A chainsaw (or chain saw) is a portable mechanical saw, powered by electricity, compressed air, hydraulic power, or most commonly a two-stroke engine. It is used in activities such as tree felling, limbing, bucking, pruning, by tree surgeons to fell trees and remove branches and foliage, to fell snags and assist in cutting firebreaks in wildland fire suppression, and to harvest firewood. Chainsaws with specially designed bar and chain combinations have been developed as tools for use in chainsaw art. Specialist chainsaws are used for cutting concrete.
The circular saw is a metal disc or blade sometimes with saw teeth on the edge as well as the machine that causes the disk to spin. It is a tool for cutting wood or other materials and may be hand-held or table-mounted. It can also be used to make narrow slots (dados). Most of these saws are designed with a blade to cut wood but may also be equipped with a blade designed to cut masonry, plastic, or metal. There are also purpose-made circular saws specially designed for particular materials. While today circular saws are almost exclusively powered by electricity, larger ones, such as those in “saw mills”, were traditionally powered by water turning a large wheel.
A miter saw (also spelled mitre) is a saw used to make accurate crosscuts and miters in a workpiece. A power miter saw, also known as a chop saw or drop saw, is a power tool used to make a quick, accurate crosscut in a workpiece. Common uses include framing operations and the cutting of molding. Most miter saws are relatively small and portable, with common blade sizes ranging from eight to 12 inches.
The miter saw makes cuts by pulling a spinning circular saw blade down onto a workpiece in a short, controlled motion. The workpiece is typically held against a fence, which provides a precise cutting angle between the blade and the longest workpiece edge. In standard position, this angle is fixed at 90°.
A primary distinguishing feature of the miter saw is the miter index that allows the angle of the blade to be changed relative to the fence. While most miter saws enable precise one-degree incremental changes to the miter index, many also provide “stops” that allow the miter index to be quickly set to common angles (such as 15°, 30°, 45°, or 75°).
There are several types of power miter saws:
- A standard miter saw has a fixed vertical pivot with rotating cutting table allowing horizontally angled cuts while the blade always remains vertical.
- A compound miter saw has a rotating vertical pivot allowing the cutter head & blade to be tilted sideways in addition to the horizontally rotating table. This allows vertical & horizontal angled cuts as well as cuts angled in both planes.
- A sliding compound miter saw is a compound miter saw with horizontal sliding arms for the cutter head allowing much wider cuts.
- A dual compound miter saw is like a sliding compound miter saw, but its blade and motor can tilt both left and right. This provides more flexibility for cutting complicated angles such as required for crown molding.
A table saw or sawbench is a woodworking tool consisting of a circular saw blade, mounted on an arbor, that is driven by an electric motor (either directly, by belt, or by gears). The blade protrudes through the surface of a table, which provides support for the material, usually wood, being cut.
In a modern table saw, the depth of the cut is varied by moving the blade up and down: the higher the blade protrudes above the table, the deeper the cut that is made in the material. In some early table saws, the blade and arbor were fixed, and the table was moved up and down to expose more or less of the blade. The angle of cut is controlled by adjusting the angle of blade. Some earlier saws angled the table to control the cut angle.
A bandsaw is a power tool which uses a blade consisting of a continuous band of metal with teeth along one edge to cut various workpieces. The band usually rides on two wheels rotating in the same plane, although some small bandsaws have three wheels. The saw may be powered by wind, water, steam, gas engine, electrical motor or animal power. Bandsawing produces uniform cutting action as a result of an evenly distributed tooth load. Bandsaws are used for woodworking, metalworking, or for cutting a variety of other materials, and are particularly useful for cutting irregular or curved shapes, but can also be used to produce straight cuts. The radius of a curve that can be cut on a particular saw is determined by the width of the band and its lateral flexibility.
A reciprocating saw is a type of saw in which the cutting action is achieved through a push and pull reciprocating motion of the blade.
