be introduced. This provides a constant relationship between the numbers of turns the spindle makes, to the number of turns the lead screw makes. This ratio allows screw threads to be cut on the workpiece without the aid of a die.
The lead screw is manufactured to either imperial or metric standards and will require a conversion ratio to be introduced to create thread forms from a different family. To accurately convert from one thread form to the other requires a 127-tooth gear, or on lathes not large enough to mount one, an approximation may be used. Multiples of 3 and 7 giving a ratio of 63:1 can be used to cut fairly loose threads. This conversion ratio is often built into the quick change gearboxes.

FIG.3

CARRIAGE
The whole assembly of Saddle, Apron, Top and Cross Slide is known as the "Carriage”. In its simplest form the carriage holds the tool bit and moves it longitudinally (turning) or perpendicularly (facing) under the control of the operator. The operator moves the carriage manually via the hand wheel (5a) or automatically by engaging the feed shaft with the carriage feed mechanism (5c). This provides some relief for the operator as the movement of the carriage becomes power assisted. The hand wheels (2a, 3b, 5a) on the carriage and its related slides are usually calibrated, both for ease of use and to assist in making reproducible cuts. The Carriage
CROSS SLIDE
The cross-slide stands atop the carriage and has a feeds crew that travels perpendicular to the main spindle axis. This permits facing operations to be performed, and the depth of cut to be adjusted. This feeds crew can be engaged, through a gear train, to the feed shaft to provide automated 'power feed' movement to the cross-slide. On most lathes, only one direction can be engaged at a time as an interlock mechanism will shut out the second gear train.
The Cross slide
COMPOUND REST The compound rest (or top slide) is the part of the machine where the tool post is mounted. It provides a smaller amount of movement along its axis via another feeds crew. The compound rest axis can be adjusted independently of the carriage or cross-slide.
The advantage of a quick change set-up is to allow an unlimited number of tools to be used (up to the number of holders available) rather than being limited to 1 tool with the lantern style, or 3 to 4 tools with the 4 sided type. Interchangeable tool holders allow the all the tools to be preset to a center height that will not change, even if the holder is removed from the machine.
It is utilized when turning tapers, to control depth of cut when screw cutting or precision facing, or to obtain finer feeds (under manual control) than the feed shaft permits.

TOOL POST The tool bit is mounted in the tool post which may be of the American lantern style, traditional 4 sided square style, or in a quick change style such as the multifix arrangement, or in a quick change style such as the multifix arrangement .The advantage of a quick change set-up is to allow an unlimited number of tools to be used (up to the number of holders available) rather than being limited to 1 tool with the lantern style, or 3 to 4 tools with the 4 sided type. Interchangeable tool holders allow the all the tools to be preset to a center height that will not change, even if the holder is removed from the machine.

FIG.4

TAILSTOCK The Tailstock is arranged to slide along the bed and can be locked to it at any convenient point. The upper portion of the unit is fitted with what is called a "barrel", "spindle" "ram" or "shoot" that can be moved in and out of the main casting by hand, lever or screw feed and carries a "Dead Centre" that supports the other end of the work held in the headstock.
Special centers, which rotate with the work, can be used in the tailstock; these are known as "Rotating Centers".
The tailstock is a tool holder directly mounted on the spindle axis, opposite the headstock. The spindle (T5) does not rotate but does travel longitudinally under the action of a lead screw and hand wheel (T1). The spindle includes a taper to hold drill bits, centers and other tooling. The tailstock can be positioned along the bed and clamped (T6) in position as required. There is also provision to offset the tailstock (T4) from the spindles axis, this is useful for turning small tapers.
The image shows a reduction gear box (T2) between the hand wheel and spindle, this is a feature found only in the larger center lathes, where large drills may necessitate the extra leverage. FIG.5 Tail Stock
SADDLE
The casting that fits onto the top of the bed and slides along it is known, almost universally, as the "Saddle" - a self-explanatory and very suitable term.

APRON The vertical, often flat and rectangular "plate" fastened to the front of the "Saddle" is known as the "Apron" and carries a selection of gears and controls that allow the carriage to be driven (by hand or power) up and down the bed. The mechanism inside can also engage the screw cutting feed and various powered tool feeds, if they are fitted. The lead screw, and sometimes a power shaft as well, are often arranged to pass through the apron and provide it with a drive for the various functions. Virtually all screw-cutting lathes have what is commonly-called a "half-nut" lever that closes down one and sometimes two halves of a split nut to grasp the lead screw and provide a drive for screw cutting. Apron design can be roughly divided into "single-wall" and "double-wall" types. The "single-wall" apron has just one thickness of metal and, protruding from it (and unsupported on their outer ends) are studs that carry gears. The "double-wall" apron is a much more robust structure, rather like a narrow, open-topped box with the gear-carrying studs fitted between the two walls - and hence rigidly supported at both ends. This type of construction produces a very stiff structure - and one that is far less likely to deflect under heavy-duty work; another advantage is that the closed base of the "box" can be used to house an oil reservoir the lubricant ion which is either splashed around or, preferably, pumped to supply the spindles, gears and on some lathes, the sliding surfaces of the bed and cross slide as well.

FIG.6 the Apron

Operations that can be performed by a Lathe 1) Facing
Facing is the removal of wood or metal from a cylindrical work piece. This creates a smooth surface. In this operation the work piece is held in the chuck and the facing tools is fed from the center of the work piece toward the other surface with the help of a cross slide. However, if you use a chuck you can face rectangular, square or other unusual-shaped pieces. When facing, begin with a slower speed and gradually increase to a faster speed. Also, the work piece should not extend farther out of the lathe than around three times its own size. When facing, gouges, parting and chisel tools can be used to create the desired results.

