Some of the common metalwork tools used in school workshops are illustrated below. Typical uses are listed beside each illustration.
The steel rule is used for measuring, testing edges for straightness and as a straightedge for marking out.
The engineers square illustrated below is used for drawing lines at right angles to straight edges and testing for squareness.
Scribers are hardened tools which are used to mark lines on the surface of metal.
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The scratch gauge is used to mark lines parallel to the edges of sheetmetal. It is a simple tool, usually made from stainless steel sheet. Gauge sizes are made to standard allowances for seams and edges in sheetmetal working, for example 3mm, 6mm, 5mm and 10mm. |
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Inside calipers are used to measure or test inside diameters and to test edges for being parallel to each other.
Outside calipers are generally used to test and measure outside diameters and sometimes to test straight edges which are a large distance apart, for being parallel to each other.
The illustrations below show the most common types of calipers used in the metal workshop. The spring calipers are set by means of an adjustment nut and screw. The firm joint calipers can be lightly bumped to make fine adjustments to the setting.
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| Spring Calipers | Firm Joint Calipers |
Jenny calipers are marking tools which are used for scribing lines parallel to the edges of the material. Jenny calipers are often called hermaphrodite calipers or odd-leg calipers. The illustration below shows a common type with adjustable point.
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Spring dividers, as shown on the right, are used for scribing circles and arcs and sometimes for drawing lines parallel to the edges of sheet metal. |  |
The engineers hammer or ball pein hammer is mostly used for heavy percussion work such as cutting metal with a cold chisel. It is also used for solid rivetting and sometimes for beating a pattern into art metals.
The cross pein hammer is a general purpose hammer used mainly for lighter work than the engineers hammer. The cross pein can be used in corners that are difficult to work in with the face of the hammer.
The tinman’s mallet is used for bending and shaping metal usually on stakes or mandrels. The mallet is generally used only when the work is too heavy for a dresser.
The dresser is generally made from wood and faced with a material such as red fibre or polyethylene. The dresser is used in sheet-metal working for turning edges and dressing corners.
The pin punch or solid punch is used to make a hole in soft sheet metal when joining with tinman’s rivets and to drive metal pins.
Centre punches are used to make an indentation in the surface of metal to enable a twist drill to enter accurately and sometimes for witness marking. The point angle of a centre punch is 90°.
The prick punch is mainly used to accurately and permanently witness mark centres and lines with a small indentation (prick). The point angle of a prick punch is usually 60°.
The cold chisel is made from steel which is hardened and tempered so that it can be used to cut softer metals. The chisel shown on the right is a typical general purpose flat chisel. Other chisels are made for special purposes such as cutting keyways and grooves.
Combination pliers are general purpose workshop pliers used for bending and cutting wire, gripping small rods and holding thin materials when drilling. Special purpose pliers such as snipe nose pliers and circlip pliers are also used in the workshop.
Lock-grip pliers or vice grips are used as a clamping device in a variety of workshop operations. Holding two or more pieces of thin mild steel together while an aligned hole is drilled through them would be a typical example.
Straight tinsnips are used for straight cutting and large curved cuts in light gauge sheet metal. Bent snips or curved jewellers’ snips are used for cutting tight curves in light gauge sheet metal.
The hacksaw is used for cutting metal bar and rods as well as other materials such as plastics. Hacksaw frames are adjustable to take a number of different blade lengths.
Hack saw blades are available in two varieties. One is soft with hardened teeth and the other is fully hardened. The hard blades wear better, but are brittle and more likely to break. Blades are also available in several lengths, the most common being 300mm.
Hacksaw blades are manufactured with various numbers of teeth per 25mm to suit a range of uses. Common grades are 32, 24 and 18 teeth per 25mm. Generally, a fine blade is used for cutting thin tube, sheet metal and thin sections. Coarser blades are more efficient on solid or thick sections.
Files are used in the workshop for a variety of purposes from rough waste removal to fine finishing of material surfaces. The illustration below shows the two main parts of a file.
The tang of the file is not hardened during manufacture. The tang can be quite sharp and may cause injury to the hand if the file is used without a properly fitted handle.
The body of a file is hard and brittle. This is where the teeth are located. During manufacture the teeth are cut into the body which is then hardened and tempered.
Files may be single cut or double cut. Single cut files have one series of parallel teeth cut at an angle to the centre line of the file. Double cut files have their teeth cut in opposite directions. The grade of a file refers to the coarseness of the cut. The three most common grades are Smooth, Second Cut and Bastard.