The term reciprocating saw is commonly assigned to a type of saw used in construction and demolition work. This type of saw, also known as a recipro saw, Sabre Saw, or Sawzall (a trademark of the Milwaukee Electric Tool Company) has a large blade resembling that of a Jigsaw and a handle oriented to allow the saw to be used comfortably on vertical surfaces. The typical style of this saw has a foot at the base of the blade, also similar to a jigsaw. The user rests this foot against the surface being cut so that the tendency of the blade to push away from or pull towards the cut as the blade travels through its cycle can be countered.
Designs range widely in power, speed, and features, from less powerful portable, handheld models that are usually shaped like a cordless drill, to high-power, high-speed, corded models. Modern reciprocating saws almost all have variable speed, either through trigger sensitivity or through a dial. Another feature that has become important to the way these saws are used is the inclusion of an orbital action. The action consists of oscillating the traversed reciprocation in up and down fashion (perpendicular to the motion of cut) causing the tip of the blade to move in an oval pattern, up and down as well as back and forth. This feature is primarily for wood, allowing quick cuts.
The reciprocating saw is a popular tool used by many window fitters and construction workers. Reciprocating saws have many uses; here it is cutting through hard-to-remove nails in a staircase.
The term reciprocating saw (or oscillating saw) is also applied generically to any saw which cuts with a back and forth motion. These include:[custom_list style=”list-9″]
- Sabre Saw
- Rotary Reciprocating Saw
Powered Reciprocating tools are also found in surgery and dental surgery, where they are used in operations that require cutting or grinding of bone.
An abrasive saw, also known as a cut-off saw or metal chop saw, is a power tool which is typically used to cut hard materials, such as metals. The cutting action is performed by an abrasive disc, similar to a thin grinding wheel. The saw generally has a built-in vise or other clamping arrangement, and has the cutting wheel and motor mounted on a pivoting arm attached to a fixed base plate.
They typically use composite friction disk blades to abrasively cut through the steel. The disks are consumable items as they wear throughout the cut. The abrasive disks for these saws are typically 14 in (360 mm) in diameter and 7⁄64 in (2.8 mm) thick. Larger saws use 410 mm (16 in) diameter blades. Disks are available for steel and stainless steel.
A backsaw is any hand saw which has a stiffening rib on the edge opposite the cutting edge, allowing for better control and more precise cutting than with other types of saws. Backsaws are normally used in woodworking for precise work, such as cutting dovetails, mitres, or tenons in cabinetry and joinery. Because of the stiffening rib, the backsaws are limited in the depth to which they can cut. Backsaws usually have relatively closely-spaced teeth, often with little or no set.
Different types of backsaw include:[custom_list style=”list-9″]
- Mitre saw — often referred to a large backsaw (20-30 inches or 60-90 cm) used either in a wooden mitre box or in a metal frame which allowed cutting mitres of any specified angle. Note that not all mitre saws are backsaws, and the electric mitre saw (or chop saw) has taken its place today.
- Tenon saw, or often just backsaw — a midsized backsaw used to cut tenons or in a mitre box. The saw derives its name from its use in the cutting of tenons for mortise and tenon joinery. Tenon saws are commonly available with rip-filed teeth for rip cutting and cross-cut for cutting across the grain. Teeth are relatively fine, with 13 teeth per inch being a common size for the saw.
- Sash saw — name that seems to have been used in the 18th and 19th century for a smaller tenon saw, used in fabricating window sashes. The term is also used currently to refer to a thin, flexible saw used to free sashes that have been painted shut.
- Dovetail saw — a small backsaw used to cut dovetails. Although most dovetail saw teeth are set for cross-cutting, a rip saw tooth pattern is more efficient. These saws will usually have a higher number of teeth per inch (around 15 T.P.I.) with teeth sharpened to favor ripping operations and set to leave a narrow kerf.