2) Turning
Turning is when a turning tool is applied to the work piece to create groves, ridges and indents in the work piece. Turning creates metal or wood chips as the piece turns on the lathe. The work piece spins between two end points to hold it in place. The speed can be adjusted as necessary depending on the size of the work piece and the desired results. Such tools to use are a captive ring chisel, a decorative bead chisel or a scraper.
Plat turning: It is an operation of removing excess amount of materials from the surface of the cylindrical in the chuck or between centers and longitudinal feed is given to the tools either by hand or power.
A small 3) Taper turning: It is an operation of producing of external conical surface on a work piece. taper may be produced with the help of a chamfering tool.
4) Step Turning: It is an operation of producing various steps of different diameter in the work piece. This operation is carried out in the similar ways as plain turning.
5) Drilling: It is an operation of making of hole in a work piece with the help of a drill. In this operation the work piece is held in a chuck and the drill is held in the tailstock.
6) Reaming: It is an operation of finishing the previously drilled hole. In this operation the work is held in a tail stock and it is fed into the hole in the similar ways as for drilling.
7) Threading: It is an operation of cutting helical grooves on the external cylindrical surface of work piece. In this operation the work is held in a chuck or between centers and the threading tools is fed longitudinally to the revolving work.
8) Knurling: It is an operation of providing knurled surface of the work piece. In this operation a knurled tool is moved longitudinally to a revolving work piece surface.

Types of Tools used on a lathe | Knurling is an operation used to produce a texture on a turned machine part. Handles are often knurled in order to provide a gripping surface. The two wheel inserts shown on the tool below contact the work piece, and with pressure, cold-form a pattern into the surface of the part.

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FIG.7

Turning | The chuck is integral to a lathe's functioning because it fixtures the part to the spindle axis of the machine. Below is shown a three-jaw chuck with jaws that are all driven by the same chuck key. This arrangement provides convenience in that parts can be mounted and dismounted quickly. FIG.8Three-Jaw ChuckThe inner construction of the three-jaw chuck is shown below. A spiral gear meshes with cog teeth on the jaws to move all three jaws in or out simultaneously. Parts can be fixed on the outer or inner surfaces since there are gripping surfaces on the inner and outer surfaces of the chuck jaws.

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FIG.9
| Four-Jaw ChuckIf the part needs to be off center or is not a solid of revolution (axially symmetric), a four-jaw chuck with independently-actuated jaws needs to be used. This type of chuck is depicted below.
FIG.10
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Single-Point Cutting Tool Variety
There are many types of cutting tools for different operations. Below is shown a few of the variety, here shown with a tool holder adapter that fits into a larger tool post fixture.

FIG.11
MILLING MACHINES Milling Machines are tools designed to machine metal, wood, and other solid materials. Often automated, milling machines can be positioned in either vertical or horizontal orientation to carve out materials based on a pre-existing design. These designs are often CAD directed, and many milling machines are CNC-operated, although manually and traditionally-automated milling devices are also common. Milling machines are capable of dynamic movement, both of the tool and the workpiece, and many milling machines can perform multi-axis machining. Because of variations in orientation, operation and application, milling machines have varying functions and different operating principles.
Tooling
Milling machines can be outfitted with a number of tool heads to accomplish different machining needs. Some of these tool heads include cutters, rounding mills, fluted mills and ball end mills. Some milling machines have rotating tool ends that can change depending on the needed task,-computer programming communicates with the machine when to change its tooling.
The different tooling used in milling machines is based on material and desired shape. Because materials like wood and steel have different physical properties, different tool bits are needed to properly machine the materials. If a milling machine uses a tool bit that is not strong enough to machine steel, the tooling and even the machine itself can be damaged. Tooling that is too strong for softer materials can damage the workpiece. The basic tooling bit on a milling machine is called the cutter. A cutter is a shaped bar that has Saw teeth. The cutter rotates rapidly to cut down and shape materials. The cutter is attached to an arbor, which is sometimes called a mandrel or mandrill, a shaped bar that varies in size, length and ending, and is used to hold the cutter firmly.
A milling cutter’s saw ending can be spaced, sized and oriented in many ways. Generally, the teeth are either positioned in a straight up-and-down orientation, or angled in a helical orientation. Straight teeth are preferable in operations on denser materials, while helical teeth can create very smooth cuts on softer materials. There are a variety of cutters within these categories, including dense end cutters, t-slot cutters, and angle cutters. Cutters are subject to different standardized sizes, with CAT sizes as the most commonly-used standardization category in the United States.

TYPES OF MILLING MACHINES
KNEE-TYPE MILLING MACHINE Knee-type milling machines are characterized by a vertically adjustable worktable resting on a saddle which is supported by a knee. The knee is a massive casting that rides vertically on the milling machine column and can be clamped rigidly to the column in a position where the milling head and milling machine spindle are properly adjusted vertically for operation.
The plain vertical machines are characterized by a spindle located vertically, parallel to the column face, and mounted in a sliding head that can be fed up and down by hand or power. Modern vertical milling machines are designed so the entire head can also swivel to permit working on angular surfaces. The turret and swivel head assembly is designed for making precision cuts and can be swung 360° on its base. Angular cuts to the horizontal plane may be made with precision by setting the head at any required angle within a 180" arc.
The plain horizontal milling machine's column contains the drive motor and gearing and a fixed position horizontal milling machine spindle. An adjustable overhead arm containing one or more arbor supports projects forward from the top of the column. The arm and arbor supports are used to stabilize long arbors. Supports can be moved along the overhead arm to support the arbor where support is desired depending on the position of the milling cutter or cutters. The milling machine's knee rides up or down the column on a rigid track. A heavy, vertical positioning screw beneath past the milling cutter.
The milling machine is excellent for forming flat surfaces, cutting dovetails and keyways, forming and fluting milling cutters and reamers, cutting gears, and so forth. Many special operations can be performed with the attachments available for milling machine use. The knee is used for raising and lowering. The saddle rests upon the knee and supports the worktable. The saddle moves in and out on a dovetail to control cross feed of the worktable. The worktable traverses to the right or left upon the saddle for feeding the workpiece past the milling cutter. The table may be manually controlled or power fed.

