ASVAB: Shop Information Review

Measuring Tools

Rulers & Tape Measures
A ruler is a device with a straight edge used to measure length, generally in both centimeters (cm) and inches (in); these are generally subdivided into millimeters and sixteenths, respectively. Standard lengths for rulers are 12 inches (30 cm).
A tape measure is a flexible, often retractable, ruler used to measure length. Standard tape measures are measured in centimeters (with millimeter increments) on one edge of the tape and inches (with quarter-, eighth-, and sixteenth-inch increments) on the other. Some tape measures may include thirty-seconds or even smaller increments, which are required for more detailed projects.

Calipers
Calipers are precise measuring devices with sliding jaws used to measure two-dimensional inside measurements (an empty distance between two points) and outside measurements (the width or thickness of an object). Calipers can be digital or analog; analog calipers measure relatively precisely using a vernier (a graduated, sliding measuring device) or a dial (using a rack and pinion). Both calipers pictured have jaws for inside and outside measurements.
Calipers are used widely in mechanical engineering, woodworking, machining, and metalworking.



Vernier caliper


Dial

Micrometers
A type of caliper, micrometers are jawed devices used to measure the distance between two points. However, micrometers are much more precise, specialized, and difficult to use; they are most commonly used in machining applications and mechanical engineering.
Micrometers can measure to 1/20,000 of an inch, which makes them sensitive to even temperature, and they must be handled with skill and caution. Like calipers, they can measure inside and outside measurements, but with their specialized jaws, they can be used for other, more difficult, measurements, as well. Ball micrometers measure the thickness of curved parts, and offset centerline micrometers accurately measure the distance between the center of two holes.


Simple outside micrometer

Levels
Levels are used to determine if an object's surface is horizontal (level; 0°) or vertical (plumb; 90°) relative to the earth's surface, though this does not necessarily mean relative to the ground in the immediate area.  There are several different types of levels:
Spirit or bubble level: a tool containing or consisting of a small, clear tube filled with alcohol or another liquid and a small air bubble.
The tube is very slightly bowed so that when the level is perfectly horizontal, the bubble will be in the middle; the less bow the tube has, the more accurate the level will be.
Laser level: a tool utilizing a laser or series of lasers to establish a horizontal plane on the desired surface.
Optical level: a tool used by builders to establish grade (a level base or specific slope) across a large area, such as for foundations of buildings.
Water level: clear, flexible tubing filled with water used to create a horizontal line between distant objects (such as fence posts) or a large surface (such as a deck). When both ends are held steady and upright, the water lines in each tube will be in line with one another horizontally.


Diagram of water level

Plumb Bob
A plumb bob is a tool used to establish a vertical (plumb; 90°) reference line relative to the earth's surface, though this does not necessarily mean the ground in the immediate area. Laser plumb bobs work much like laser levels, but the simpler plumb bob, a weight with a point on the bottom hung from a string, can also be used to find the plumb-line or vertical reference line. To use the plumb bob, attach the end of the string to the upper point being measured. For example, tie the end of the string to a long nail at the top of a fence post. To be sure the fence post is upright, let the plumb bob swing unhindered until still. The bottom tip of the bob will hang perfectly vertically below the knot in the string above, and the line will be parallel to the fence post if it is plumb.

Squares
Squares consist of two straight edges set at 90° to each other and are used by carpenters, builders, and machinists, among others, to check for exact right (90°) angles. Perfect right angles are essential to proper function of doors and windows and the soundness of buildings and other structures, among other things. There are several different types of squares, depending on the project at hand. For

Speed square: a small, right triangle-shaped tool commonly used for guiding saw cuts, marking angles, and squaring lines. It can also be used as a substitute level and to assist with ripping wood (cutting wood parallel to the grain).
Framing or steel square: an L-shaped square with graduated edges used for cutting stair stringers and laying out rafters.
Combination square: a tool consisting of a ruler and interchangeable, sliding heads used most commonly in woodworking, stonemasonry, and metalworking. The square or standard head is the most common and is used to check 90° and 45° angles.
Drywall square: used for marking and cutting drywall for hanging, this T-shaped tool has graduated edges, the longest of which is 48 inches in order to accommodate squaring a standard sheet of drywall.

