BASIC HAND AND POWER TOOLS
Hammers are striking tools that are made of two basic parts: the head and handle. Hammers drive and remove nails, drive stakes, shape metal, and break rock and concrete.
Before using any type of hammer, inspect it thoroughly for conditions that may cause bodily injury or damage to the hammer during use. Inspect the hammer handle to make sure there are no splits, cracks, or splinters that may cause it to break. Replacement of the handle may be necessary. Check the condition of the hammer head to make sure it is not chipped or damaged. Check the condition of the head to handle fit. The head should fit tightly on the handle so it will not come off when swinging the hammer.
The proper care of hammers includes wiping the metal surfaces with a lightly oiled cloth to prevent corrosion. Broken or splintered handles must be replaced. A grinding wheel is used to dress the head if it is damaged.
The proper use of any hammer requires three things: a good grip, the proper swing, and an accurate swing. Also, always wear goggles or a protective face shield when using a hammer.
To grip the hammer correctly, place the handle flat against the palm of the hand with the fingers wrapped around the handle close to the base (see Figure 1). Gripping the hammer close to the base increases striking power since this allows the hammer to be used as an extension of the arm.
Figure 1: Proper Hammer Grip
Remember that the length of the hammer’s swing is directly proportional to the amount of force needed to do the job. For example, driving a small nail into a thin piece of wood requires a short swing, while breaking a block of concrete requires a long swing.
To ensure the proper strike, place the head of the hammer on the target to get the correct feel and set. Then, swing the hammer up a distance that will produce the proper amount of force. Bring the hammer down with a quick, even stroke to hit the target squarely with the hammer face (see Figure 2).
Figure 2: Proper Hammer Strike
Now let’s look at the four most common types of hammers: the machinist’s, or ball peen, hammer; the carpenter’s hammer; the sledge hammer; and the chipping hammer. Each of these hammers is readily identifiable by the shape of its head.
A machinist’s, or ball peen, hammer has a rounded striking face and a ball-shaped peen (Figure 3). Ball peen hammers are classified according to the weight of their head, which generally ranges from 2 ounces to 4 pounds.
Figure 3: Ball Peen Hammer
The inspection of ball peen hammers is the same as for hammers in general. An additional inspection is made of the head for mushroomed edges.
When driving rivets or metal pins, hold the rivet or pin in your free hand. Tap the rivet or pin lightly to get it started and make it stand without holding it. Strike the rivet or pin squarely with the peen end of the hammer. When striking chisels, punches, or other metal working tools, position the chisel or punch on the work and strike squarely with the face of the hammer.
A carpenter’s hammer has a slightly rounded striking face and a claw on the side opposite the face (Figure 4). Carpenter’s hammers are classified by weight and the type of claw.
Figure 4: Carpenter’s Hammer
A carpenter’s hammer is used for carpentry work, including construction of barricades, sheeting and shoring excavations, and other general-purpose wood construction.
When driving nails, be sure to select the proper hammer size for the job. Hold the nail upright with the thumb and forefinger of the free hand. Next, tap the nail gently so that the tip enters the work far enough to allow the nail to stand alone. Then, strike the nail squarely with the face of the hammer, i.e., the center of the face should hit the head of the nail. Hitting the nail at an angle can cause it to bend or chip the face of the hammer.
When removing partially exposed nails, the point of the nail is tapped to raise the head above the surface of the work. The head of the nail is then positioned between the legs of the claws (on finished work, a rag or pad is placed under the hammer to prevent damage to the surface). The handle is then pulled away from the nail to produce a lever action.
A sledge hammer is a heavy-duty striking tool with a slightly rounded striking face on each end (Figure 5). Sledge hammers may have short or long handles, with heads weighing up to 20 pounds. Sledge hammers are used to drive bolts, drift pins, or metal stakes; hit cold chisels and masonry drills; and break up concrete or rocks.
Figure 5: Sledge Hammers
When using a short-handled sledge hammer, the grip is the same as with a regular hammer. The target is struck squarely with short, quick strokes.
When using a long-handled sledge hammer, two hands are used to grip the hammer near the base. Place your feet comfortably apart and at a distance from the target that allows contact of the hammer head with the target when the hammer is held with the arms fully extended. After clearance for the proper swing is ensured, raise the hammer above the shoulder. At the top of the swing, a right-handed person will have the left hand at the base of the hammer, and vice versa for a left-handed person. The other hand is positioned near the head of the hammer to control the weight of the hammer and the strike. Swing the hammer downward while sliding the hand near the head of the hammer down to the base to help guide the swing; thus, both hands will be at the base of the hammer at the moment of contact.
A chipping hammer has a blade-type striking surface on one end and a spike point on the opposite end (see Figure 6). A chipping hammer is mainly used to remove slag from welds and to remove concrete from metal surfaces.
Figure 6: Chipping Hammers
Chipping hammer inspection is the same as for hammers in general. In addition, inspect the blade to ensure that it is sharp and not chipped or damaged.
When using a chipping hammer, the work must be properly secured. The chipping hammer is gripped like a normal hammer. The hammer is swung so that the blade strikes the work at a slight angle.
Wrenches help the user exert the rotational force needed to tighten or loosen threaded fasteners, i.e., nuts, bolts, studs, and threaded pipe fixtures. Wrenches are designated by the size of the opening between the jaws. The wrench opening is manufactured slightly larger than the bolt head or nut that it is designed to fit. This clearance allows the wrench to slide on and off the nut or bolt with a minimum of play between the jaws of the wrench and the nut. If the wrench is too large, the points of the bolt head will become rounded off, causing the wrench to slip.
The methods for the correct and safe use of wrenches in general are outlined below.
In this section, numerous types of wrenches are described, and procedures for their use are outlined.
An open-end wrench has a head that is open on one side. Open-end wrenches may have their jaws parallel to the handle or at angles of up to 90 degrees. The normal angle is 15 degrees. The angle of the head allows the wrench to fit and turn a bolt in a confined space by alternately flipping the wrench over after each arc of rotation, allowing the wrench to grip the next flat on the bolt head or nut. Wrench handles are normally straight, but they may be curved to reach nuts or bolt heads below an adjoining surface. Refer to Figure 7.
Figure 7: Types of Open-End Wrenches
Open-end wrenches are used to remove or tighten fasteners. Construction, or spud, wrenches are used to line up holes, such as bolt holes in flanges. Crowfoot wrenches are used to tighten or loosen fasteners in places that are difficult to reach, such as bolts in engine blocks. Inspect all open-end wrenches prior to use. Examine the jaws and handle to ensure that they are not damaged.
When using an open-end wrench, select the proper sized wrench for the particular job. Place the jaws of the wrench around the fastener so that they fit snugly. Then, pull the handle of the wrench to loosen or tighten the fastener. Pushing the wrench can cause it to slip and injure your hand. If the wrench must be pushed, it is done with an open hand so that if the wrench slips, it will hit the equipment, not your hand. The wrench may need to be repositioned to allow the needed clearance to complete the work, i.e., the wrench may be flipped over or removed from the work to reset it.
Except in the case of a slugging wrench, never strike a wrench with a hammer. A pipe or a cheater bar is never used to increase the leverage on a wrench. Wrenches should be cleaned after each use with a lightly oiled rag to prevent corrosion. Wrenches are stored in a tool box away from other tools or hung on wall racks.
Box-end wrenches have a closed head that is designed to completely surround the fastener (see Figure 8). It is stronger than an open-end wrench and less likely to slip off the fastener. The inside surface of the head is lined with a series of points, ranging from six to sixteen in number depending on the size of the wrench head. Wrenches with 6-point heads are designed for heavy work and wrenches with 12-point heads are designed for medium work. The points enable the wrench to grip the fastener from almost any angle.
Figure 8: Box-End Wrench
Box-end wrenches have the same uses as open-end wrenches, but are more adaptable to hard-to-reach areas. During use, the wrench must be lifted off the fastener each time the grip is changed. The head of the box-end wrench should be inspected to make sure that the points are not worn or damaged.