FIG.12
UNIVERSAL HORIZONTAL MILLING MACHINE
The basic difference between a universal horizontal milling machine and a plain horizontal milling machine is the addition of a table swivel housing between the table and the saddle of the universal machine. This permits the table to swing up to 45° in either direction for angular and helical milling operations. The universal machine can be fitted with various attachments such as the indexing fixture, rotary table, slotting and rack cutting attachments, and various special fixtures.

FIG.13

RAM-TYPE MILLING MACHINE The ram-type milling machine is characterized by a spindle mounted to a movable housing on the column to permit positioning the milling cutter forward or rearward in a horizontal plane. Two popular ram-type milling machines are the universal milling machine and the swivel cutter head ram-type milling machine.

FIG.14

UNIVERSAL RAM-TYPE MILLING MACHINE
The universal ram-type milling machine is similar to the universal horizontal milling machine, the difference being, as its name implies, the spindle is mounted on a ram or movable housing.

FIG.15

SWIVEL CUTTER HEAD RAM-TYPE MILLING MACHINE
The cutter head containing the milling machine spindle is attached to the ram. The cutter head can be swiveled from a vertical spindle position to a horizontal spindle position or can be fixed at any desired angular position between vertical and horizontal. The saddle and knee are hand driven for vertical and cross feed adjustment while the worktable can be either hand or power driven at the operator's choice.

FIG.16

MILLING MACHINE PARTS AND FUNCTION

* Base
The base of the machine is Grey iron casting accurately machined on its top and bottom surface and serves as a foundation member for all the other parts which rest upon it. It carries the column at its one end. In some machines, the base is hollowed and working as a reservoir for cutting fluid. * Column
The column is the main supporting frame mounted vertically on the base. The column is box shaped. Heavily ribbed inside and houses all the driving mechanisms for the spindle and table feed. The front vertical face of the column is accurately machined and is provided with dovetail guide ways of supporting knee. The top of the column is finished to hold an over-arm that extends outward at the front of the machine. * Knee
The knee is the rigid gray iron casting that slides up and down on the vertical way of the column face. The adjustment of height is effected by elevating screw on the base that also supports the knee. The knee houses the feed mechanism of the table, and in different controls to operate it. The top face of the knee forms slid way for the saddle to provide cross travel of the table.

* Saddle
The saddle is placed on the top of the knee, which slides on guide ways set exactly at 90 to column face. A cross feed screw near the top of the knee engages a nut of the bottom of the saddle to move it horizontally, by hand or power, to apply cross feed. The top of the saddle is accurately machined to provide guide ways for the table. * Table
The table rest on ways on the saddle and travels longitudinally. The top of the table is accurately finished and T-slots are provided for clamping the work and other fixtures on it. A lead screw under the table engages a nut on the saddle to move the table horizontally by hand or power. The longitudinal travel of the table may be limited by fixing trip dogs on the side of the table. In universal machines, the table may also be swiveled horizontally. For this purpose the table is mounted on a circular base which in its turn is mounted on the saddle. The circular bagel is graduated in the degree. * Over hanging arm
Over hanging arm is mounted on the top of column extends beyond the column face and serve as a bearing support may be provided nearest to the cutter. More than one bearing support may be provided for the arbor. * Front Brace
The front brace is an extra support that is fitted between the knee and over arm to ensure further rigidity to the arbor and the knee. The front brace is slotted to allow for adjustment of the height of the knee relative to over arm. * Spindle
The spindle of the machine is locates in the upper part of the column and receive power from the motor through belts, gears and clutches and transmit it to the arbor the front end of the spindle just projects from the column face and it is provided with a tapered hole into to which various cutting tools and arbors may be inserted. The accuracy in metal machining by the cutter depends on primarily accuracy, strength and rigidity of the spindle. * Arbor
An arbor is considered as an extension of the machine spindle on which cutters are securely mounted and rotated. The arbors are made with taper shanks for proper alignments with machine spindles having taper hole on their nose. The taper shank of the arbor conforms to the Morse taper or self-release taper whose value is 7:24. The arbor may be supported at the farthest end from the overhanging arm or may be of cantilever type which is called stub arbor.

Milling Tools and Equipment Classification of Milling Cutters |
Milling cutters are usually made of high-speed steel and are available in a great variety of shapes and sizes for various purposes. It is important to know the names of the most common classifications of cutters, their uses, and, the sizes best suited to the work at hand.
The pitch of the cutter is determined by the number of teeth. The tooth face is the forward facing surface of the tooth that forms the cutting edge. The cutting edge is the angle on each tooth that performs the cutting. The land is the narrow surface behind the cutting edge on each tooth. The rake angle is the angle formed between the face of the tooth and the centerline of the cutter. The rake angle defines the cutting edge and provides a path for chips that are cut from the workpiece. The primary clearance angle is the angle of the land of each tooth measured from a line tangent to the centerline of the cutter at the cutting edge. This angle prevents each tooth from rubbing against the workpiece after it makes its cut. This angle defines the land of each tooth and provides additional clearance for passage of cutting oil and chips. The diameter of the hole determines the size of the arbor necessary to mount the milling cutter. Plain milling cutters that are more than 3/4 inch in width are usually made with spiral or helical teeth. A plain spiral-tooth milling cutter produces a better and smoother finish and requires less power to operate. A plain helical-tooth milling cutter is especially desirable when milling an uneven surface or one with holes in it.

Left and right hand cutters

Types of Teeth
The teeth of milling cutters may be made for right-hand or left-hand rotation, and with either right-hand or left-hand helix. Determine the hand of the cutter by looking at the face of the cutter when mounted on the spindle. A right-hand cutter must rotate counterclockwise; a left-hand cutter must rotate clockwise. The right-hand helix is shown by the flutes leading to the right; a left-hand helix is shown by the flutes leading to the left. The direction of the helix does not affect the cutting ability of the cutter, but take care to see that the direction of rotation is correct for the hand of the cutter.