Striking Tools

Hammers
Hammers are tools with a weighted head on a handle used to strike with concentrated force on a small surface area, such as a nail head when driving it into wood. There are many different types of hammers, but some of the most common are:

Claw hammer: highly versatile, this hammer has a curved claw on the back side of the weighted head used for prying. Several other hammer variations include the claw, as well.
Rubber mallet: used in commonly woodworking and upholstery, the rubber head delivers more insulated force so as not to damage the work surface.
Sledge hammer: With a long handle and a heavy head, the sledge hammer is designed for driving stakes, breaking up masonry, and other jobs requiring maximum force and heavy blows.
Nail gun: Drives nails, powered most commonly by electricity or an air compressor.

Chisels
A chisel is a hand tool commonly used in woodworking with a long blade used to cut or shape wood, as well as stone, metal, or other hard materials. To use a chisel, be sure to have a firm, 2-handed grip: one hand guides while the other drives the chisel.
If more force is needed, a rubber mallet can be used to deliver the force to the end of the handle, but chiseling should always occur with the grain of the wood. Different types of chisels include:

Beveled edge chisels: The most basic of chisels, beveled edge chisels have a relatively thin blade with a flat back. Its square blade end has
3 acute beveled edges on the front side.

Mortise chisels: Sturdier than beveled edge chisels, mortise chisels have a thicker blade with a flat back. Its square end has just 1 beveled edge on the front side, which is less acute than that of a beveled edge chisel.



Beveled edge chisel



Mortise chisel

Punches
Used in conjunction with a hammer and sometimes a chisel, a punch tool or punch is a hard metal hand tool with a blunted end and a specialized pointed end used to mark the center for drawing circles, punch precise holes in hard material such as sheet metal or leather, start holes for drilling, and more. Hollow punches have a hollow interior and are used to create holes in the workpiece, and solid punches have a solid interior and are used for marking, to remove material from an area, or to drive small components such as pins precisely into place.

Turning Tools

Screwdrivers
Screwdrivers are hand tools used to apply torque (a twisting force used to cause rotation); most commonly, they are used to turn screws using the groove patterns on the screw head with the corresponding shape at the end of the screwdriver:




Common screwdriver types
On the left, the Phillips-head screwdriver forms a cross at the end of the screwdriver. The flat head screwdriver is a simple wedge shape.
Power drills and power screwdrivers are battery powered or corded tools used to drive screws, among other things. They are required when the project requires many screws or the materials being attached are hard to penetrate. Power or electric screwdrivers are more lightweight than drills and are easier to maneuver, but they are less powerful and therefore less versatile.

Wrenches
Wrenches are hand tools used to apply torque, usually by gripping the outside of the bolt, nut or screw with relative specificity.

Types of Wrenches
Image
Tool Variation
Description & Uses




Crescent or adjustable wrench
Jaw diameter can be adjusted by turning the threaded worm to engage the corrugated edge of the non-fixed jaw. Crescent wrenches are highly versatile.



Pipe wrench
With serrated and adjustable jaws, the F-shaped pipe wrench is sturdy and commonly used for metal pipes.



Lug wrench
Used to remove or replace lug nuts on cars, lug wrenches are either L-shaped (with a socket on one end) or X-shaped (with
4 different sockets).



Allen wrench or Allen key
Used to apply torque to screws with a hexagonal recess in their head, Allen wrenches are L-shaped and have a hexagonal cross-section. They usually come in sets of various sizes.



Box-ended wrench
The closed loops at either end of the box wrench can be used for square or hexagonal bolts, and the (sometimes present) raised ends allow for gripping of recessed nuts or bolts. The two ends are slightly different sizes. They usually come in sets of various sizes.