- Gent’s saw or Gentleman’s saw (rare) — a small dovetail saw with a straight turned handle, rather than an open one typical of most saws. The name seems to have arisen from its use by the nineteenth century dilettante who would now be called a hobbyist but it is hard to find a nineteenth century reference to it. For example, in the section on tools in Every Man his own Mechanic (1881) (816pp), tenon, dovetail and sash saws are listed as a group but there is no mention of a gent’s saw. It is adapted for use in making joints in very small woodwork such as that in some musical instruments, dolls’ furniture or other model-making. Its distinguishing features are its small size and turned handle.
- Razor saw — A very small backsaw having very finely-pitched crosscut teeth, often with no set. The Razor saw is used by hobbyists, notably Model aircraft, Model boat, and Model railroad enthusiasts. Razor saws typically use disposable blades (or are occasionally designed to be completely disposable), since their teeth are so small as to be impractical to re-sharpen. Unlike most other types of backsaws, razor saws are also frequently used to cut plastics and soft metals.
- Dōzuki — a Japanese backsaw, used for centuries by carpenters and cabinetmakers in Japan. Although this saw does not share an ancestry with the other backsaws in this group, the concept is the same. Like most Japanese saws, the dōzuki cuts on the pull stroke, allowing for much straighter and narrower cuts than those achieved with push-stroke saws. This is due to tension on the blade during the cut (versus compression for a western saw), so less thickness is required to keep the saw blade straight.
A drill or drill motor is a tool fitted with a cutting tool attachment or driving tool attachment, usually a drill bit or driver bit, used for drilling holes in various materials or fastening various materials together with the use of fasteners. The attachment is gripped by a chuck at one end of the drill and rotated while pressed against the target material. The tip, and sometimes edges, of the cutting tool does the work of cutting into the target material. This may be slicing off thin shavings (twist drills or auger bits), grinding off small particles (oil drilling), crushing and removing pieces of the workpiece (SDS masonry drill), countersinking, counterboring, or other operations.
Drills are commonly used in woodworking, metalworking, construction and do-it-yourself projects. Specially designed drills are also used in medicine, space missions and other applications.
There are many types of drills; some are powered manually, others use electricity (electric drill) or compressed air (pneumatic drill) as the motive power, and a minority are driven by an internal combustion engine (for example, earth drilling augers). Here are a few:[custom_list style=”list-9″]
- Pistol-grip (corded) drill
- Hammer drill
- Rotary hammer drill
- Cordless drills
- Drill press
- Geared head drill press
An angle grinder, also known as a side or disc grinder, is a handheld power tool used for cutting, grinding and polishing.
Angle grinders can be powered by an electric motor, petrol engine or compressed air. The motor drives a geared head at a right-angle on which is mounted an abrasive disc or a thinner cut-off disc, either of which can be replaced when worn. Angle grinders typically have an adjustable guard and a side-handle for two-handed operation. Certain angle grinders, depending on their speed range, can be used as a sander, employing a sanding disc with a backing pad or disc. The backing system is typically made of hard plastic, phenolic resin, or medium-hard rubber depending on the amount of flexibility desired.
A bench grinder is a type of benchtop grinding machine used to drive abrasive wheels. A pedestal grinder is a larger version of a bench grinder that is mounted on a pedestal, which is bolted to the floor. These types of grinders are commonly used to hand grind cutting tools and perform other rough grinding.
Depending on the grade of the grinding wheel it may be used for sharpening cutting tools such as lathe tools or drill bits. Alternatively it may be used to roughly shape metal prior to welding or fitting.
A wire brush wheel or buffing wheels can be interchanged with the grinding wheels in order to clean or polish work-pieces.
Grinding wheels designed for steel should not be used for grinding softer metals, like aluminium. The soft metal gets lodged in the pores of the wheel and expand with the heat of grinding. This can dislodge pieces of the grinding wheel.