Some of the common files used in metalwork and plastics work are shown in the illustrations that follow.
The flat file is a general purpose file that can be used on a wide range of materials. It has double cut teeth on the faces and single cut teeth on both edges. The body is tapered toward the point.
Hand files are also general purpose files that have double cut teeth on the faces. They are parallel files with single cut teeth on one edge only. The edge without teeth is called the safe edge.
Half-round files have one flat face and a curved back. Like the hand file the shape of the body tapers toward the point. Half round files are used to file round holes and concave curves.
Round files or rat-tail files are generally used for enlarging holes and filing concave surfaces.
Triangular files are used for filing internal corners between the angles of 60° and 90°. Small triangular slim taper files are often called saw files. They are used for sharpening handsaws.
Warding files are used for filing narrow slots or notches and for working in confined spaces.
A file brush which has stiff wire bristles should be used to clean waste material out of the file teeth. The file brush should be used only in the direction of the file teeth to avoid unnecessary wear of both the file teeth and the brush.
Taps are hardened tools used for cutting internal screw threads. The illustrations below show the three types of taps required to tap a blind hole. A blind hole is not drilled all the way through the material.
The taper tap is used to start the thread. The teeth are ground back to a long taper to make the cut easier to start.
The taper tap would also be used to thread a hole that goes all the way through thinner material.
The intermediate tap is used after the thread has been started with the taper tap. As shown in the illustration, the intermediate tap has a shorter taper than the taper tap.
The bottoming tap is commonly called a plug tap and is used to finish the thread in a blind hole.
A tap wrench is used to hold the tap and provide the rotational power which is necessary for the threading operation. A bar type tap wrench is illustrated below.
A suitable cutting oil should always be used during tapping operations. When tapping a thread care must be taken to back off the cutting action every half turn or so. This reverse action breaks off the waste material.
Taps are very hard and therefore very brittle, hence they will break if too much pressure is applied particularly if the waste material is allowed to build up.
The tapping hole must be smaller than the outside diameter of the tap so the teeth of the tap can cut into the metal. For most metric threads the size of the tapping hole can be found using the following simple formula:
Tapping Hole = D − p
D is the outside diameter of the tap and p is the pitch. Pitch is the distance between threads.
Button dies are hardened tools which have a threaded hole that cuts external screw threads on round bar.
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Most button dies have the diameter and pitch of the thread stamped on them, for example 4.5mm x 0.60mm. This means that the outside diameter of the thread is 4.5mm and the pitch of the thread is 0.60mm. |
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A die stock, often called a die holder, is used to hold the button die.
A small bevel should be filed on the end of the metal rod to be threaded. This will help the thread to start as the die stock is rotated. Cutting oil should be used and the cutting action backed off every half turn or so to break off the waste.
Before leaving this page, think of what you've just been reading, and test yourself with these questions.
[[ mm /f ][ Match the measuring tool with the task: ][ Inside calipers ~ measure inside diameters ][ Outside calipers ~ measure outside diameters ][ Jenny calipers ~ scribing lines parallel to edges ][ Spring dividers ~ scribing circles and arcs ][ Inside calipers = measure inside diameters; Outside calipers = measure outside diameters; Jenny calipers = scribing lines parallel to edges; Spring dividers ~ scribing circles and arcs. ]]
[[ mm /f ][ Match the hammering tool with the task: ][ Ball pein hammer ~ for heavy hitting ][ Cross pein hammer ~ can be used in corners ][ Tinman’s mallet ~ shaping metal on stakes ][ Dresser ~ for turning edges ][ Ball pein hammer - for heavy hitting; Cross pein hammer - can be used in corners; Tinman’s mallet - shaping metal on stakes; Dresser - for turning edges. ]]
[[ mm /f ][ Match the punch or chisel with the task: ][ Pin punch ~ to make a hole in soft sheet metal ][ Centre punch ~ to make an indentation on the surface of metal ][ Prick punch ~ to witness mark centres and lines ][ Cold chisel ~ to cut softer metals ][ Pin punch - to make a hole in soft sheet metal; Centre punch - to make an indentation on the surface of metal; Prick punch - to witness mark centres and lines; Cold chisel - to cut softer metals ]]
[[ mm /f ][ Match the pliers and/or snips with the task: ][ Combination pliers ~ for bending and cutting wire ][ Lock-grip pliers ~ are used as a clamping device ][ Straight snips ~ for straight cutting and large curved cuts ][ Bent snips ~ are used for cutting tight curves ][ Combination pliers - for bending and cutting wire; Lock-grip pliers - are used as a clamping device; Straight snips - for straight cutting and large curved cuts; Bent snips - are used for cutting tight curves ]]