Open-ended wrench
A very common type of wrench, open-ended wrenches have U-shaped openings at each end, and the ends are slightly different sizes. The open ends are more likely to round the edges of a nut or bolt than closed ends. They usually come in sets of various sizes.



Combination wrench
A combination of box-ended and open-ended wrenches, combination wrenches have an open and a closed end. They usually come in sets of various sizes.


Ratcheting wrench

At least one end of the ratcheting wrench contains a ratcheting device so that loosening or tightening doesn't require a complete circular motion or removing and resetting the wrench if something is in the way. These wrenches are helpful in tight spaces.



Socket wrench
Socket wrenches have a drive (the square-shaped fitting) attached to a ratchet on one end; various sockets can be attached to the drive to accommodate different size bolt heads. Sockets come in sets of various sizes.



Torque wrench
Manual and digital torque wrenches help prevent overtightening because they can be calibrated in accordance with manufactured specifications. These are commonly used in automotive work, among other things.
Wrench sizes for sets come in standard and metric, and size-range and specificity depend on the trade or project for which they are used. Common metric wrench sizes start at 4 millimeters (mm) and increase by 1 mm increments; common standard wrench sizes start at

 of an inch and increase by

" increments.

Like other wrenches, Allen wrenches come in fractional inch and metric sizes.

Socket sizes depend on the drive size, which is the square-shaped fitting on the ratchet at the end of the socket wrench.

The larger the drive, the more torque it can handle, therefore the sockets will be larger. The most common drive sizes are

 inch,

 inch, and

 inch.

Impact Tools
Impact drivers operate much like power drills or power screwdrivers, but they sense when additional torque is needed and internally employ a spring, hammer, and anvil to provide more rotational force.
Because of the additional torque, drill bits must have a hex shank, meaning the end of the bit inserted into the chuck (the drill's specialized clamp used to hold bits) must be hexagonal. Hex shanks are designed to withstand the stress of impact drivers. An example of when an impact driver might be necessary is when attempting to remove a screw that has rusted into place. They can be cordless with a battery or powered by an air compressor.
Impact wrenches use sockets (like the socket wrench) to remove stubborn nuts or bolts with the same spring, hammer, and anvil mechanism as impact drivers. They can be cordless with a battery or powered by A. air compressor pressurizes gas by reducing its volume, therefore converting power from a motor or an engine into pressurized air. They can be used to power pneumatic tools such as nail guns or impact wrenches and to air up tires.

Nuts, Bolts & Washers
A nut is a piece of hardware with a threaded hole and a typically hexagonal perimeter used in conjunction with a bolt; a bolt is a threaded rod with a head capable of being securely grasped. Together, a nut and a bolt are used to fasten multiple parts together. Washers are used when the hole through which the bolt passes is too large than the bolt head or the nut or when the force of the nut-bolt load needs to be more widely distributed; they are flat, typically circular plates with circular holes in the center. The outside edge should be larger than the holes passing through the pieces to be attached; the hole in the middle of the washer should be just large enough for the bolt to pass through.

Fastening Tools

Riveting Tools
Riveting is the process of joining plates of metal by use of rivets, which are short metal pins with a head and a stem (may be solid or hollow) that act as mechanical fasteners. Once passed through both metal sheets by drilling, placing, or punching, the rivets are smashed or pounded so as to flatten the head and expand the stem to complete the rivet joint. 
Rivets support tensile loads (force that occurs in opposite directions along the same axis) and shear loads (force that produces sliding, which is a failure in the plane parallel to direction of force), and the most common modern applications include: residential gutter construction, HVAC duct work, and aircraft manufacturing.