Combination wrenches have a box end and an open end on the same handle (Figure 9). Both ends fit the same size fastener.
Figure 9: Combination Wrench
Combination wrenches are used to remove or tighten fasteners. Always inspect the heads of a combination wrench for wear and damage. During use, the wrench must be lifted off the fastener each time the grip is changed. It is not necessary to flip the wrench over to change the angle in relation to the fastener.
A socket wrench set contains an assortment of individual sockets and other accessories made to fit different sized fasteners. The ratchet handle and sockets can be assembled to allow various wrenching jobs to be done quickly and easily. Refer to Figure 10.
The square on the drive end of the ratchet or hinged handle designates its size. The ratchet handle is reversible. The direction of movement is changed by changing the position of the reversing switch on the back of the ratchet head opposite the socket drive. This allows the worker to both tighten and loosen a nut or bolt in a rapid fashion without removing the socket from the fastener.
The nut opening of the socket usually has 6, 8, or 12 points, similar to the box-end wrench. Sockets with thin walls are available for use in extremely close quarters. The end of the socket opposite the nut opening has a square hole for the socket drive or attachment. It is always a good idea to check the condition of the handle, lug, and socket teeth prior to use.
Figure 10: Socket Wrenches
The ratchet, socket, and other handles initially chosen break the fasteners free and spin them off quickly in work areas with plenty of space. Then, the proper size socket is chosen and locked onto the socket drive. The wrench is then checked for proper rotation to loosen or tighten. Finally, the socket is placed over the nut or bolt and loosened or tightened. When the handle cannot be moved any further in the direction desired, return the handle to the original starting position to allow further loosening or tightening of the fastener. The socket wrench should click as it slips on the internal clutch while the socket remains stationary.
Adjustable wrenches are handy, general-purpose wrenches, but they are not intended to take the place of the regular open-end wrench for steady, hard service. One jaw of the adjustable open-end wrench is fixed, while the other jaw is moved along a slide by an adjusting screw. Refer to Figure 11.
Figure 11: Adjustable Wrenches
The adjustable wrench loosens or tightens oddly sized fasteners that a regular open- or box-end wrench will not fit. An adjustable wrench is not used if an open- or box-end wrench will do the job.
Check the condition of the handle and jaw working surfaces before use. Inspect the screw adjusting device for looseness or play. The adjustable jaw should move smoothly when the screw device is turned, with no looseness or play once a setting is selected.
Adjust the jaws so that they are snug against the sides of the fastener. When using, always pull the wrench in the direction of the movable jaw so that pressure is put on the fixed jaw.
Adjustable wrenches require the same care as open-end wrenches.
Pipe wrenches have a hook-shaped movable jaw and a fixed jaw. The movable jaw is adjusted by turning a nut, which is attached to the handle. The jaws are spring-loaded to allow them to spread slightly when put on the pipe and tighten when pressure is applied to the handle. The jaws have serrated teeth to grip smooth surfaces. Hook-jaw pipe wrenches may be straight or offset. Refer to Figure 12.
Figure 12: Hook-Jaw Pipe Wrenches
Place the wrench on the pipe so that only the centers of the jaws touch the pipe. Pull the wrench in the direction away from the fixed jaw. Hook-jaw pipe wrenches are designed to loosen or tighten threaded pipes or pipe fixtures.
Before use, check the handle and the teeth on the jaws to ensure they are in good condition. Also, inspect the adjusting nut for looseness or play.
Flexible-member pipe wrenches have a chain or strap attached to the handle instead of a hooked jaw. Refer to Figure 13.
Figure 13: Flexible-Member Pipe Wrenches
Flexible-member pipe wrenches fit over pipes that are too large or difficult to grip with a conventional pipe wrench. The strap-type wrench is designed to be used on pipes made of plastic or finished material, which could be damaged by the hooked jaws of a conventional pipe wrench or the chain on a flexible-member pipe wrench.
Before use, check the chain or strap to make sure it is not damaged and is securely fastened to the handle.
Place the chain or strap around the work and hook the free end into the frame of the wrench. Then, pull the handle toward the body to exert force. Lastly, swing the handle in the opposite direction at the end of each partial turn to obtain a new grip.
Internal pipe wrenches have a set of knurled eccentric wheels that expand or contract when the handle is moved. Refer to Figure 14.
Figure 14: Internal Pipe Wrench
The internal pipe wrench is used to loosen or tighten threaded pipes, closed nipples, and threaded pipe fixtures.
Before use, inspect the wheels for wear or damage. The wheels must turn smoothly when the handle is moved. Insert the wrench into the end of the pipe. Attach the handle to the wrench. Turn the handle clockwise or counter-clockwise to expand the wheels so that they grip the inside surface of the pipe. Turn the handle about one-quarter turn in the opposite direction to loosen the wrench from the pipe.
Spanner wrenches are specifically designed to tighten or loosen spanner fasteners. There are two types of spanner wrenches: the hook, or lug, type, which has either a hook or a lug at the end of the handle that is designed to fit the holes in the fastener; and the pin type, which has pins instead of a lug or a hook at the end of handle. Both of these types of spanners may be of the fixed, adjustable, face, or socket style. Refer to Figure 15.
Spanner wrenches are used to tighten or loosen spanner fasteners, which are special nuts with notches or holes in their side or end surfaces. Before use, inspect the lug, hook, or pin to make sure that it is not worn or damaged. Also, inspect the joint on adjustable spanners to make sure that it moves smoothly but does not have too much play or looseness.
Figure 15: Hook and Pin Spanner Wrenches
The proper type of spanner wrench must be selected for the job. When using a fixed, adjustable, or face-type spanner wrench, insert the hook, lug, or pin into the notches on the surface of the fastener so that the heel of the wrench rests against the surface of the nut. Then, pull the handle toward the body (see Figure 16).
Figure 16: Using a Spanner Wrench
When using a socket spanner wrench, place the socket onto the sliding bar handle. Insert the wrench into the notches along the edge of the fastener and twist the handle (see Figure 17).
Figure 17: Socket Spanner Wrench
Internal hex wrenches are L-shaped headless wrenches cut from hexagonal stock or round stock. The socket-head fasteners usually are Allen (hexagonal) or Bristol screws (Figure 18).
Figure 18: Internal Hex Wrench
Internal hex wrenches are designed to loosen or tighten set screws, cap screws, or socket-head fasteners. Before using, inspect the ends of the wrench for damage. The multi-splines must not be broken or bent, and hexagonal surfaces must not be damaged.
Fit the wrench snugly into the socket opening of the fastener (either end of the wrench may be used). Pull the handle to loosen or tighten the fastener.
Slugging wrenches are box-end wrenches with short, sturdy handles. A steel pad section is provided on the handle for hammer blows. Refer to Figure 19.
Figure 19: Slugging Wrench
Slugging wrenches are designed to be hammered on to break fasteners loose that cannot be removed with a conventional wrench.
Before using, inspect the handle and head for wear and damage. Safety goggles or a face shield are always worn when using a slugging wrench. Place a tag line on the wrench when striking it with a sledgehammer. Attach the wrench to the fastener. Strike the end of the wrench with the hammer being used to loosen or tighten the fastener.
Torque is simply a turning or twisting force. A torque reading is a measure of the effectiveness of that force. A torque wrench measures that force.
A torque wrench is a special wrench in that it acts as both a wrench and a measuring tool. During use, it applies a twisting force like a conventional wrench while simultaneously measuring the amount of force that is being applied. There are three different types of torque wrenches:
Figure 20: Beam-Type Torque Wrench
Figure 21: Micrometer-Type Torque Wrench
Figure 22: Dial-Type Torque Wrench
Inspect torque wrenches for general damage prior to use, paying particular attention to the beam. Check the socket lug. It should be a well-formed square with the locking button in place. In addition, check the calibration tag to ensure that the wrench is not in need of recalibration. It is a requirement that torque wrenches be calibrated on a yearly basis.