[[ mm /f ][ Match the file with the task / description: ][ Flat files ~ are tapered toward the point ][ Hand files ~ are parallel files with single cut teeth on one edge only ][ Half-round files ~ have one flat face and a curved back ][ Rat-tail files ~ are used for enlarging holes ][ Triangular files ~ are used for filing internal corners ][ Flat files - are tapered toward the point; Hand files - are parallel files with single cut teeth on one edge only; Half-round files - have one flat face and a curved back; Rat-tail files - are used for enlarging holes; Triangular files - are used for filing internal corners. ]]
[[ mm /f ][ Match the tap with the description / task ][ Taper tap ~ is used to start the thread ][ Intermediate tap ~ has a shorter taper than the taper tap ][ Bottoming tap ~ is used to finish the thread ][ Plug tap ~ is another name for the bottoming tap ][ Taper tap - is used to start the thread; Intermediate tap - has a shorter taper than the taper tap; Bottoming tap - is used to finish the thread; Plug tap - is another name for the bottoming tap. ]]
[[ sh ][ METALWORK STAKES ]]The illustrations which follow show some of the stakes and mandrels which are used for bending and shaping light gauge sheet metal. Metalwork stakes usually have a tapered shank which is fitted and sometimes bolted to a stake bench.
Stakes are usually manufactured from mild steel which is quite soft and easy to damage. Hammers should not be used to bend or shape sheet metal on these stakes. Some processes require the use of a mallet but generally a dresser is satisfactory for most soft sheet metals.
Before leaving this page, think of what you've just been reading, and test yourself with these questions.
[[ mr /f ][ What type of metalworking tools should be used for working sheet metal on any of these stakes or mandrels? ][ * Ball pein hammer ][ Mallet ][ Dresser ][ * Cross pein hammer ][ Timber mallets and dressers should be used for this type of work. ]]
[[ sh ][ PORTABLE POWER TOOLS ]]Portable drills are available in a wide range of types and sizes with a number of different features including dual and variable speeds, forward and reverse, torque settings and impact or hammer function.
The drill bit is held in a chuck which is connected by a shaft and gear arrangement to an electric motor. Most portable electric drills are equipped with a switch lock. Generally, students are advised to use the switch lock only when the drill is fixed in a drill stand.
Basic drills are light and compact, usually featuring variable speed and reverse. Chuck size is usually 6.5mm or 10mm.
Cordless drills feature a rechargeable battery and are usually equipped with a 10mm or 13mm chuck. Other features may include dual or variable speeds, multiple torque settings, forward and reverse. These features combine to make most cordless drills suitable for both drilling and screwdriving operations.
Impact drills are usually powerful multi-purpose drills which have extra features such as a two speed gearbox, variable speed reversible, usually with a 13mm geared chuck. The model illustrated on the right also has an adjustable depth guide fitted.
The impact or hammer mode is engaged by pressing the button provided. This feature is generally used for drilling into masonry or brickwork.
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| Basic Drill | Cordless Drill | Impact Drill |
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The drill stand shown on the right is designed to be bolted to a workbench and will take any portable drill with a collar diameter of 43mm. The base plate is slotted so that a machine vice or workpiece can be bolted down or otherwise fixed in position for maximum accuracy in drilling operations. The switch lock on the drill can be engaged when the tool is used in this way. |
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Angle grinders are mostly used for rapid removal of material. They are fitted with grinding discs or wheels that are available in a range of grades for finer or coarser work. The photograph below shows a typical small angle grinder suitable for general purpose use in the metal workshop.
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The forward handles on these tools are interchangeable for both right and left hand operation. Angle grinders are so named because the shaft which drives the abrasive disc is at an angle, usually 90°, to the motor shaft. This arrangement allows the operator to comfortably apply pressure to the flat of the abrasive disc during grinding operations. |
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Nibblers cut a slot in a continuous punching action. With each stroke a piece of material (slug) is removed as the nibbler is fed into the work. This cutting action makes the nibbler highly manoeuvrable. It is particularly suitable for cutting shapes with tight curves or corners. |
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The jigsaw is a versatile tool which can be used for a variety of cutting operations on most sheet materials including metal. It can be used for straight cutting but is most useful for cutting shapes which involve tight curves. The jigsaw shown on the right has a variable speed feature which allows the operator to use the cutting speed most suited to the job by varying the pressure on the trigger switch. |
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Before leaving this page, think of what you've just been reading, and test yourself with these questions.