Retaining Rings
Retaining rings are a class of hardware used to reduce motion by stretching or compressing between mating pieces by fitting either on the inside of the exterior component or around the outside of the interior component.  Common variations include:
Circlip rings allow axial rotation while preventing lateral motion by snapping into a groove or onto a shaft.
Grooveless rings do not require a groove to function properly and often have a low profile.
Spiral rings are coiled into a groove and allow flexibility.
Beveled rings provide are specifically beveled to provide a rigid, sturdy joint when complementary ends are locked.
Bowed rings have one central tab and two projecting tabs so they function like a spring.

Soldering Tools
Soldering is the process of melting solder (a metal alloy commonly made of lead and tin) to create a joint between two different metals without melting either of them; this process requires applying heat at roughly 600-840°F. Solder comes as wire with common diameters of 0.032 and 0.062 inches, and it can be purchased with or without lead as part of the alloy. Soldering is commonly used to connect components on electronic circuit boards.
Soldering irons are hand tools used to apply heat to melt solder.
Soldering guns are heavier than soldering irons, but they heat and cool more quickly. They are used when soldering stained-glass windows and in heavy electronics.
A soldering station allows precise temperature adjusting for soldering irons and include other safety features such as temperature sensors and password protection, depending on the device.
A solder sucker or de-soldering pump is used to removed excess solder or to correct mistakes when soldering, even after the solder has solidified.

Welding & Welding Tools
Welding is the process of fusing two metals into one by melting the base metal (material to be welded or cut) through use of extreme heat (6500°F) and sometimes other metals or gases, depending on the welding method.
Goggles, a helmet (auto-dimming is best), gloves, and long sleeves should be worn while welding to protect from heat and radiation. Never look at the welding arc with the naked eye; this could cause permanent eye damage.
Common arc welding processes include: Tungsten inert gas (TIG) welding, flux-cored arc welding (FCAW), stick welding, and metal inert gas (MIG) welding.

Common Welding Terminology & Tools
A cutting torch is a tool that uses gas to pre-heat and cut metal.
Electrodes in welding refer to the various current-conducting metals used between the electrode holder/stinger and welding arc.
Flux is a cleaner used before welding or soldering to dissolve oxidation (rust); it can also be used during high-temperature welding to prevent oxidation.
External shielding gases are inert or semi-inert gases that protect the welding arc are molten weld from atmospheric contamination.
Slag is the solidified byproduct of some arc welding processes after the area cools.
A stinger or electrode holder is an insulated clamp that holds the electrode securely in position.
A welder or welding machine is the power source for the electrical current and heat source.
The welding arc is the discharge of electrons between the electrode and the base metal.

Gripping Tools

Pliers
Pliers are a class of hinged hand tool with handles and specialized jaws used especially for gripping and pulling. There are many different types of pliers, including:

Types of Pliers




Slip Joint Pliers
Highly versatile, the adjustable fulcrum allows the corrugated jaws to lock at varying widths.



Needle Nose Pliers
Elongated, often corrugated jaws allow for increased precision when bending and shaping wire.



Bent Nose Pliers
A variation of needle nose pliers with bent jaws, they are used for delicate tasks or working at difficult angles.



Crimping pliers
Specialized jaws allow for breaking plastic coating on wire and crimping wires together; this makes them ideal for telecommunications technicians.



Diagonal pliers (Wire cutters)
Acutely angled jaws enable cutting of wire and nails. 



Tongue and Groove Pliers (Channel Locks)
Various grooves on the upper jaw allow for an adjustable, locking fulcrum and a highly versatile tool.

Clamps
Clamps are devices used to secure objects together tightly for woodworking, plumbing, and countless other tasks. Clamps are specialized, and there are many common varieties, including:

Types of Common Clamps



C-clamp or G-clamp
The screw section is used to increase and decrease jaw-width and applied pressure of this very common clamp.

Pipe clamp
This clamp has jaws that form a circle so as to be fit around a pipe.


Hose clamp

An adjustable, circular band allows for tightening over a hose fitting to prevent leakage of fluid.



Bar clamp, F-clamp, speed clamp
The upper jaw is attached to a long bar, and the lower jaw can be adjusted to varying widths making it ideal for holding larger projects.