Plain and helical milling cutters

Saw Teeth Saw teeth are either straight or helical in the smaller sizes of plain milling cutters, metal slitting saw milling cutters, and end milling cutters. The cutting edge is usually given about 5 degrees primary clearance. Sometimes the teeth are provided with off-set nicks which break up chips and make coarser feeds possible.
Helical Milling Cutters The helical milling cutter is similar, to the plain milling cutter, but the teeth nave a helix angle of 45° to 60°. The steep helix produces a shearing action that results in smooth, vibration-free cuts. They are available for arbor mounting, or with an integral shank with or without a pilot. This type of helical cutter is particularly useful for milling elongated slots and for light cuts on soft metal. See Figure 4-5.
Metal Slitting Saw Milling Cutter
The metal slitting saw milling cutter is essentially a very thin plain milling cutter. It is ground slightly thinner toward the center to provide side clearance. These cutters are used for cutoff operations and for milling deep, narrow slots, and are made in widths from 1/32 to 3/16 inch.

Various milling cutters.

Side Milling Cutters
Side milling cutters are essentially plain milling cutters with the addition of teeth on one or both sides. A plain side milling cutter has teeth on both sides and on the periphery. When teeth are added to one side only, the cutter is called a half-side milling cutter and is identified as being either a right-hand or left-hand cutter. Side milling cutters are generally used for slotting and straddle milling. Interlocking tooth side milling cutters and staggered tooth side milling cutters are used for cutting relatively wide slots with accuracy. Interlocking tooth side milling cutters can be repeatedly sharpened without changing the width of the slot they will machine. After sharpening, a washer is placed between the two cutters to compensate for the ground off metal. The staggered tooth cutter is the most washer is placed between the two cutters to compensate for efficient type for milling slots where the depth exceeds the width.

End Milling Cutters The end milling cutter, also called an end mill, has teeth on the end as well as the periphery. The smaller end milling cutters have shanks for chuck mounting or direct spindle mounting. End milling cutters may have straight or spiral flutes. Spiral flute end milling cutters are classified as left-hand or right-hand cutters depending on the direction of rotation of the flutes. If they are small cutters, they may have either a straight or tapered shank. The most common end milling cutter is the spiral flute cutter containing four flutes. Two-flute end milling cutters, sometimes referred to as two-lip end mill cutters, are used for milling slots and key ways where no drilled hole is provided for starting the cut. These cutters drill their own starting holes. Straight flute end milling cutters are generally used for milling both soft and tough materials, while spiral flute cutters are used mostly for cutting steel. Large end milling cutters (normally over two inches in diameter) are called shell end mills and are recessed on the face to receive a screw or nut for mounting on a separate shank or mounting on an arbor, like plain milling cutters. The teeth are usually helical and the cutter is used particularly for face milling operations requiring the facing of two surfaces at right angles to each other.

T-Slot Milling Cutter
The T-slot milling cutter is used to machine T-slot grooves in worktables, fixtures, and other holding devices. The cutter has a plain or side milling cutter mounted to the end of a narrow shank. The throat of the T-slot is first milled with a side or end milling cutter and the head space is then milled with the T-slot milling cutter.

Woodruff Key slot Milling Cutters
The Woodruff key slot milling cutter is made in straight, tapered-shank, and arbor-mounted types. The most common cutters of this type, under 1 1/2 inches in diameter, are provided with a shank. They have teeth on the periphery and slightly concave sides to provide clearance. These cutters are used for milling semi cylindrical key ways in shafts.

End mill, T-slot, and woodruff key way cutters
Angle Milling Cutters
The angle milling cutter has peripheral teeth which are neither parallel nor perpendicular to the cutter axis. Common operations performed with angle cutters are cutting V-notches and serrations. Angle cutters may be single-angle milling cutters or double-angle milling cutters. The single-angle cutter contains side-cutting teeth on the flat side of the cutter. The angle of the cutter edge is usually 30°, 45°, or 60°, both right and left. Double-angle cutters have included angles of 45, 60, and 90 degrees.
Gear Hob
The gear hob is a formed tooth milling cutter with helical teeth arranged like the thread on a screw. These teeth- are fluted to produce the required cutting edges. Hobs are generally used for such work as finishing spur gears, spiral gears, and worm gears. They may also be used to cut ratchets and spline shafts.
Concave and Convex Milling Cutters
Concave and convex milling cutters are formed tooth cutters shaped to produce concave and convex contours of 1/2 circle or less. The size of the cutter is specified by the diameter of the circular form the cutter produces.

Angle, concave, convex, and gear cutters

Corner Rounding Milling Cutter
The corner-rounding milling cutter is a formed tooth cutter used for milling rounded corners on workplaces up to and including one-quarter of a circle. The size of the cutter is specified by the radius of the circular form the cutter produces, such as concave and convex cutters generally used for such work as finishing spur gears, spiral gears, and worm wheels. They may also be used to cut ratchets and spline shafts.
Special Shaped-Formed Milling Cutter
Formed milling cutters have the advantage of being adaptable to any specific shape for special operations. This cutter is specially made for each specific job. In the field, a fly cutter is formed by grinding a single point lathe cutter bit for mounting in a bar, holder, or fly cutter arbor. The cutter can be sharpened many times without destroying its shape.

