Table saw - Definition

A table saw is the most common piece of large woodworking equipment. Because of its versatility, when only one piece of large woodworking machinery is owned, it will often be a table saw. The saw consists of a circular saw blade, mounted on an arbor, that is driven by an electric motor (either directly or by belt or gears). The blade protrudes through the surface of a table, which provides support for the material (usually wood) being cut.

Modern Features

In modern table saws, the depth of the cut is varied by adjusting the amount of the blade that protrudes above the table surface: 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.

Types of Table Saws

There are three general classes of table saws: benchtop table saws, contractor saws and cabinet saws.

• Benchtop table saws are lightweight and are designed to operate while sitting on a table or other support. They commonly have direct drive (no v-belt or pulleys) from an universal type motor. They can be lifted by one person and carried to the job location. These saws often have parts made of steel, aluminum and plastic and are designed to be compact and light.

• Contractor saws are heavier, larger and have an attached stand or base, often with wheels. The motor hinges off the rear of the saw and drives the blade via a single belt using a 1 to 2 hp (750 to 1500 W) induction type motor. This is the type often used by hobbyists and homeowners because standard electrical circuits are adequate and due to its low cost.

• Cabinet saws are heavy (using large amounts of cast iron and steel) to minimize vibration and increase accuracy. A cabinet saw is characterized by having a closed (cabinet) base. Cabinet saws usually have induction motors in the 3 to 5 hp (2 to 4 kW) range. For home use, this type of motor typically requires that a heavy circuit be installed (in the US, this requires a 220V outlet). The motor is enclosed within the cabinet and drives the blade with three parallel v-belts.

Additional Accessories

• Rip Fence: Table saws nearly always have a fence (guide) running from the front of the table (the side nearest the operator) to the back, parallel to the cutting plane of the blade. The distance of the fence from the blade can be adjusted, which determines where on the workpiece the cut is made. The fence is commonly called a "rip fence" referring to its use in guiding the workpiece during the process of making a rip cut.

• Miter Guage: The table has one or two grooves running from front to back, also parallel to the cutting plane of the blade. These miter slots (or miter grooves) are used to position and guide either a miter gauge(also known as a crosscut fence) or crosscut sled. The miter gauge is usually set to be at 90 degrees to the plane of the blade's cut, so as to cause the cut made in the workpiece to be made at a right angle. The miter gauge can also be adjusted to cause the cut to be made at a precisely controlled angle (a so-called miter cut).

• Crosscut Sled: A crosscut sled is generally used to hold the workpiece at a fixed 90 degree angle to the blade, allowing precise repeatable cuts at the most commonly used angle. The sled is normally guided by a runner fastened under it that slide in a miter slot. This device is normally shop made, but can be purchased.

• Tenon Jig: A tenon jig is a device that holds the workpiece vertically so cuts can be made across the end. This allows tenons to be formed. Often this is a purchased item, but it can be shop made.

• Stacked Dado: Saws made for the US market are generally capable of using a stacked dado blade set. This is a kit with two outer blades and a number of inner chip cutters that can be used to cut dados (grooves in the workpiece) of any width up to the maximum (generally 7/8 of an inch).

Safety Advice

Important things to remember when using a table saw are:

• Read all warning labels and the owner's manual before operating the saw.

• When the saw is not in operation, it is good practice to lower the blade below the table.

• Be sure the power is disconnected before performing maintenance on the saw.

• Use a push stick or other such safety device when making cuts that would otherwise require fingers to be near the blade.

• Never operate the saw in a way that your fingers are advancing into the path of the blade. Always be fully present and alert as this piece of equipment causes more serious injuries than anything else in the shop. Many experienced woodworkers know someone who has lost a finger.

• Keep the blade guard in place whenever possible. If you do not like the guard that came with the saw, it is possible to purchase aftermarket guards of various configurations. Note that one of the main functions of a typical blade guard is to act as a splitter, which helps prevent the cut in the wood from closing and pinching the back of the blade and kicking back.

• Wood being cut can be violently "kicked back". This can be due to advancing the wood in other than a straight line or because natural stresses in the wood cause the cut to close on the back of the saw blade. This can be strong enough to cause injury or embed the workpiece in the wall behind the operator. The use of the splitter that is part of the blade guard can reduce or eliminate this problem.

• Wear eye protection. It is good practice to also wear ear protection to prevent the steady loss of hearing that occurs when using power equipment without protection.

• The table saw must be adjusted so the blade is perfectly parallel with the fence and the miter slots. If it is not parallel, the workpiece can easily become pinched between the blade and the fence, inducing violent kickback and causing injury. The manufacturer of the table saw will very likely send a manual free of charge.

Avoiding Kickback

Kickback is caused when the blade catches the workpiece and violently throws it back to the rear of the saw, towards the operator. It can be thrown very hard and can injure the operator. It is not uncommon for the object to have high enough velocity to become embedded in a wall or to cause other damage or injury.

• Blade must be sharp and clean. Novices often do not recognize the importance of using a clean and sharp blade. Pitch buildup on a blade greatly increases friction and decreases the quality of the cut, causing burning. Pitch also increases the probability of kickback.

• Saw must be aligned. The blade must be adjusted so that it is parallel with the miter grooves and the rip fence. If the blade is out of parallel, it is possible for the workpiece to be pinched between the blade and the rip fence, which will cause violent kickback.

• Use the blade guard when possible. The blade guard on typical American market saws incorporates a spreader, which helps prevent the cut from closing on the back of the saw blade. Natural tension can exist in wood that causes the cut to close. Some blade guards have anti-kickback devices that allow only forward travel past the blade.

• Push the workpiece past the blade. Do not release a workpiece until it is past the blade and removed from the saw. Turn the saw off before removing small cut off pieces.

• Always maintain control. Do not execute a cut where you do not have complete control of the situation. Make sure there are no obstructions. Do not cut a workpiece that is too large to handle.

• Do not use the rip fence as a guide during crosscuts. If you need to make a series of equal length crosscuts, use a stop block in front of the blade so the workpiece is not in contact with the rip fence during the cut. It is easy for the workpiece to twist out of perpendicular at the end of the cut and thus get caught by the blade and thrown.

• Be careful about flaws in the wood. Cutting through a loose knot can be dangerous. Cutting a warped or twisted board along the rip fence is dangerous because is can get pinched between the fence and blade.