Spring clamp, pinch clamp, hand clamp
Built like pliers, jaws are usually padded and pressure originates from a spring, making it ideal for stabilizing while glue sets.



Toolmakers parallel jaw clamp
Double, parallel screws likewise hold the jaws parallel for maximum stability.



Bench clamp
A clamp built to be mounted on a workbench.

Vise-Grips
Vise-grips (which can also be spelled vice-grips), also known as locking pliers, are part clamp and part pliers. With handles, corrugated jaws, and a fulcrum between the two like pliers, they can also be locked into a clamped position. A lever in one of the handles allows for the release of the clamping action.
Vise-grips can be used as clamps, pliers, wrenches, and more; their versatility makes them useful for most trades and projects.



Cutting Tools

Manual Saws
A saw is a hand tool used to cut wood, metal, pipe, or other materials with a serrated edge using a back-and-forth motion. Different saws have specialized blades and handles for different jobs, including:

Hand Saws




Hand saw, rip cut saw, ripsaw
With a long, flexible, slightly tapered bade and sharpened, relatively widely set teeth, the hand saw is common in framing and other woodworking jobs. Can be used to roughly rip wood (cut wood with the grain).



Back saw, tenon saw
A square, thin blade has a reinforced upper edge and small teeth are set close together, making it ideal for straight, fine cuts. 



Bow saw
Shaped like a bow, the narrow blade with jagged teeth is used commonly to prune or trim trees.





Crosscut saw, lumberjack saw
Large teeth sit on the curved edge of a thick blade made for large, rough cuts of wood. Traditional forms have two handles so that two people can work together with one tool; common versions designed for one person have one handle with an extra sometimes placed on the back of the leading edge. 


Hacksaw
Very common and ideal for metalworking and cutting pipes, the blade has hard teeth.


Coping saw
Good for precision and intricacy, the thin blade is held tight by the frame and is used commonly for cutting curves in wood.


Keyhole saw, pad saw, jab saw, drywall saw
The blade is dagger shaped and most commonly used to cut small circles or odd shapes in drywall.

Powered Saws
Powered saws are specialized cutting tools that can be hand-held, stand-alone, or mounted on a work surface in order to cut various surfaces including wood, plastics, metal, and masonry.

Types of Common Power Saws



Chainsaw
Used for felling or trimming trees, chainsaws have a continuous band as a chain of specialized teeth that feeds around a metal bar and is ideal for ripping and cutting wood.


Band saw
Stationary or portable, a continuous band us used to make cuts that are intricate, though relatively shallow.



Circular saw, buzz saw, Skilsaw
The most common type of power saw, circular saws have a circular blade with teeth around the edge; specialized blade materials can be used to cut wood, metal, stone, and plastic. They are easily portable and can be used to rip (cut wood with the grain) or cross cut (cut perpendicular to the grain) wood.


Miter saw
A miter saw is a circular saw that can be mounted to a work bench, and its blade can make straight (90°) cuts or be locked at an angle to make highly specific cuts (commonly the 45° cut for making corners in wood trim).


Table saw
A table saw is a circular blade mounted in the middle of a table; wood (or other materials, depending on the makeup of the blade) is fed into to the blade in order to make the cut.



Jigsaw, saber saw
A narrow, easily maneuverable blade on a hand-held jigsaw allows for easy cutting of non-straight details and curves.


Reciprocating saw, Sawzall
Frequently used in construction and demolition, the reciprocating saw can cut both nails and wood, as well as plastics, bricks, and tiles.


Oscillating saw, oscillating multi-tool
Certain blade attachments change the functionality of the oscillating saw so that it can grind, scrape, or remove grout or caulk.
Its saw form utilizes a serrated blade that oscillates side to side; this design allows for cuts that plunge straight into the work surface without requiring an approach from the side or drilling a starter hole first.