Check the fastener to be torqued or get the correct torque value for the fastener from a chart or from manufacturer’s literature for the equipment. Torque the fastener by pulling on the handle in a smooth motion until the indicator reaches the required torque value. Ratchet-type torque wrenches work the same as the beam-type except that they click when the required torque is reached. Pull on the handle with a smooth motion until you hear a click. Do not continue to pull on the wrench once the click sounds.
A torque multiplier, when used with a torque wrench, generates a higher torque on the fastener while using a lower setting on the torque wrench. The actual torque multiplication or reduction factor normally is shown on the tool. In general, when using a torque multiplier with a torque wrench, the output is 3.3 times greater than the input.
Inside the tool, a set of planetary gears provides the torque multiplication. A full 360° clockwise or counter-clockwise rotation loosens or tightens fasteners. Input and output rotation directions are the same.
To tighten a fastener, attach the correct size socket to the wrench. Select the required torque value. Apply the needed torque clockwise for right-hand threads and counter-clockwise for left-hand threads. To loosen a fastener, follow the same procedure as outlined above, but replace the torque wrench with a work handle and apply the torque in the opposite direction.
What are some safety tips for using pipe wrenches?
What are some things I should avoid doing when using pipe wrenches?
What are some safety tips for using pipe cutters, reamers, and threaders?
What are some things I should avoid doing when using pipe tools?
A screwdriver is a hand tool with a blade, shank, ferrule, and handle. There are three main types of screwdrivers. The standard type has a flat blade and a slot-shaped tip. The Reed and Prince type has a pointed tip and a fluted blade. The flutes of the blade are set at 45-degree angles from the axis of the shank. The Phillips type has a blunt tip and beveled flutes on the blade that are set at 30-degree angles from the axis of the shank (see Figure 23).
Figure 23: Types of Screwdrivers
The screwdriver is one of the most basic and essential hand tools. It is also the most frequently misused and abused. Screwdrivers have one function and one function only, and that is to drive and remove screws. Screwdrivers are often misused as pry bars to pry nails and tacks from boards, remove lids from paint cans, chisel wood, etc. Using a screwdriver as a pry bar tends to round the corners off the tip, put nicks into the tip, and distort its shape so that it no longer fits well into a screw slot.
Screws come in a variety of shapes and sizes, each having a slot of specific width and depth. To work well, the tip of the screwdriver should fit the slot as closely as possible. Since the slots vary in size and shape, there must be different sizes and shapes of screwdrivers available for use.
An offset screwdriver is used where there is insufficient room to use a conventional screwdriver (see Figure 24). An offset screwdriver is simply a steel bar, either hexagonal or round, with the ends bent at right angles and ground to form a screwdriver tip. It is double-ended and can be used for cross-head or slotted-head screws. Combination cross-head and slotted-head screwdrivers are also available.
Figure 24: Offset Screwdriver
Before use, inspect the screwdriver tip to ensure that it is smooth and not chipped or otherwise damaged. Inspect the handle to ensure that it is securely fastened to the shank and that it is free of cracks and splinters.
The right size and shape of screwdriver must be chosen to fit snugly into the screw head. The tip should fit the width of the slot snugly and should be wide enough to fill the length of the slot. A screwdriver with the longest possible shank is always used. The arm and hand are aligned with the screwdriver to form a straight line from the elbow to the fastener. The free hand is used to hold the blade of the screwdriver in place on the screw or fastener. Downward pressure is applied as the handle is turned. The screw or fastener should not be over-tightened.
The tip of the screwdriver is dressed when necessary to restore the proper angle of the flutes or to repair damage.
There are numerous types of pliers in a variety of sizes. A brief description of each type, along with procedures for their use and care, is outlined in this section.
Before use, inspect the joint of the pliers to make sure that there is no looseness or play. Inspect the jaws to make sure that they are not bent and that the teeth or cutting edges are not damaged. Wipe pliers clean with a lightly oiled cloth after use to prevent corrosion.
Slip-joint pliers are a holding tool that consists of two handles with serrated jaws that are joined at a lap or box joint, which is held together by a pin, rivet, or screw. These pliers can be adjusted to two positions. Slip-joint pliers are used to grip work and apply a twisting force (see Figure 25).
Figure 25: Slip-Joint Pliers
Open the jaws and adjust the pliers to fit the work. The first hole in the lap joint is for small objects, and the second hole is for large objects. To prevent the work from slipping, grip the work so that the entire surface of the jaws touches it, if possible. Pliers are not to be used on energized electrical circuits or moving parts. Pliers are not to be used on delicate work or on bolt heads that can be damaged by the serrated jaws. Slip-joint pliers are not to be strained by use on objects that are too large to grip properly.
Locking pliers have a lever at the base of one handle and an adjusting screw at the base of the other handle. The jaws of the pliers are hinged so that they will lock onto the work when the handles are squeezed together. The lever releases the pliers from the work, and the adjusting screw is used to change the size of the jaw opening. This type of pliers does not have to be held in position on the work (see Figure 26).
Figure 26: Locking Jaw Pliers
Locking jaw pliers are used in situations that require a large amount of gripping pressure and also when the worker needs both hands free to complete other tasks. For example, locking pliers might be used to grip a corroded pipe while the worker uses his hands to hold a wrench and break the connector free.
Locking jaw pliers are not used unless the jaws will fit at least halfway around the object. Use the adjusting screw to open the jaws. Place the pliers on the work so that the jaws are parallel to one another, then squeeze the handle to lock the jaws. Support the pliers with one hand or another object to prevent them from slipping. Press the release lever to remove the pliers from the work.
Parallel jaw pliers have one handle with a series of grooves and another handle with a land that fits into the grooves. Parallel jaw pliers can grip a large size range of objects by placing the land in different grooves. They can have either serrated or non-serrated jaws. When open, the jaws are almost exactly parallel to one another (refer to Figure 27).
Figure 27: Parallel Jaw Pliers
Parallel jaw pliers grip objects that are either too large or too thin to be handled by regular slip-joint pliers. When using parallel jaw pliers, the land is set in the appropriate groove for the size of work that is being performed. Set the pliers on the work so that the jaws are parallel to one another. Pull on the handle connected to the lower jaw to complete the task.
Round nose pliers have small, narrow, tapered jaws with serrated teeth and blunt tips (see Figure 28). Round nose pliers are designed for working with medium- to heavy-weight wire and circuitry, such as that found on recording and control devices. They also are used to twist, bend, and grip pins and other objects in tight places.
Figure 28: Round Nose Pliers
Grip the work between the jaws and then twist or bend the pliers, depending on the application. Do not use round nose pliers on work that can be damaged by serrated jaws.
Needle nose pliers are small pliers with long, tapered jaws that have pointed tips. The jaws are covered with fine teeth or ridges (see Figure 29).
Figure 29: Needle Nose Pliers
Needle nose pliers are designed to twist or bend light-weight wire and for working with fine circuitry in tight places. Prior to use, the tips and teeth are inspected for wear and damage, and the joint is checked for looseness or play. Grip the work firmly between the jaws and then twist or bend, depending on the application.
Combination cutting pliers are slip-joint pliers that have a cutting notch at the back of each of their serrated jaws (see Figure 30).
Use combination cutting pliers to grip work and to cut small nails, cotter pins, and stiff wire. To use, open the jaws far enough for the cutting edges to line up. Insert the work through both cutting notches, then squeeze the handles together to cut the work. Sharpen the cutting edges with a file when necessary.
Lineman’s cutting pliers are cutting and gripping pliers that have serrated grippers at the tips of the jaws and knife-like cutting edges that extend from the rear of the grippers to the hinge on the pliers (Figure 31).
Figure 31: Lineman’s Cutting Pliers
To cut heavy wire and metal strips of medium thickness, set the work between the cutting edges, as far back in the jaws as possible, then squeeze the handles. The proper care of lineman’s cutting pliers is the same as for combination cutting pliers.