MILLING TOOLS AND EQUIPMENT Milling machine arbors are made in various lengths and in standard diameters of 7/8, 1, 1 1/4, and 1 1/2 inch. The shank is made to fit the taper hole in the spindle while the other end is threaded. The threaded end may have left or right-handed threads. The milling machine spindle may be self-holding or self-releasing. The self-holding taper is held in the spindle by the high wedging force. The spindle taper in most milling machines is self-releasing; tooling must be held in place by a draw bolt extending through the center of the spindle. Arbors are supplied with one of three tapers to fit the milling machine spindle: the Standard Milling Machine taper, the Brown and Sharpe taper, and the Brown and Sharpe taper with tang. The Standard Milling Machine Taper is used on most machines of recent manufacture. See Figure 4-11. These takers are identified by the number 30, 40, 50, or 60. Number 50 is the most commonly used size on all modern machines.
The Brown and Sharpe taper is found mostly on older machines. Adapters or collets are used to adapt these tapers to fit machines whose spindles have Standard Milling Machine tapers. The Brown and Sharpe taper with tang is used on some older machines. The tang engages a slot in the spindle to assist in driving the arbor.
Standard Milling Machine Arbor
The standard milling machine arbor has a tapered, cylindrical shaft with a standard milling taper on the driving end and a threaded portion on the opposite end to receive the arbor nut. One or more milling cutters may be placed on the straight cylindrical portion of the arbor and held in position by sleeves and the arbor nut. The standard milling machine arbor is usually splined and keys are used to lock each cutter to the arbor shaft. These arbors are supplied in three styles, various lengths and, standard diameters. The most common way to fasten the arbor in the milling machine spindle is to use a draw bar. The bar threads into the taper shank of the arbor to draw the taper into the spindle and hold it in place. Arbors secured in this manner are removed by backing out the draw bar and tapping the end of the bar to loosen the taper. The end of the arbor opposite the taper is supported by the arbor supports of the milling machine. One or more supports reused depending on the length of the arbor and the degree of rigidity required. The end may be supported by a lathe center bearing against the arbor nut or by a bearing surface 0f the arbor fitting inside a bushing of the arbor support.

Tapers used for milling machine arbors |
Standard milling machine arbor

Screw Arbor
Screw arbors are used to hold small cutters that have threaded holes. These arbors have a taper next to the threaded portion to provide alignment and support for tools that require a nut to hold them against a taper surface. A right-hand threaded arbor must be used for right-hand cutters while a left-hand threaded arbor is used to mount left-hand cutters.

Slitting Saw Milling Cutter Arbor
The slitting saw milling cutter arbor is a short arbor having two flanges between which the milling cutter is secured by tightening a clamping nut. This arbor is used to hold metal slitting saw milling cutters used for slotting, slitting, and sawing operations.
Shell End Milling Cutter Arbor
The shell end milling cutter arbor has a bore in the end in which shell end milling cutters fit and are locked in place by means of a cap screw.
The fly cutter arbor is used to support a single-edge lathe, shaper, or planer cutter bit for boring and gear cutting operations on the milling machine

Arbor variations.

Collets, Spindle Adapters and Quick Change Tooling
A collet is a form of a sleeve bushing for reducing the size of the hole in the milling machine spindle so that small shank tools can be fitted into large spindle recesses .They are made in several forms, similar to drilling machine sockets and sleeves, except that their tapers are not alike.

Solid and spring collets

Spindle Adapters A spindle adapter is a form of a collet having a standardized spindle end. They are available in a wide variety of sizes to accept cutters that cannot be mounted on arbors. They are made with either the Morse taper shank or the Brown and Sharpe taper with tang having a standard spindle end.

Milling machine adaptors
Chuck Adapter
A chuck adapter is used to attach chucks to milling machines having a standard spindle end. The collet holder is sometimes referred to as a collet chuck. Various forms of chucks can be fitted to milling machines spindles for holding drills, reamers, and small cutters for special operations.

Chuck adaptor.

Quick-Change Tooling The quick-change adapter mounted on the spindle nose is used to speed up tool changing. Tool changing with this system allows you to set up a number of milling operations such as drilling, end milling, and boring without changing the setup of the part being machined. The tool holders are mounted and removed from a master holder mounted to the machine spindle by means of a clamping ring.

Quick-change adaptor and tool holder

Vises Either a plain or swivel-type vise is furnished with each milling machine. The plain vise, similar to the machine table vise, is used for milling straight workplaces and is bolted to the milling machine table either at right angles or parallel to the machine arbor. The swivel vise can be rotated and contains a scale graduated in degrees at its base to facilitate milling workplaces at any angle on a horizontal plane. The universal vise, which may be obtained as extra equipment, is designed so that it can be set at both horizontal and vertical angles. This type of vise maybe used for flat and angular milling. The all-steel vise is the strongest setup because the workpiece is clamped closer to the table. The vise can securely fasten castings, forgings, and rough-surfaced workplaces. The jaw can be positioned in any notch on the two bars to accommodate different shapes and sizes. The air or hydraulically operated vise is used more often in production work. This type of vise eliminates tightening by striking the crank with a lead hammer or other soft face hammer.
Adjustable Angle Plate
The adjustable angle plate is a workpiece holding device, similar to the universal vise in operation. Work pieces are mounted to the angle plate with T-bolts and clamps in the same manner used to fasten workplaces to the worktable of the milling machine. The angle plate can be adjusted to any angle so that bevels and tapers can be cut without using a special milling cutter or an adjustable cutter head.
Indexing Fixture
The index fixture consists of an index head, also called a dividing head, and footstock which is similar to the tailstock of a lathe. The index head and footstock attach to the worktable of the milling machine by T-slot bolts. An index plate containing graduations is used to control the rotation of the index head spindle. The plate is fixed to the index head, and an index crank, connected to the index head spindle by a worm gear and shaft. Work pieces are held between centers by the index head spindle and footstock. Work pieces may also be held in a chuck mounted to the index head spindle or may be fitted directly into the taper spindle recess of some indexing fixtures. There are many variations of the indexing fixture. Universal index head is the name applied to an index head designed to permit power drive of the spindle so that helixes may be cut on the milling machine. Gear cutting attachment is another name applied to an indexing fixture; in this case, one that is primarily intended for cutting gears on the milling machine.

Indexing fixture.