Drilling Tools
Drilling tools cut new, circular holes in wood, metal, plastic, or other materials using bits, which are specialized tips that both cut and remove material as they move.
Common drill bits used for wood are characterized by a spiral-shaped blade with recessed flutes that make up the body of the bit and a shank, which feeds into and is held by the radially gripping chuck of the drill.  Drills are most commonly hand-held, but some can be mounted on a work bench or can stand on the floor; impact varieties also exist, which sense when additional torque is needed and internally employ a spring, hammer, and anvil to provide more rotational force.


Drill bit

Boring Tools
Common in machining, a boring bar is used in conjunction with a lathe following the drilling process to bore a workpiece
(enlarging an existing hole). A lathe is a machine tool that rotates a workpiece radially in order to sand, cut, drill, bore, and more. A boring bar is used in conjunction with a lathe to bore a pre-drilled hole into a workpiece to exact specifications. Line boring is when the boring bar is supported on both ends and the hole being enlarged must pass completely through the workpiece; back boring can be used for blind holes, which do not pass completely through the workpiece, with only one end of the boring bar fixed and supported, and it can be used for holes that pass all the way through the workpiece.

Surface Preparing & Finishing Tools

Planes
Planing is the woodworking process of smoothing, shaping, flattening, and straightening the surface of a wooden workpiece. Hand planers are the hand-held, manual tools traditionally used for this task; they are still used for small jobs such as slightly reshaping a door that sticks. However, power planers are used commonly to handle bulk jobs of adjusting board thickness or flatness, such as planing boards so that they are uniform for a building project, repurposing old lumber, or downsizing larger dimensional lumber into smaller, custom or more expensive pieces.

Files and Rasps
Files and rasps are manual, hand-held tools used for removing material from workpieces, most commonly of wood or metal.
Files produce a finer finish but cut more slowly than rasps. They can be single cut, with parallel ridges, or double cut, with two sets of parallel ridges set at an angle to each other; double cut files are rougher on a workpiece than single cut. Files come in four grades from smoothest to coarsest: smooth, second cut, bastard, and coarse.
Mill files are used to sharpen metal blades.
Rasps have raised teeth instead of ridges like a file, and they have various levels of coarseness: wood (the roughest), cabinet, and patternmaker (the smoothest).

Grinders
Grinders are powered, hand-held tools used for cutting, rough and fine shaping, smoothing, brushing, and polishing many different types of materials including wood, metal, stone, and plastic. They can sometimes be used for sanding jobs, whereas sanders cannot be typically be used for grinding jobs. 
Angle grinders are the most common form of grinders and are highly versatile. They can be used to clean metal (with the wire brush attachment); cut metal bolts (with the metal cutoff wheel attachment); cut masonry (with the diamond wheel attachment); and sharpen blades (with the grinding wheel).
Belt grinders can be used to finish surfaces and sharpen metal blades, among other things, using an abrasive belt.
Bench grinders can be mounted on a work bench and are used for grinding off large amounts of material or rust, sharpening metal blades, buffing and polishing surfaces, and cutting wood and other hard materials.

Sanders
Sanding is the process of smoothing a surface, commonly wood or metal, using an abrasive material such as sandpaper. Sandpaper comes in varying grit levels, the higher the number, the finer the sandpaper grit. Fine-grit sandpaper should be used for more detailed jobs, such as the final sanding step before staining wood.
Sanding blocks are hand-held, manual tools used to prevent high spots and ridges on the wood surface, and they are useful when a powered sander might do damage to the project. Removable sandpaper is attached to the side of the block opposite to where it is handled.
Orbital sanders (also known as palm sanders or circular sanders) are hand-held, powered tools that vibrates the square-shaped sanding pad in small, circular motions. They are relatively gentle and lightweight and work better for delicate projects than heavy ones. Random orbital sanders operate the same way, but their sanding pads are round, thus eliminating the minor scarring that can happen with the square-shaped pads of an orbital sanders.
Some sanders utilize a sanding belt, such as the belt sander and the file sander, which has a narrower belt used for fitting into small spaces.