Diagonal cutting pliers are smaller than either combination or lineman’s cutting pliers. They have slightly curved jaws that allow the work to be cut at a variety of angles. Diagonal cutting pliers do not have any teeth or gripping surfaces. The jaws have cutting edges only. Refer to Figure 32.
Figure 32: Diagonal Cutting Pliers
Use diagonal cutting pliers to cut wire, cotter pins, small nails, and light-weight strips of metal. Place the work as far back in the jaws as possible and squeeze the handle to cut the work.
Wire strippers are cutting pliers that are slightly larger than diagonal cutting pliers. They have two sets of cutting notches in the cutting edges of their slightly curved jaws. Refer to Figure 33.
Figure 33: Wire Strippers
Select the stripping notch that is slightly larger than the diameter of the metal core of the wire. Center the wire in the notch and squeeze the handles of the pliers. Next, turn the wire in the notch to make a second cut. This ensures that the insulation is severed completely. Finally, push the wire strippers toward the end of the wire to strip the insulation off.
Snap-ring pliers have point-tipped jaws that fit into internal or external snap rings. Refer to Figure 34.
Figure 34: Snap-Ring Pliers
There are three types of snap-ring pliers:
Figure 35: Internal/External Snap Ring Pliers
Figure 36: Convertible Snap-Ring Pliers
Before using, inspect the tips for damage. Make sure that the joint does not have any looseness or play.
To remove and insert internal and external snap rings:
Files are hand tools that smooth metal and wood, remove burrs and irregularities, enlarge and finish holes and slots, and sharpen cutting tools (see Figure 37). Files are classified by their cut (how the teeth are arranged on the blade) and their degree of coarseness. Coarseness is determined by the number of teeth per inch and the amount of space between the rows of teeth.
Figure 37: Typical File
The inspection requirements for all files are generally the same. The point, blade, and edges of the file are inspected for damage. The teeth are inspected for cleanliness and for sharpness. The file tang must fit snugly into the handle. Cross-sections of several common types of files are shown in Figure 38.
Figure 38: Types of Common Files
Flat files normally are 4 to 18 inches long. They are used to file flat surfaces. A flat file tapers in both width and thickness toward the point. It is the most common file for all types of work, except inside curves. Single-cut and double-cut flat files are available.
Half-round files usually are 4 to 18 inches long. They are used for all-purpose filing. The half-round file is the most useful of all the files, combining the features of both round and flat files. One side is rounded, and the other is flat, so the tool can be used on flat, concave, and convex surfaces. Half-round files can be used on both wood and metal.
Hand files normally are 4 to 18 inches long. They are also general-purpose files. The hand file is slightly different from other files. It is flat in cross-section, but it has parallel sides right up to the tip, tapering only in thickness. Hand files have one safe edge. It is useful for stepped work and other general jobs where a safe edge is needed or where both sides of a corner must not be cut simultaneously.
A pillar file is 3 to 8 inches long and is used to file narrow openings. The pillar file is a slimmer version of the hand file, with one safe edge. It is mostly used for slots and key ways. Narrow pillar files, about half the width of standard pillar files, are used for very small orifices.
Square files are 4 to 20 inches long. They are used to file square holes or angles. Square files are used primarily on rectangular slots, keyways, and splines. Some models have three toothed sides and a fourth, safe side. In a confined space, the file can rest on its safe edge without damaging the work.
Round files are 4 to 20 inches long. They are used to file round holes or curved surfaces. A round file tapers toward the point and is used to enlarge or smooth round openings and to finish concave surfaces. Small versions of round files are called rat-tail files.
Triangular files are 2 to 18 inches long and are used to file angular stock. Triangular files have three flat, tapered sides. They are used to file acute internal angles, clean out and cut square corners, enlarge and clean up angular holes, and sharpen serrated jaws.
Swiss pattern files are small, delicate files used for fitting parts of delicate mechanisms, filing work on instruments, and tool and die work. They are designed in 12 different shapes and 7 cuts. They have knurled handles and usually come in sets of 8 or 12 assorted files.
Selecting the proper file for the job is very important. First, the type, size, and shape of file that is needed should be determined. Secondly, the cut and degree of coarseness needed to do the job are determined. Table 1 provides some guidelines for selecting appropriate types, sizes, and shapes of files for various types of work.
Table 1: Guidelines for Selecting Appropriate Types, Sizes, and Shapes of Files
Files are graded by their cut (the arrangement of their teeth) and the degree of coarseness (the depth and size of the teeth). Files may be single or double cut. Single-cut files have rows of teeth running parallel to one another along the faces of the file. Double-cut files have criss-crossed rows of teeth running along the faces of the file. The teeth are arranged in diagonal rows. The first set is called the over cut. The second set is called the up cut, and it is not as coarse or deep as the over cut. Single-cut files are used for sharpening or finishing work, and double-cut files are used to remove large amounts of metal and for work with rough surfaces.
Files come in six degrees of coarseness: rough, coarse, bastard, second cut, smooth, and dead smooth. Rough, coarse, and bastard files are used to remove metal and to file rough work. Second-cut, smooth, and dead-smooth files have smaller teeth and are used for finishing work. Refer to Figure 39.
Figure 39: File Cuts
Filing is harder than it looks and requires practice on scrap pieces before the skill is perfected. Always clamp the work in a vise, preferably at elbow level. To prevent vibration, the work is set low in the vise. Files cut on the forward stroke only; thus, you should apply even pressure as the file is pushed across the work. Even pressure is then applied on the return stroke to help keep the file cuts clean. Slow, steady, light filing strokes help to avoid rounding off the corners of the work.
Draw filing puts a smooth finish on the work, removing all cross-filing marks. For best results, grip the file with both hands close together to avoid bending or breaking the file. Smooth, even strokes are made along the length of the work. Draw filing must not be overdone or a hollowing of the work surface may result.
When lathe filing, place the work in the lathe and stroke the file along the length of the work as it rotates. Smooth, even, forward strokes provide the best results.
When filing round stock, the ability to rock the file is an advantage. The file must be constantly angled so all the teeth come into contact with the work surface. Table 2 provides some guidelines for selecting the appropriate cuts and degrees of coarseness.
Table 2: Guidelines for Selecting the Appropriate Cuts and Degrees of Coarseness
To remove a file handle, hold the file in one hand with the handle held in the other. Pull on the ends while striking the ferrule end of the handle against a work bench or table. The handle will loosen from the file. To install a file handle, insert the tang end of the file in the handle socket. The handle is then tapped on a work bench or table until the file is securely seated in the handle. Never use a file without a handle. New files are broken in by using them on brass, bronze, or smooth work with a relatively wide surface to avoid breaking the teeth. Chalk is rubbed between the teeth of new files before using them to avoid pinning (clogging of the teeth).
Files are cleaned with a file scorer, also called a file card, and a file cleaner brush when necessary. Holding the scorer blade parallel to the rows of teeth, use a pulling motion to score the file. The file is brushed with a pulling motion, and the brush is held parallel to the rows of teeth. Files are stored so that the blades do not touch one another, and they are wrapped in waterproof barrier wrapping paper. Rust retardant or lubricants are not to be used on files. Files are not to be used for any purpose other than filing.
A vise is a holding tool with a pair of jaws. One or both of the vise jaws may be adjustable, and the device usually is mounted on a work table or bench. Figure 40 shows the most common vise types. A detailed description of vises and the procedures for their use and care are described here.
Figure 40: Bench Vises
A mechanic’s bench vise has two serrated jaws, one of which is fixed to the base while the other is attached to a slide. The adjustable jaw is controlled by a screw that is turned with a sliding bar handle. The vise may have a swivel base bolted to a work bench or table, which allows the body of the vise to be rotated when a locking screw is loosened.
The mechanic’s bench vise is a general-purpose holding tool suitable for gripping a variety of work that will not be damaged by the serrated jaws. Prior to use, the vise jaws are inspected for damage. The locking device and adjusting screw are also inspected for damage.