A belt sander is a machine used to sand down wood and other materials for finishing purposes. It consists of an electrical motor that turns a pair of drums on which a seamless loop of sandpaper is mounted. Belt sanders can be either hand-held, where the sander is moved over the material, or stationary (fixed), where the material is moved to the sanding belt. Stationary belt sanders are sometimes mounted on a work bench, in which case they are called bench sanders. Stationary belt sanders are often combined with a disc sander.
Belt sanders can have a very aggressive action on wood and are normally used only for the beginning stages of the sanding process, or used to rapidly remove material. Sometimes they are also used for removing paints or finishes from wood. Fitted with fine grit sand paper, a belt sander can be used to assure a completely smooth surface.
Stationary belt sanders are used for removing non-ferrous metals, such as aluminum. Non-ferrous metals tend to clog grinding wheels, quickly making them useless for grinding soft metals, while belt sanders continue to grind without clogging. This is because the small grooves in the sand paper are opened up as they go around the arc of the drive wheel.
Belt sanders can vary in size from the small hand-held unit shown in the illustration to units wide enough to sand a full 4-by-8 foot sheet of plywood in a manufacturing plant. Some belt sanders can be as tall as 1.2 metres and 70 centimetres long.
Sanding wood produces a large amount of sawdust. Therefore, belt sanders employed in woodworking are usually equipped with some type of dust collection system. It may be as simple as a cloth filter bag attached to a portable sander or a large vacuum system to suck dust particles away into a central collector.
Slack belt sanding is commonly used in the manufacturing process of guitars and other medium-sized wooden objects. It is a long sanding belt which runs slackly over the object. The machinist then exerts pressure to it to sand down specific areas. It is a very precise process which takes great skill and accuracy.
Gas Metal Arc Welding (GMAW), sometimes referred to by its subtypes Metal Inert Gas (MIG) welding or Metal Active Gas (MAG) welding, is a semi-automatic or automatic arc welding process in which a continuous and consumable wire electrode and a shielding gas are fed through a welding gun. A constant voltage, direct current power source is most commonly used with GMAW, but constant current systems, as well as alternating current, can be used. There are four primary methods of metal transfer in GMAW, called globular, short-circuiting, spray, and pulsed-spray, each of which has distinct properties and corresponding advantages and limitations.
Originally developed for welding aluminum and other non-ferrous materials in the 1940s, GMAW was soon applied to steels because it allowed for lower welding time compared to other welding processes. The cost of inert gas limited its use in steels until several years later, when the use of semi-inert gases such as carbon dioxide became common. Further developments during the 1950s and 1960s gave the process more versatility and as a result, it became a highly used industrial process. Today, GMAW is the most common industrial welding process, preferred for its versatility, speed and the relative ease of adapting the process to robotic automation. The automobile industry in particular uses GMAW welding almost exclusively. Unlike welding processes that do not employ a shielding gas, such as shielded metal arc welding, it is rarely used outdoors or in other areas of air volatility. A related process, flux cored arc welding, often does not utilize a shielding gas, instead employing a hollow electrode wire that is filled with flux on the inside.
Gas Tungsten Arc Welding (GTAW), also known as Tungsten Inert Gas (TIG) welding, is an arc welding process that uses a nonconsumable tungsten electrode to produce the weld. The weld area is protected from atmospheric contamination by a shielding gas (usually an inert gas such as argon), and a filler metal is normally used, though some welds, known as autogenous welds, do not require it. A constant-current welding power supply produces energy which is conducted across the arc through a column of highly ionized gas and metal vapors known as a plasma.
GTAW is most commonly used to weld thin sections of stainless steel and non-ferrous metals such as aluminum, magnesium, and copper alloys. The process grants the operator greater control over the weld than competing processes such as shielded metal arc welding and gas metal arc welding, allowing for stronger, higher quality welds. However, GTAW is comparatively more complex and difficult to master, and furthermore, it is significantly slower than most other welding techniques. A related process, plasma arc welding, uses a slightly different welding torch to create a more focused welding arc and as a result is often automated.