High Speed Milling Attachment
The rate of spindle speed of the milling machine may be increased from 1 1/2 to 6 times by using the high-speed milling attachment. This attachment is essential when using cutters and twist drills which must be driven at a high rate of speed in order to obtain an efficient surface speed. The attachment is clamped to the column of the machine and is driven by a set of gears from the milling machine spindle.
VERTICAL SPINDLE ATTACHMENT This vertical spindle attachment converts the horizontal spindle of a horizontal milling machine to a vertical spindle. It is clamped to the column and driven from the horizontal spindle. It incorporates provisions for setting the head at any angle, from the vertical to the horizontal, in plane and right angles to the machine spindle. End milling and face milling are more easily accomplished with this attachment, because the cutter and the surface being cut are in plain view.

UNIVERSAL MILLING ATTACHMENT
This device is similar to the vertical spindle attachment but is more versatile. The butter head can be swiveled to any angle in any plane, whereas the vertical spindle attachment only rotates in one place from horizontal to vertical.
ROTARY TABLE OR CIRCULAR MILLING ATTACHMENT
This attachment consists of similar worktable containing T-slots for mounting workplaces. The circular table revolves on a base attached to the milling machine worktable. The attachment can be either hand or power driven, being connected to the table drive shaft if power driven. It may be used for milling circles, angular indexing, arcs, segments, circular slots, grooves, and radii, as well as for slotting external and internal gears. The table of the attachment is divided in degrees.

Rotary table (circular milling attachment.
DRILL PRESS
Introduction
A drilling machine comes in many Shapes and sizes, from small hand-held power drills to bench mounted and finally floor-mounted models. They can perform operations other than drilling, such as countersinking, counter boring, reaming, and tapping large or small holes. A drilling machine, called a drill press, is used to cut holes into or through metal, wood, or other materials. Drilling machines use a drilling tool that has cutting edges at its point. This cutting tool is held in the drill press by a chuck or Morse taper and is rotated and fed into the work at variable speeds.
Drilling machines may be used to perform other operations. They can perform countersinking, boring, counter boring, spot facing, reaming, and tapping. Drill press operators must know how to set up the work, set speed and feed, and provide for coolant to get an acceptable finished product. The size or capacity of the drilling machine is usually determined by the largest piece of stock that can be center-drilled. For instance, a 15-inch drilling machine can center-drill a 30-inch-diameter piece of stock. Other ways to determine the size of the drill press are by the largest hole that can be drilled, the distance between the spindle and column, and the vertical distance between the worktable and spindle.

CHARACTERISTICS of A Drill Press All drilling machines have the following construction characteristics (1).The Spindle.(2) Sleeve or Quill,(3) Column,(4) Head, (5) Worktable, and(6) the Base. * The Spindle holds the drill or cutting tools and revolves in a fixed position in a sleeve. In most drilling machines, the spindle is vertical and the work is supported on a horizontal table. * The Sleeve or Quill assembly does not revolve but may slide in its bearing in a direction parallel to its axis. When the sleeve carrying the spindle with a cutting tool is lowered, the cutting tool is fed into the work: and when it is moved upward, the cutting tool is withdrawn from the work. Feed pressure applied to the sleeve by hand or power causes the revolving drill to cut its way into the work a few thousandths of an inch per revolution. * The Column of most drill presses is circular and built rugged and solid. The column supports the head and the sleeve or quill assembly. * The Head of the drill press is composed of the sleeve, spindle, electric motor, and feed mechanism. The head is bolted to the column. * The Worktable is supported on an arm mounted to the column. The worktable can be adjusted vertically to accommodate different heights of work or it may be swung completely out of the way. It may be tilted up to 90° in either direction, to allow for long pieces to be end or angled drilled. * The Base of the drilling machine supports the entire machine and when bolted to the floor, provides for vibration-free operation and best machining accuracy. The top of the base is similar to a worktable and maybe equipped with T-slots for mounting work too large for the table.

Drill Press

DRILL PRESS

TYPES OF DRILLING MACHINES
There are two types of drilling machines used by maintenance personnel for repairing and fabricating needed parts. They are the Hand-feed and the Power-feed. Other types of drilling machines, such as the radial drill press, numerically controlled drilling machine, multiple spindle drilling machine, gang drilling machine, and turret drill press, are all variations of the basic hand and power-feed drilling machines. They are designed for high-speed production and industrial shops.
Drilling depth is controlled by a depth-stop mechanism located on the side of the spindle. The operator of the machine must use a sense of feel while feeding the cutting tool into the work. The operator must pay attention and be alert to the drill as it breaks through the work, because of the tendency of the drill to grab or snag the workpiece, wrenching it free of its holding device. Due to the high speed of these machines, operations that require drilling speeds less than 450 revolutions per minute cannot be performed.
Power-Feed
The power-feed drilling machines are usually larger and heavier than the hand-feed. They are equipped with the ability to feed the cutting tool into the work automatically, at a preset depth of cut per revolution of the spindle, usually in thousandths of an inch per revolution. These machines are used in maintenance shops for medium-duty work, or work that uses large drills that require power feeds. The power-feed capability is needed for drills or cutting took that are over 1/2 inch in diameter, because they require more force to cut than that which can be provided by using hand pressure. The speeds available on power-feed machines can vary from about 50 RPM to about 1,800 RPM. The slower speeds allow for special operations, such as counter boring, counter- sinking, and reaming.
The sizes of these machines generally range from 17-inch to a 22-inch center-drilling capacity, and are usually floor mounted. They can handle drills up to 2 inches in diameter, which mount into tapered Morse sockets. Larger workplaces are usually clamped directly to the table or base using T-bolts and clamps, while small workplaces are held in a vise. A depth-stop mechanism is located on the head, near the spindle, to aid in drilling to a precise depth. Reaming, counter boring, and counter-sinking may require slower speeds than drilling and may not be able to be performed for all materials on these machines.