The jaws of the vise are opened by turning the sliding bar and adjusting screw counter-clockwise. The work is positioned between the jaws, and the jaws are then tightened by turning the sliding bar clockwise. Soft jaws or blocks of wood are used to protect finished work from the serrated jaws. The vise jaws should not be overtightened. Ensure that the jaws come in contact with as much of the work surface as possible. Work that is too large to fit between the jaws is not to be put into the vise.
Clean any metal filings from the jaws and the base of the vise after each use. Wipe the vise clean with a lightly oiled cloth after each use. Vise parts are to be lubricated as necessary.
A machinist’s bench vise looks and works like the mechanic’s bench vise. However, a casing covers the screw and prevents filings and bits of metal from entering the area. In addition, part of the casing forms an anvil, which allows pounding with a hammer for shaping metal and setting rivets.
The uses and pre-use inspections for a machinist’s vise are the same as for a mechanic’s vise. The procedures for use and proper care of a machinist’s vise are also the same as for a mechanic’s vise.
The bench and pipe vise resembles the mechanic’s bench vise, except that it has a secondary set of jaws positioned below the main jaws. This vise can be used as a mechanic’s bench vise, but the secondary set of jaws is specifically designed to hold pipe or round stock. Follow the same inspection procedure for a bench and pipe vise as for a mechanic’s bench vise.
When using the principal set of jaws, the procedures for use for a bench and pipe vise are the same as for a mechanic’s bench vise. When using the secondary set of jaws to hold pipe or round stock, the pipe or round stock is positioned in the secondary jaws. Strips of copper, lead, or other soft material are placed between the jaws and the work to prevent damage to finished pipes or pipes made of a soft material. Finally, to tighten the secondary jaws, turn the slide handle clockwise.
The proper care of a bench and pipe vise is the same as for the mechanic’s bench vise.
A yoke pipe vise has an inverted U-shaped frame. One end of the frame is hinged to the base of the vise, which has a V-shaped seat. The other end of the frame has a locking device to secure the yoke to the base after the work is inserted. A screw device is located at the top of the yoke to hold the work in place. A yoke pipe vise is designed specifically to hold pipes (see Figure 41).
Figure 41: Yoke Pipe Vise
Before use, inspect the yoke to ensure that it is not bent or otherwise damaged. Check the threads on the screw device, yoke hinge, and locking device for damage. The vise seat's serrated edges should not have any wear or damage; otherwise, the grip on the pipe will not be secure.
To use, unlatch the locking device on the yoke. Back out the screw at the top of the yoke. Then, insert the work into the V-seat. Swing the yoke back into position and lock it to the frame. Tighten the screw device to hold the work firmly in place. Follow the same procedure for care of the yoke pipe vise as for a mechanic’s bench vise.
An adjustable drill-press vise is a type of bench vise that is mounted on a drill-press table with bolts that run along T-slots on the surface of the table. It can be positioned anywhere along the surface of the table by loosening the nuts on these bolts and moving it to the desired position. This vise also has a swivel base and curved tracks along its sides that allow it to be positioned at various angles (see Figure 42).
Figure 42: Adjustable Drill-Press Vise
Designed mainly for use with a drill press, the adjustable drill-press vise shown holds the work firmly on the drill-press table and prevents it from moving during drilling.
Before using, inspect the jaws of the vise for wear or damage. The ability to move the vise along the tracks in the table and also to make angular adjustments is checked by loosening the bolts and moving the vise through its full distance of travel.
Position the vise on the drill-press table by loosening the bolts and moving the vise. Then, re-tighten the bolts on the drill press table. Open the jaws on the vise by turning the adjusting handle counter-clockwise.
Next, position the work in the jaws and secure it in the vise by turning the adjusting handle clockwise. The vise is adjusted for the proper drilling angle by loosening the bolts on the side of the vise and tilting the vise to the desired position. Then, re-tighten the bolts on the side of the vise. Proper care of the adjustable drill-press vise is the same as for the mechanic’s bench vise.
The chain pipe vise has no jaws. It consists of a base with a V-shaped seat and a chain. The chain’s links are held together by rivets that extend beyond the end of each link. One end of the chain is attached to the body of the vise with an adjusting bolt. The body of the vise has a notch or lip, which is designed to secure the free end of the chain after the work is positioned in the vise. Refer to Figure 43. The chain pipe vise holds pipes and round stock. The chain enables the vise to hold round stock and pipes securely and allows pressure to be applied evenly, which helps to prevent damage to pipes.
Figure 43: Chain Pipe Vise
Before using, check the condition of the chain to make sure that the links are not damaged and that the rivets are not bent or broken. Inspect the adjusting bolt for wear or damage.
Place the work in the V-shaped seat of the vise. Wrap the chain around the work. Secure the rivet at the free end of the chain in the notch or lip at the base of the vise. Turn the handle at the base of the vise to tighten the adjusting bolt and secure the work in the vise. The adjusting bolt should never be over-tightened.
Clean the vise after each use. Wipe the chain clean with a lightly oiled cloth to prevent corrosion.
Clamps are portable holding devices that are screw- or spring-operated. The most common types of clamps are the C-clamp, the welding table clamp, and the spring clamp.
A C-clamp is a clamp with a C-shaped frame, which is attached to a screw device that is operated by turning a handle at the end of the frame (see Figure 44). The other end of the frame has a small, flat anvil. C-clamps are used to secure work to benches or tables. Work is held between the anvil and a swivel disk at the end of the screw device.
Figure 44: C-Clamp
Before using, inspect the C-clamp frame and anvil to ensure that they are not bent or otherwise damaged. Inspect the threads on the screw device for wear or damage. The swivel disk must be firmly attached to the end of the screw device.
Open the clamp by turning the screw device counter-clockwise. Set the surface of the work flat against the anvil of the C-clamp. Finished work or soft materials are protected by inserting wood, copper, lead, or other soft materials between the work and the clamp’s anvil and disk. Turn the screw device clockwise until the work and table are pressed securely between the anvil and disk. C-clamps should not be over-tightened, nor should they be strained by trying to grip objects that are too large for the clamp. To remove the C-clamp, turn the screw device counter-clockwise.
After use, wipe the clamp clean with a lightly oiled cloth to prevent corrosion. Repair the threads on the screw device as necessary.
A welding table clamp has a T-handled screw device at one end of its frame and a square head bolt and nut at the other. Refer to Figure 45.
Figure 45: Welding Table Clamp
The welding table clamp works with the welding table to hold work when welding.
To install, first turn the bolt head so that it will not catch on the corners of the hole. The work is inserted between the swivel disk at the end of the screw device and the surface. Next, insert the square head of the bolt at the base of the clamp’s frame into one of the holes in the welding table.
Before use, inspect the threads on the bolt and screw device for any damage. The frame should be straight and have no visible damage.
The screw device is then tightened until the work is held securely to the table. The nut at the end of the bolt is tightened to compress the table surface between the bolt head and the base of the clamp.
The proper care of welding table clamps is the same as for C-clamps.
A spring clamp is a spring-loaded holding device with a pair of handles attached to a pair of metal jaws held together by rivets or pins (Figure 46).
Figure 46: Spring Clamp
Spring clamps are used for light-duty holding tasks, such as holding gasket material to a table.
Before using, inspect the jaws of the spring clamp for wear or damage. Also, inspect the spring for wear or damage.
Squeeze the handles to open the jaws. Secure the work between the jaws of the clamp. Release the handles to fasten the clamp to the work.
After use, wipe the spring clamps with a lightly oiled cloth to prevent corrosion. Store spring clamps on wall hooks or laid flat in a tool box. Keep spring clamps dry during storage or rust will form in the hinge pin, hampering movement.
Punches are relatively small cylindrical pieces of round stock that vary in size and shape according to their use or purpose. They are made to be struck by ball peen hammers to exert a force on a relatively small surface area.
Prick punches are long, tapered punches with beveled edges that come to a point (Figure 47).