[[ mc /f ][ What type of drill would usually be used for drilling into masonry? ][ Impact drill ][ * Cordless drill ][ * Basic drill ][ Impact drills have a hammer mechanism built-in. ]]
[[ mc /f ][ Why are angle grinders so called? ][ The grinding disc is at a 90° angle to the motor shaft ][ * You can hold the grinder at any angle ][ * The disc angle is adjustable ][ * The disc face is at a slight angle ][ The grinding disc rotates at 90° to the motor shaft. ]]
[[ mr /f ][ Which of these are reasonable safety precautions when working with portable power tools? ][ Do not walk on flexible cords ][ Do not use blunt or damaged blades ][ Never operate in wet or damp conditions ][ * Loosen your clothing ][ * Don't use earmuffs ][ Check your answers if you've don't get these correct. ]]
[[ sh ][ THE METAL LATHE ]]The lathe is a workshop machine that is designed to support and rotate a piece of material as it is being shaped by a cutting tool. The lathe is capable of producing cylindrical, conical, helical and spherical shapes that are co-axial with the centre line of the lathe. This type is often referred to as a centre lathe.
Small machines are usually mounted on a bench or a stand and are sometimes called bench lathes. Bench lathes are available in various sizes, capable of turning lengths between about 600mm and 1000mm.
There are two main types of centre lathe. Lathes in which turning speeds are varied by means of step-cone pulleys are belt driven and are usually called belt-drive head lathes. Lathes that are driven through a gear box are usually called geared head lathes. The drive mechanism of a lathe is contained within the headstock as shown in the illustrations which follow.
The photograph below shows a small bench lathe which has a belt-drive head. The main parts indicated in the illustration are common to most lathes.
The photograph below shows a typical geared head bench lathe. Except for the drive mechanism, the main parts of the geared head lathe are basically the same as the belt driven lathe.
The headstock is positioned at the left hand end of the lathe bed and can be of the cone pulley or fully geared type. The main spindle (shaft) is mounted in bearings in the headstock. These bearings must be capable of withstanding the heavy loads imposed by the turning operations and also capable of maintaining the accuracy required in the finished job.
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Belt Drive: On a belt driven lathe spindle speed is changed by shifting the belt to a different pair of pulleys. Belt driven lathes also have a reduction unit in the headstock assembly. This reduction unit is called back gear which is engaged for knurling operations where a very slow turning speed is required. Back gear is engaged using the back gear lever shown in the upper illustration on the right which also shows the step cone pulleys, drive belt and the gear train which connects the headstock spindle to the lead screw. |  |
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Geared Head: On most geared head lathes spindle speeds are selected by simply moving gear levers. The lower illustration on the right shows a simple configuration of gears in a geared headstock. This arrangement allows a number of different gear ratios to be selected providing a range of spindle speeds. |
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The tailstock is comprised of two castings. One rests on the ways and may be clamped to the bed in any position to accommodate work of varying lengths. The tailstock spindle or quill is housed in the upper casting which has a sideways adjustment. The tailstock spindle is bored to a standard morse taper to take centres, drill chucks and other attachments.
The carriage is the part of the lathe that supports and controls the movement of the cutting tool. The carriage is comprised of the saddle which fits over and slides on the ways of the lathe and the apron which is fastened to the saddle and hangs in front of the lathe bed. The apron carries the handwheel mechanism for hand feed as well as the mechanisms for engaging automatic feed and the lead screw.
A dovetail way machined in the saddle at 90° to the axis of the lathe carries the cross slide which allows cross feed of the cutting tool. The cross slide is operated by a handwheel and is fitted with a graduated collar so the depth of the cut can be accurately read. When parallel turning, a movement of 1mm in the cross slide will reduce the turned diameter of the work by 2mm.
The compound slide rest is mounted on top of the cross slide and has a swivel base that can move through 360°. The base can be locked in any position denoted by graduations from 0° to 180°. A dovetail way allows the compound slide which holds the tool post to be moved by a screw feed. The compound slide is also fitted with a graduated collar to control the depth of the cut when facing the work.