Power-feed drilling machine
Hand-Feed
The hand-feed drilling machines (Figure 6-5) are the simplest and most common type of drilling machines in use today. These are light duty machines that are hand-fed by the operator, using a feed handle. So that the operator is able to "feel" the action of the cutting tool as it cuts through the workpiece. These drilling machines can be bench or floor-mounted. They are driven by an electric motor that turns a drive belt on a motor pulley that connects to the spindle pulley. Hand-feed machines are essentially high-speed machines and are used on small workplaces that require holes 1/2 inch or smaller. Normally, the head can be moved up and down on the column by loosening the locking bolts which allows the drilling machine to drill different heights of work.

Hand feed drilling machines
TOOLS AND EQUIPMENT
TWIST DRILLS Twist drills are the most common cutting tools used with drilling machines. Twist drills are designed to make round holes quickly and accurately in all materials. They are called twist drills mainly because of the helical flutes or grooves that wind around the body from the point to the neck of the drill and appear to be twisted. Twist drills are simply constructed but designed very tough to withstand the high torque of turning, the downward pressure on the drill, and the high heat generated by friction.

Twist drill nomenclature.

TWIST DRILL CONT’D.
There are two common types of twist drills, high-speed steel drills, and carbide-tipped drills. The most common type used for field and maintenance shop work is the high-speed steel twist drill because of its low cost. Carbide-tipped metal drills are used in production work where the drill must remain sharp for extended periods, such as in a numerically controlled drilling machine. Other types of drills available are: carbide tipped masonry drills, solid carbide drills, TIN coated drills, parabolic drills and split point drills.
Twist drills are classified as straight shank or tapered shank. Straight shank twist drills are usually l/2-inch or smaller and tit into geared drill chucks, while tapered shank drills are usually for the larger drills that need more strength which is provided by the taper socket chucks.
Parts of the twist drill. * The Point is the entire conical shaped end of the drill containing the cutting edges and chisel edge. The body is the part of the drill that is fluted and relieved. * The Shank is the part that fits into the holding device, whether it is a straight shank or a tapered shank. The chisel edge is the point at which the two lips meet. * The Chisel Edge acts as a chisel when the drill is turning and cuts into the workpiece. The chisel edge must always be centered exactly on the drill's axis for accurate cutting action.
Common twist drill sizes range from 0.0135 (wire gage size No. 80) to 3.500 inches in diameter. Larger holes are cut by special drills that are not considered as twist drills. The standard sizes used in the United States are the wire gage numbered drills, letter drills, fractional drills, and metric drills (See Table 4-1, in Appendix A). Twist drills can also be classified by the diameter and length of the shank and by the length of the fluted portion of the twist drill.
Wire gage twist drills and letter twist drills are generally used where other than standard fractional sizes are required, such as drilling holes for tapping. In this case, the drilled hole forms the minor diameter of the thread to be cut, and the major diameter which is cut by tapping corresponds to the common fractional size of the screw. Wire gage twist drills range from the smallest to the largest size; from No 80 (0.01 35 inch) to No 1 (0.2280 inch). The larger the number, the smaller the diameter of the drill. Letter size twist drills range from A (0.234 inch) to Z (0.413 inch). As the letters progress, the diameters become larger.
Fractional drills range from 1/64 to 1 3/4 inches in l/64-inch units; from 1/32 to 2 1/4 inches in 1/32-inch units, and from 1/1 6 to 3 1/2 inches in 1/16-inch units.
Metric twist drills are ranged in three ways: miniature set, straight shank, and taper shank. Miniature metric drill sets range from 0.04 mm to 0.99 mm in units of 0.01 mm. * Straight shank metric drills range from 0.05 mm to 20.0 mm in units from 0.02 mm to 0.05 mm depending on the size of the drill. * Taper shank: drills range in size from 8 mm to 80 mm in units from 0.01 mm to 0.05 mm depending on the size of the drill.
The drill gage is used to check the diameter size of a twist drill. The gage consists of a plate having a series of holes. These holes can be numbered, lettered, fractional, or metric-sized twist drills. The cutting end of the drill is placed into the hole to check the size. A micrometer can also be used to check the size of a twist drill by measuring over the margins of the drill. The smaller sizes of drills are not usually marked with the drill size or worn drills may have the drill size rubbed off, thus a drill gage or micrometer must be used to check the size.

OTHER TYPES OF DRILL PRESS DEVICES
COUNTERSINKS
Countersinks are special angled cutters used to countersink holes for flathead screws so they are flush with the surface when mounted. The most common countersinks are cone shaped with angles of 82°. Cone angles of 60°, 90°, 100°, 110°, and 120° are for special needs.
COMBINED COUNTERSINK AND CENTER DRILL
This special drilling tool is used to start holes accurately. These tools are mainly used to center drill and countersink the end of round stock in a lathe machine.
REAMERS
Reamers are cutting tools that are used to enlarge a drilled hole by a few thousandths of an inch for a precise fit.
BORING TOOLS
Boring tools are not usually considered with drilling, but they can be used to bore a hole using the power-feed drilling machines. These tools consist of an arbor with a tool bit attached that cuts a preset sized hole according to the distance that the tool bit protrudes from the arbor.

FIELD EXPEDIENT CUTTERS
Under battlefield conditions, the exact tools may not be available for each job. Simple flat drills can be made quickly from a high-speed steel lathe tool bit or a drill blank. If a grinder is available, then a crude drill can be ground that has a point and two flat edges, which could produce a hole if enough pressure is applied and the workpiece can be machined.
COUNTERBORES
Counter bores are special cutters that use a pilot to guide the cutting action to enlarge a portion of a hole. Common uses are for enlarging a hole to make a bolt head fit flush with the surface.
TAP AND DIE WORK
Hand tapping and hand die work can be done on a drilling machine. The drill chuck is used to align the tap or die.