Figure 47: Prick Punch
Prick punches, used for light to medium striking tasks, are most often used to make witness marks on metal surfaces. When using a prick punch, always wear safety goggles and a face shield. Mark the work at the point where a witness mark is needed. Set the point of the prick punch on the mark. Then, strike the end of the prick punch with a ball peen hammer.
Before use, inspect the tip for sharpness. If not sharp, an improperly located mark may result. Check the opposite, blunt end for mushroomed edges. Then, look at the shank. It should be straight and have no visible damage. If damage is apparent, dress the tip of the punch on a grinding wheel or emery wheel to restore the original shape and sharpness when necessary.
Center punches are very similar to prick punches. They are made of heavier metal stock and are slightly larger in size (see Figure 48). Center punches are used to make indentations in metal to give drill bits a true start.
Figure 48: Center Punch
Before use, make sure that the tip is sharp. Check the opposite, blunt end for mushroomed edges. These can fly off, causing eye injury.
When using a center punch, safety goggles or a face shield are always worn. To use, first mark the exact spot where the hole is to be drilled. Place the point of the punch on that spot. Then, precisely strike the end of the punch with a medium to heavy ball peen hammer. Strike the punch with enough force to make the indentation on the first strike, as this will prevent distortion of the indentation. The tip of the punch can be dressed on a grinding wheel or an emery wheel to restore the original shape and sharpness.
A drift punch has a blunt end and a thick, heavy body that tapers to a narrow shank with a flat end (Figure 49).
Figure 49: Drift Punch
Before using a drift punch, check it for mushroomed edges and a bent or otherwise damaged shank. If damaged, the tip of the punch can be dressed on a grinding wheel or emery wheel to restore its original shape.
Drift punches are used to break alignment pins free in machinery. Select a drift punch that has a tip slightly smaller in diameter than the pin to be driven out. Hold the blunt end of the punch against the pin. If the pin is tapered, hold the punch against the narrower end of the pin to avoid jamming. Then, strike the end of the punch with a medium to heavy ball peen hammer.
A pin punch has a uniformly narrow body and a blunt end (see Figure 50). Pin punches are used to drive pins out of their seats after a drift punch has been used to break them free. A pin punch is selected that is slightly smaller in diameter than the pin that will be worked on. The blunt end of the punch is placed against the pin. The opposite end of the punch is struck with a light to medium ball peen hammer.
Figure 50: Pin Punch
Before use, check the ends of the punch for mushroomed edges and a bent or otherwise damaged shank. If damaged, the tip of the punch can be dressed on a grinding wheel or emery wheel to restore its original shape.
An alignment punch is a long, gradually tapered punch with a blunt end (Figure 51). Alignment punches have two uses: to install alignment pins in equipment and to line up holes in components.
Figure 51: Alignment Punch
Before use, inspect the ends of the punch for mushroomed edges and a bent or otherwise damaged shank. Insert the alignment punch through the hole as far as it will go. Then, lightly tap the alignment punch with a hammer. Place the alignment pin against the tip of the punch. As the alignment punch is pulled out of the hole, the alignment pin is pushed in. Lightly tap the alignment pin with a ball peen hammer to seat it, if necessary. The tip of the punch can be dressed with a grinding wheel or emery wheel to restore the original shape of the punch end.
A hole, or gasket, punch is a punch with a sharp-edged, hollow, circular end (Figure 52). Hole, or gasket, punches are used to cut holes in gasket material, plastics, rubber, and soft metals.
Figure 52: Hole, or Gasket, Punch
Before use, make sure the punch cutting edges are sharp; otherwise, an inaccurate or ragged hole may result.
The holes to be cut are outlined on the material with a pencil or chalk. Place a block of wood under the material to cushion the impact on the punch and to protect the work surface. Select the proper sized hole punch and place the circular end of the punch against the hole markings. Then, with a ball peen hammer, strike the end of the punch to make the hole.
The circular end of the punch may need cleaning out after use. After extended use, it may become necessary to sharpen the circular edges of the punch with a file. For protection against rust, coat the edges of the punch with a light film of oil after filing. Store the punches so that they do not bang against other metal objects to avoid damaging the edges.
A chisel is a cylindrical piece of heavy metal with one broad, flat end and a shank that tapers to a sharp cutting edge. Chisels are used for chipping and cutting. Chisels are classified according to the shape of their points. The width of their cutting edge denotes their size. Figure 53 shows five common types of chisels.
Figure 53: Types of Chisels
Before use, inspect the cutting edge of a chisel for sharpness. Inspect the shank to ensure that it is not bent or otherwise damaged. Chisels are cleaned with a lightly oiled cloth to prevent corrosion. The cutting edges can be dressed on a grinding wheel or an emery wheel to restore the original shape and sharpness when necessary. Table 3 provides a description of each type of chisel.
Table 3: Description of Various Chisel Types
The procedure for using a chisel is described in the following steps:
Drills are end-cutting tools made from either high-speed steel or special alloys. The most common type of drill is the twist drill. Twist drills have a straight shank, or shaft, with two helical flutes and two cutting edges on the body. The drill point is set at a 59° angle to the axis of the drill.
Tapered shank drills are widely used in many plants. They are not subject to slippage like straight shank drills. They normally are used with auxiliary tapers that make them fit snugly into the drill press. Tapered shank drills are used for larger holes of 3 to 5 inches.
Drills are used to cut round holes in metal, wood, or other materials. They may be driven electrically with a drill press or power hand drill, or manually with a hand-operated breast drill. Before attempting to drill, the drill bit should be clean and sharp. Check for the proper drill point angle of 59° and an 8° to 12° lip clearance (see Figure 54).
Figure 54: Measuring Drill Point Angle and Lip Clearance
Should it become necessary to sharpen a drill bit, start by checking the point angle, lip clearance, and chisel edge with a drill point gauge. Place the cutting edge surface on the grinder abrasive wheel at a 59° angle while the wheel is turning. The drill is rotated clockwise while lowering the shank so that the curved edge contacts the grinding wheel at a 59° angle. Both edges are ground and then checked with a drill gauge to ensure that the point angle is correct. Also, measure that the drill lips are equal and that the point is at dead center.
Reamers are cylindrical pieces of stock, similar to drills, that have spiraled or straight fluted cutting edges along their bodies. Reamers finish drilled holes to precise diameters, usually within .0001 inch. Reamers, like drills, are used with power hand drills, drill presses, or held in a tap wrench and turned by hand. The type used determines how it is driven.
Before using, inspect the reamer for cleanliness and ensure that the cutting edges are sharp and undamaged. Reamers are cleaned and well-oiled after each use. To keep the cutting edges sharp, store reamers away from other tools in padded or wooden boxes.
Taps look like screws that have channels or flutes cut straight up along their sides. The surfaces in between these flutes are threaded and, depending on the type of tap, the thread, or chamfer, length varies. The flutes permit chips of metal to escape and lubricant to reach the cutting edges and threads when the tap is being used.
Taps differ in a number of ways. Taps differ in the size of their bodies, or the threaded portion of the tap. They differ in their chamfer length, or the length of the threaded section at the front of the tap, which does not cut. They differ in their cutting faces, or the leading edge of the threaded portion of the tap, or the land, and they differ in their back taper the difference in the height of the leading edge and the trailing edge of the threaded portion of the tap.
Taps cut internal threads into metal, plastic, or hard rubber. Three types of taps are used in normal tapping operation: taper hand taps, plug hand taps, and bottoming hand taps.
Pipe taps are used to make internal threads on pipe fittings or in other places where an extremely tight fit is important. The diameter of the threaded section of the pipe tap is tapered to the end. The outside diameter of the pipe tap remains the same, but the root diameter tapers toward the body of the tap. All of the threads on a pipe tap cut threads.
Before using a tap, inspect the condition of the threads to ensure that they are clean and not broken or damaged.
The procedure for the use of taps is outlined in the following steps:
Remove all chips from the threads and flutes and apply a light film of oil with a clean rag before storing. Since taps are cutting tools, protect them from possible damage from other tools when they are stored. Taps should be kept in their original individual packaging or in the tap set box.