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The tool post is a device for firmly clamping the cutting tool or tool holder on to the lathe. The tool post is fitted to the top of the compound slide. The photograph on the right shows a standard tool post. Standard tool posts are sometimes called American style tool posts. |
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The photograph on the right shows a square tool post with a cutting tool and tool holder mounted. The square tool post is capable of holding multiple lathe tools. The main advantage of the square tool post is that they can be quickly rotated into a new position when it is necessary to change the tool for the next stage of the work. |
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The headstock and tailstock spindles are bored out to a standard morse taper to receive the headstock and tailstock centres whose shanks are also morse tapers. The points are turned or ground to an angle of 60° to fit the countersink section of a centre drill. Plain and live centres are illustrated below.
Plain centres can be used in both the headstock and tailstock. A plain centre used in the tailstock is often called a dead centre because it does not rotate. The bearing surface of a dead centre must be hardened and well lubricated to resist wear.
Live centres are used in the tailstock and are constructed with ball or roller bearings which enable the point of the centre to rotate with the work.
Centre drills are used to bore the end of the workpiece to provide an accurate bearing surface for the centre.
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Tool holders for high speed steel cutting tools are available in straight, right hand and left hand styles as illustrated on the right. The left hand tool holder is used when machining is required close to the headstock. The straight tool holder is used for general purpose machining and for screw cutting on the lathe. The right hand tool holder is usually used for facing operations and for turning work close to the tailstock. |
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There are numerous other types of tool holders for special turning operations such as parting and a range of indexable tip holders which are used to hold tungsten carbide turning inserts or tips. Typical examples are illustrated below.
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| Parting Tool And Holder | Indexable Tip And Holder |
Lathe tools may be described as right or left hand according to the direction of travel when making a cut. Right hand turning tools are fed from right to left and left hand tools are fed from left to right.
Some general purpose tools are ground to cut efficiently in either direction.
Rough turning tools, as illustrated below left, are used to reduce the work close to the finished size.
Finishing tools are used to reduce the work to the finished size and to provide a good finish. The illustration below right shows a right hand finishing tool.
The straight round nose tool shown below, lower left, is a general purpose tool which can make light cuts in either direction. It can also be used as a finishing tool.
The facing tool illustrated below, lower right, is used to square ends of the job or turn shoulders. The facing tool is usually ground to a reasonably sharp point which is intended to take light cuts only.
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| Rough Turning Tool | Finishing Tool |
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| Straight Round Nose Tool | Facing Tool |
Knurling is not a cutting process. The knurling tool, under pressure, actually displaces metal in the formation of a diamond shape or straight line pattern pressed into the surface of the work. The knurling rollers are cylinders of high grade tool steel which have formed teeth cut in their circumference.
Knurling is performed at very low speed.
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| Knurling Tool | Knurling |
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The three jaw chuck is self centring. It is constructed so that the three jaws all move together and are always the same distance from the centre. The three jaw self centring chuck is used to hold round and hexagonal work. Chucks that have jaws which can be moved independently are used to hold square and rectangular work. |
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All lathe tools should be positioned with the cutting edge at the same height as the centre line of the lathe, as shown in the illustration on the right. When a square tool post is being used, the lathe tool can be adjusted to the correct height by placing strips of packing such as thin sheet metal, under the tool holder. |
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Students should use the metal lathe only when:
Permission is granted by the teacher.
Adequate instruction in the safe and proper use of the machine has been received.
Before leaving this page, think of what you've just been reading, and test yourself with these questions.