DRILL HOLDING DEVICES
The revolving vertical spindle of the drilling machine holds and drives the cutting tool. In order to use various sizes and shapes of drills in various machines three types of drill holding devices, which fit the spindle of the drilling machines, are used. They are the geared drill chuck, the drill sleeve, and the drill socket. The larger drilling machines have a spindle that has a standard Morse taper at the bottom end. GEARED DRILL CHUCKS
Drills with straight shanks are held in geared drill chucks which have three adjustable jaws to clamp onto the drill. Smaller size drills are made with straight shanks because of the extra cost of providing these sizes if tapered. Geared drill chucks come in various sizes, with the 3/8 or 1/2-inch capacity chuck being the most common. The shank of the chuck is set into the spindle of the drilling machine by inserting the chuck's shank into the spindle's internal taper and seating the shank into the taper with a light blow with a soft hammer. Both the internal and external taper surfaces must be clean and free of chips for the shank to seat and lock properly. The drill is locked into the chuck by using the chuck key to simultaneously tighten the three chuck jaws. Geared drill chucks can also come with a Morse tapered shank and may have a different method of attaching. They may screw on, have a Jarno taper, or a Jacob's back taper.

Drill holding devices.

WORK HOLDING AND DRILLING DEVICES
Work holding devices are used to hold the work steady for an accurate hole to be drilled, and so a safe drilling operation can be accomplished. Drilling support devices are used to keep the workpiece above the worktable or vise surface and to keep the workpiece aligned for drilling. Some devices are fairly simple and are used for drilling operations that do not require a perfect hole. Other devices are very intricate and designed for more accurate drilling. Many work holding devices are used with one another to produce the most stable work setup for drilling.

Work holding devices.

Work holding devices

MACHINE TABLE VISES
A machine table vise is equipped with jaws which clamp against the workpiece, holding it secure. The vise can be bolted to the drilling table or the tail can be swung around to lay against the column to hold itself steady. Below are listed many types of special purpose machine table vises available to machine operators. * The standard machine table vise is the simplest of all vises. It is equipped with two precision ground jaws for holding onto the work and a lead screw to tighten the one movable jaw to the work. * The swivel vise is a machine vise that has an adjustable base that can swivel through 360° on a horizontal plane. * The angle vise is very similar to the table vise, except this vise can be tilted to 90° to be perpendicular to the work table. * Many other vises are available. These include the compound vise, Universal vise, magnetic vise, and contour vise. V-BLOCKS
V-blocks are precision made blocks with special slots made to anchor clamps that hold workplaces. The V-slot of the block is designed to hold round workplaces. The V-block and clamp set is usually used to hold and drill round stock.
ANGLE PLATES
Angle plates are made in a 900 angle with slots and bolt holes for securing work to the table or to other work holding devices.
JIGS
Drill jigs are devices designed for production drilling jobs. The workplaces are clamped into the jig so that the holes will be drilled in the same location on each piece. The jig may guide the drill through a steel bushing to locate the holes accurately.

DRILLING SUPPORT DEVICES
These devices are important to keep the workpiece parallel while being supported above the worktable or vise surface and to keep the drill from cutting into the holding device or worktable. The following two devices are the most common used.
Blocks are used with clamps to aid in securing and supporting the work. These blocks are usually precision ground of hard steel for long life.
Parallels are precision ground rectangular bars are used to keep the workpiece parallel with the worktable when the workpiece must be raised above the worktable surface, such as when drilling completely through a workpiece. Parallels come in matched sets and can be solid or adjustable as needed.

DRILL SOCKETS AND DRILL SLEEVES Morse taper shank drills come in several sizes, thus, adapters must be used for mounting them into various drilling machine spindles. Drill sleeves and drill sockets are designed to add to or subtract from the Morse taper for fitting a drill into the chuck spindle. For example, it is common for a 3/4 inch twist drill to have a Morse taper of size #2, #3, or #4. It is also common for a drilling machine spindle to have a Morse taper of size #3 or #4, and it can be adapted for many other Morse taper sizes, depending on the size of the drill.
A drill too small for the machine spindle may be fitted into a socket or sleeve which has a taper hole of the proper size to hold the drill and a taper shank of the proper size to fit the drill spindle. Sometimes, more than one socket or sleeve is needed to build up the shank to tit into the drilling machine spindle. Sockets and sleeves may be obtained in a number of different sizes and hole shank taper combinations. Sockets, sleeves, and taper shank drills are mounted into the aligning slots of the spindle and lightly tapped with a soft hammer to seat in place.
DRILL DRIFTS Drill drifts are flat, tapered keys with one rounded edge that are designed to fit into a spindle chuck's slot to force a tapered shank drill loose. The rounded top of the small end of the drill drift is designed to face upward while inserting the drift into the slot. There are two types of drill drifts, the standard type and the safety type.
The standard drift must be inserted into the chuck's slot and then struck with a soft hammer to jar the taper shank drill loose. The drill will fall quickly if not held by the hand and could break or cause injury. The safety drill drift has a sliding hammer weight on the drift itself to allow for a free hand to stay constantly on the drill as it comes loose.

Drift drill

CUTTING FLUIDS
Cutting fluids, lubricants, and coolants are used in drilling work to lubricate the chip being formed for easier removal, to help dissipate the high heat caused by friction, to wash away the chips, to improve the finish, and to permit greater cutting speeds for best efficiency. In drilling work, the cutting fluid can be sprayed, dripped, or machine pumped onto the work and cutting tool to cool the action and provide for maximum tool life. Drilling, reaming, and tapping of various materials can be improved by using the -proper cutting fluids. Cutting fluids can be produced from animal, vegetable, or mineral oils. Some cutting fluids are very versatile and can be used for any operation, while other cutting fluids are specially designed for only one particular metal.

REFERENCES http://www.americanmachinetools.com/lathe_ https://www.classle.net/book/parts-lathe- http://www.efunda.com/processes/machining/turn_tools.cfm http://mmu.ic.polyu.edu.hk/handout/0103/0103.htm machinehttp://www.lathes.co.uk/latheparts/ http://www.smithy.com/machining-handbook/chapter-3/page/21diagram.htm http://www.smithy.com/machining-handbook/chapter-3/page/36 http://www.smithy.com/machining-handbook/chapter-6/page/5