Dies resemble solid hex nuts in which flutes have been machined with threads and hardened to make cutting edges. Dies vary in size and shape according to the function for which they are being used. The most common types of dies are square pipe dies, die nuts, and round-split adjustable dies (see Figure 55).
Figure 55: Thread Dies
Dies have fewer threads and larger flutes than taps. The larger flutes help the metal chips escape from the cutting area.
Dies have either a short or a long chamfer. Dies with a short chamfer are designed to thread close to a shoulder, and dies with a long chamfer are used on jobs where 2-3 incomplete threads can be tolerated. The chamfer on the die may be equal on both sides, in which case it provides balanced cutting. The standard chamfer on the front face of a straight thread die is 2-3 threads, with 1 or 1-1/2 threads on the rear face. Standard taper thread dies have a front chamfer of 2-3 threads but have no threads on the rear face.
Dies are used with die stocks, which are specially designed handles used to turn dies during the threading operation. A re-threading die or die nut, however, can be used with a wrench because of its hexagonal shape.
Before using, inspect the die to ensure that it is clean and free of foreign materials. Inspect the cutting edges of the die to ensure that they are sharp and free of nicks or chips. The work must be clean and free of burrs.
The procedures for the use of a die to cut threads on round stock are outlined in the following steps:
The procedures for the use of a die to cut threads on pipe are outlined below.
Keep dies clean and well-oiled. Store them so they are away from other tools. Place them in padded or wooden storage boxes when not in use.
A portable hand drill is a hand power tool that comes in sizes that can accommodate drill bits from 1/4 inch to 1 inch in diameter. The most common size is the 1/2 inch portable hand drill (see Figure 56).
Figure 56: Portable Hand Drill
A portable hand drill holds and turns a drill bit to produce holes in various materials. Before using, inspect the condition of the drill chuck and drill body for damage. Also, inspect the condition of the drill cord to ensure that the wire casing and plug are not damaged. The drill must be properly grounded.
To use a portable hand drill, perform the following steps:
Clean drill after each use and remove the drill bit from the drill before it is stored. Store drill in a dry place with the cord wrapped around itself.
A drill press is a stationary drilling tool that has an electric motor mounted in a metal housing. A drill chuck is geared to the end of the motor shaft to hold drill bits. The drill press, like the portable hand drill, is used to turn drill bits to produce holes in various materials. Before using, inspect the drill chuck for damage. Clean off the worktable and mount a drill press vise or other suitable work-holding device. When finished, remove the drill bit or reamer from the chuck and store both properly. Clean the drill press table after each use.
The procedure for using a drill press is outlined below.
A reciprocating saw is a power tool with a blade attached to a housing, similar to that of a portable hand drill (see Figure 57). The blade moves back and forth to cut material when the saw is operating. The reciprocating saw accepts a variety of blades to cut different materials. Reciprocating saws cut metal, wood, and other materials.
Figure 57: Reciprocating Saw
Before using, inspect the blade for any missing, broken, or bent teeth. Check the cord and plug for damage. Wipe the blade clean after each use with a lightly oiled cloth to prevent corrosion. Remove the blade from the saw before storing.
The procedure for using a reciprocating saw is outlined below.
A circular saw is a power tool with a high-speed motor encased in a housing (Figure 58). A circular blade is attached to the motor. Circular saws can be fitted with a variety of blades for cutting different types of material. Circular saws are used to cut wood, plastics, and materials other than metal.
Figure 58: Circular Saw
Before using, check the condition of the saw blade to ensure that it is not bent and that it does not have any broken or damaged teeth. Also, check the blade guard for freedom of movement. Inspect the cord and plug for damage. Wipe the blade clean with a lightly oiled cloth after each use to prevent corrosion.
The procedure for the use of a circular saw is outlined below.
A wood saw consists of a handle and a blade that has teeth along the cutting edge (see Figure 59). The teeth of a saw can vary in pitch, or the number of teeth per inch. The most common pitch is 18 teeth per inch. Rip-cut saws have coarse teeth and are used for cutting lengths of wood that do not require a fine finish. Cross-cut saws have fine teeth and are used for finishing work.
Figure 59: Wood Saw
Before using, inspect the teeth to ensure that they are not bent or broken. Check the blade and handle to ensure a snug fit. Clean any foreign matter from the teeth after each use. Wipe the saw blade with a lightly oiled cloth to prevent corrosion.
Wood saws are used to cut wood and materials other than metal. The proper pitch saw is selected for the job. A saw with a greater number of teeth per inch is used for light jobs, and a saw with fewer number of teeth per inch is used for heavy work. The work is secured in a vise or on a work bench or table. The spot is marked where the object is to be cut. The saw is set on the work and moved back and forth with smooth, even strokes.
A hacksaw has a metal frame with a pistol grip handle. The frame adjusts to fit various-sized blades. The pitch of hacksaw blades ranges from 14 to 32 teeth per inch. The most commonly used is the 18-pitch blade (see Figure 60).
Figure 60: Hack Saws
Hack saws generally are used to cut metal. Prior to use, the blade is inspected to make sure that it is not bent or damaged. The teeth are inspected to make sure they are not bent or broken. The blade must be securely attached to the handle. Foreign material is cleaned from the blade and frame after each use. The saw blade is wiped with a lightly oiled cloth to prevent corrosion.
The work is secured in a vise or on a work bench. Safety goggles or a face shield are always worn when using a hack saw. The work is marked where the cut is to be made. The cut is started with a light forward stroke. The blade is drawn back without applying any pressure. This action is continued, applying pressure only on the forward strokes. Long strokes are made so that the entire surface of the blade is used. This, in turn, prevents uneven wear of the blade.
There are two basic types of hand pipe cutters: the wheel-and-roller cutter and the two-wheel cutter. They are similar in construction. Both have a C-shaped frame attached to a shank. The shank has a T-shaped handle at one end and threads on the other end that fit into the bottom of the frame. Turning the handle allows the adjustment of the opening in the frame to hold pipes of various sizes snugly. One end of the frame is stationary, and the other end moves when the handle is turned. The cutter is positioned in the stationary end of the frame, and the rollers are in the movable end of the frame. The rollers hold the pipe securely when the pipe cutter is rotated. Refer to Figure 61.
Figure 61: Pipe Cutter
Hand pipe cutters are used to cut steel, wrought iron, iron, brass, copper, or lead pipes that are less than three inches thick.
Before using, check the condition of the cutter and the rollers. They should spin freely. Also, check the condition of the threads on the shank. The movable portion of the frame must move smoothly. Look the frame and shank over to ensure that they are not bent or damaged.
When using a one-wheel pipe cutter, cutting oil is applied to the pipe. The point is marked where the pipe is to be cut. The pipe is then secured in a pipe vise. The cutter is placed on the mark. The cutter is then turned around the pipe one full circle as the T-handle is tightened. Continue to rotate the cutter on the pipe and tighten the handle until the pipe is cut through.
When using a three-wheel pipe cutter, follow the same procedures as when using a one wheel pipe cutter, except make half turns with the cutter instead of full rotations as you tighten the T-handle. After use, clean out any chips and wipe the pipe cutter with a lightly oiled cloth to prevent corrosion. The pipe cutter should be stored on wall racks. The rollers and cutter may need to be replaced when they show signs of wear.
Select a heavy-duty tubing cutter for making clean right-angle cuts on large tubing when space permits. The rollers make turning easy, and the tool is long enough to provide adequate leverage for cutting large tubing. The junior cutter is useful in limited spaces and cuts tubing without causing the tubing to flatten.
When tubing is cut off, the pressure of the cutting wheel often causes a slight reduction of the inside diameter of the tubing. It may then be necessary to remove the indented or burred edge. Use the reamer and file on the heavy-duty cutter or a separate deburring tool designed for this purpose.