[[ mc /f ][ Where will you find the drive belts on a typical lathe? ][ The headstock ][ * The tailstock ][ * The saddle ][ * The apron ][ The drive belts are contained within the headstock. ]]
[[ mr /f ][ What are you likely to find fitted into the tailstock of the lathe? ][ A plain centre ][ A live centre ][ A centre drill ][ * A tool post ][ * A cutting tool ][ The tailstock can hold centres or drills. ]]
[[mm /f ][ Match the cutting tool to its typical use: ][ Rough turning tool ~ used to reduce the work close to the finished size ][ Finishing tool ~ used to provide a good finish ][ Straight round-nose tool ~ make light cuts in either direction ][ Facing tool ~ to square ends of the job ][ Rough turning tool - used to reduce the work; Finishing tool - used to provide a good finish; Straight round-nose tool - make light cuts in either direction; Facing tool - to square ends of the job ]]
[[ mr /f ][ What shape of work can be held by a 3-jaw self-centring chuck? ][ Round work ][ Hexagonal work ][ * Square work ][ * Rectangular work ][ 3-jaw chucks are best for round or hexagonal work. ]]
[[ mr /f ][ Which of the following are recommended safety practices for working on and around lathes: ][ Do not leave tools on the saddle ][ Always remove burrs from the workpiece ][ * Clean the lathe only when its running ][ Remove the chuck key immediately after use ][ * Always use compressed air to clean the lathe ][ Check the safety practices for how to clean a lathe. ]]
[[ sh ][ THE DRILLING MACHINE ]]|
The photograph on the right shows the major parts of a typical drilling machine or drill press. Drilling is the process of machining round holes in any solid material using end cutting tools called drills. A typical twist drill is also illustrated on the next page. The drill is held in a chuck similar to the chucks used on portable electric drills and hand drills. The drilling machine provides the rotary motion and the pressure required to cause the cutting edges of the twist drill to penetrate the material being drilled. The drill type type shown is a floor mounted, belt driven column drill. A similar machine with a shorter column would be mounted on a bench. Bench drills are sometimes called pedestal drills. |
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Belt Drive: Drilling machines that are belt driven are fitted with cone pulleys to provide a range of drill speeds from a few hundred revolutions per minute to a few thousand revolutions per minute. Speed should be varied according to the work being done and the size of the twist drill being used. Generally a large drill requires a slower speed and a small drill requires a faster speed. V-belts and pulleys transfer rotary motion and power from the motor to the drill spindle. Drill speeds are varied by changing the position of the belts on the cone pulleys. A large pulley driving a small one gives a faster speed and a small pulley driving a large one gives a slower speed. The illustration on the right shows a typical belt and pulley arrangement which provides a range of drill speeds. |
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Gear Drive: Geared head drilling machines usually have a motor mounted directly on a gearbox which provides the range of drill speeds. Speeds are changed by moving gear levers on the side of the gearbox. A typical geared head column drill is shown in the photograph on the right. Apart from the drive mechanism, the construction and usage of this drill is similar to the belt driven machine shown on the previous page. |
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Twist drills are usually made from high carbon steel or high speed steel. Good quality twist drills will usually be stamped HS for ‘high speed’ indicating that they are made from high speed steel.
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The shank of the twist drill is the part which is held in the chuck. Straight shank drills are the ones most commonly used while reduced shank drills enable larger sizes to be fitted in a standard chuck. Flutes are the spiral grooves in the twist drill which provide a channel for the outlet of the waste. The lands are the precision ground surfaces on the leading edges of the flutes. The lands have a slightly larger diameter than the diameter of the body clearance surfaces. The heel is the trailing edge of the body clearance surface. The point angle of a high speed twist drill is usually ground to 118°. This is satisfactory for most drilling operations. The point angle is sometimes reduced for softer materials. |
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A machine vice is generally used to hold flat work. A modern mechanical-hydraulic machine vice is shown on the right. When used with small drills and where a great deal of accuracy is not required, the machine vice may be held by hand. |
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Where very accurate drilling is necessary the machine vice should be bolted to the drilling machine table. Parallel packing strips should be used to ensure that the drill does not damage the machine vice. The illustration on the left shows a mechanical machine vice bolted to the drilling machine table with packing strips supporting the work. |  |
A hand vice or vice grip pliers should always be used when drilling short pieces of thin material.
Holding short pieces of material in the hand can lead to serious injury if the drill sticks and causes the operator’s grip to release allowing the work to rotate at a very fast speed with the twist drill.
When work is gripped by a hand held device it should generally be supported by a piece of wood on the drilling machine table.
Students should use the drilling machine only when:
Before leaving this page, think of what you've just been reading, and test yourself with these questions.
[[ mc /f ][ How should you select the drive belt pulleys when drilling with a large drill size? ][ Small driving pulley, large driven pulley ][ * Large driving pulley, small driven pulley ][ * Small driving pulley, small driven pulley ][ * Large driving pulley, large driven pulley ][ Large drills need to turn slowly, so a large driven pulley is needed. ]]
[[ mc /f ][ How should short pieces of thin material be held when drilling? ][ * With a leather safety glove ][ With vice-grip pliers ][ * With a machine vice ][ * With a pair of pliers ][ Vice-grip pliers or a hand vice is the preferred way to hold this type of work. ]]
[[ mr /f ][ Which of these are reasonable safe operating practices? ][ Check that the drill is correctly fitted in the chuck ][ Secure the work adequately ][ Make sure all guards are in place ][ * Remove swarf with your hands ][ * Make adjustments while the drill is running ][ Swarf is sharp, so don't handle it; switch the drill off before adjusting. ]]