All tubing bending should be done with special tools to form a uniform bend that is not kinked. If tubing becomes kinked during bending, the inside diameter is reduced considerably and the tubing may become useless. The smaller tube sizes can be bent with spring benders. If more accurate bends are desired, the small-diameter tube bender should be used. It can form bends without the danger of collapsing or denting the tubing. If stiff tubing must be bent or appearance is important, select the lever-operated tube bender. The lever-operated benders are also available in metric sizes.
To make connections on soft copper and aluminum tubing without fittings, use a swaging tool to enlarge one tubing end.
Select tubing wrenches for loosening all tubing fittings. These fittings may collapse or be deformed if the extra-strong tubing wrenches are not used.
A pipe threading set (Figure 62) contains an assortment of cutting dies (1), a handle or wrench (2), a collar (3), and locking screws (4). The cutting dies may range from 1/8 inch to 2 inches in diameter. The threading set is used to cut American Standard Pipe threads on steel, brass, copper, wrought iron, and lead pipe.
Figure 62: Pipe Threading Set
NOTE: If metal shavings become clogged in the die, remove the die and clean it with a piece of cloth.
Tube cutters (Figure 63) have a cutting blade (1), guide rollers (2), and an adjusting screw (3). Some cutters have a reaming blade attached to the frame of the cutter. Tube cutters can cut sizes from 1/8 inch through 2-5/8 inches tubing. They can cut copper, aluminum, or brass tubing.
Figure 63: Tube Cutters
Flaring tools (Figure 64) come in two basic types: single and double. They are used to put flares in soft tubing. The single flaring tool consists of a split die block, a locking clamp with a compressor screw, and a cone that forms a 45° flare on the end of the tube. The screw has a T-handle. The die block is constructed to be used on tubing with the following outside diameters: 1/8, 3/16, 1/4, 5/16, 3/8, 7/16, 1/2, 5/8, and 3/4 inch. The double flaring tool consists of a split die block, a locking clamp with a compressor screw, adapters for turning the tube edge, and a cone that forms a 45° flare on the end of the tube. The screw has a T-handle.
Figure 64: Flaring Tool
Tubing that becomes defective from use must be replaced, and the replacement often needs to be flared. For example, hydraulic brake line replacements are made in standard lengths, such as 3 or 4 feet, and may need to be cut to length and then flared. Since pressures may reach over 1,000 psi, only steel tubing (usually double walled) can be used for hydraulic brake or power-steering metallic lines. At these pressures, copper tubing would either stretch or rupture.
Flaring tools are manufactured from high-quality tool steel. Popular models can flare tubing with an OD (outside diameter) of 3/16, 1/4, 5/16, 3/8, 7/16, 1/2, and 5/8 inch.
Two methods are used for clamping the tubing in the tool. The model shown in Figure 65 pivots at one end to open up. This provides easy access for placing the tubing between the die bars. The die bars can then be tightened together by wing nuts.
Figure 65: Single-Lap Flaring Tool Having Two Die Bars
The model shown in Figure 66 has sliding die blocks instead of die bars. Each die block forms one half the gripping surface for each tubing size. By tightening the end clamping lever, the die blocks are pushed together to hold the tubing.
Figure 66: Single-Lap Flaring Tool Having Sliding Die Blocks
Both types of flaring tools make use of either fine circular threads or chevrons to grip the tubing so that it is not forced down through the tool during the flaring operation (Figure 67).
Figure 67: Two Means of Gripping Tubing in the Tubing Openings of a Flaring Tool
The yoke, which contains the tapered flaring cone, slides over the die bars or blocks. Most yokes feature a sliding T-handle or a large wing nut to produce the required leverage for making the flare.
A flaring tool used on soft tubing may rely on a smooth, chrome-plated cone to shape the flare above the sliding blocks (Figure 68). The sliding die blocks on this tool do not have a chamfer to form the flare. Special flaring tools are made for use on certain nylon or plastic tubing. Metric flaring tools are available for tubing sizes of 4, 6, 8, 10, 12, 14, and 16 millimeters.
Figure 68: Flare Being Shaped by Forming Cone of a Single-Lap Flaring Tool Used on Soft Tubing
Notice that in figure 68 there is no chamfer on the sliding die block.
Most flaring tools are used on tubing made from soft steel, as well as copper, brass, and aluminum. Use a single-lap flaring tool for making flares on tubing used under light-duty conditions. For double-lap flaring, a set having special adapters for each tubing size is required (see Figure 69).
Figure 69: Double-Lap Flaring Adapter and Tool Set
NOTE: Do not overtighten the cutter, as tubing may kink and flatten.
Keep the cutting wheel clean and lightly oiled. If a reaming device is mounted on the body of the cutter, keep it retracted when not in use. Store tube cutters on a rack or in a box.
Keep surfaces clean and lightly oiled. Close single flaring tools and tighten the cone into the block for storing. Keep double flaring tools in the case when not in use.
This section describes two types of tube benders: spring tube benders and hand tube benders.
The spring tube bender (Figure 70) is available for tubing sizes having a 1/4 to 5/8 inch OD. It consists of a special steel spring rolled to a size that slips over the tubing. One end is "belled" to allow the tubing to be easily inserted and removed.
Figure 70: Spring Tube Bender
The small-diameter tube bender in Figure 71 relies on forming dies to make accurate bends in tubing having outside diameters from 3/16 to 3/8 inch. This tool is capable of making bends of up to 180° with a 1 3/16 inch radius. The nylon half-moon forming pad can be flipped over to bend additional tubing. The pressure screw is turned with a wrench or sliding T-bar.
Figure 71: Small-Diameter Tube Bender
The lever-operated tube bender (Figure 72) bends only one tubing size; therefore, several tools may be required. This tool can make bends of up to 180° and has a dial to indicate the angle of the bend in degrees. Lever-operated benders are available for tubing up to 1 inch in OD.
Figure 72: Lever-Operated Tube Bender
Swaging tools enlarge the tubing end so that other tubing can be slipped inside to form a connection. Both of the swaging tools shown in Figure 73 need a flaring die bar to hold the tubing during the swaging operation. Various tool sizes can swage tubing of up to 7/8 inch OD.
Figure 73: Two Types of Swaging Tools
Tubing wrenches are shown in Figure 74. They are available in sets with size openings from 1/4 to 3/4 inch or more.
Figure 74: Tubing Wrenches
The hand tube bender (Figure 75) consists of the following components: a handle, a radius block (mandrel), a vise clamp block, and a roll support. The bender die is graduated from 0 to 180°, and the bender die has a scribe mark that indicates the degree of the bend. These benders are available in 3/16, 1/4, 5/16, 3/8, and 1/2-inch sizes. The hand tube bender is used to bend copper, brass, or aluminum tubing to specific angles.
Figure 75: Hand Tube Cutter
Figure 76: Using a Hand Tube Bender
A bench grinder consists of a housing that has an abrasive wheel mounted on the end of a motor driven shaft (Figure 77). The front of the housing has a tool rest and a transparent protective eye shield. Bench grinders are used to sharpen or to shape steel and iron objects.
Figure 77: Bench Grinder
Before use, inspect the condition of the housing for any damage. The abrasive wheel should have no cracks or other visible damage. Check the directional mounting of the abrasive wheel so that it will rotate in the proper direction. Also, inspect the cord and plug for damage.
The procedure for the use of a bench grinder is outlined below.
A portable grinder has a housing similar to that of a portable hand drill. It has a spindle mounted at 90 degrees on the front end that holds the abrasive wheel (Figure 78). Some portable grinders have a threaded hole at the front for a second handle to permit added control of the tool.
Figure 78: Portable Grinder
Portable grinders are used to shape or sharpen metal or iron and for sanding. Before use, check the housing, cord, and plug for any damage. Inspect the abrasive wheel being used for cracks and nicks. Also, inspect the spindle to ensure that it is not bent or damaged. Firmly secure the wheel guard on the front of the grinder. Clean portable grinders after each use. Store grinders in a dry place away from other tools.
The procedure for the use of a portable grinder is outlined below.