Table saws are ideally suited for ripping lumber, that is making long cuts with the grain of the wood. However, one common accessory (which typically is included with your purchase of a table saw), known as a miter gauge, can make the table saw just as useful for making cross-cuts (typically cutting a piece of wood to length, against the grain of the wood). Since a table saw's blade can be angled up to 45-degrees, and the miter gauge can be angled as well, the table saw can make compound cuts that are most often reserved for a compound miter saw or radial-arm saw.
What is a Miter Gauge?
A miter gauge consists of a long thin guide, which rides in the miter slot of your table saw (some band saws also have miter slots), and guides the miter gauge parallel to the blade. Attached to this guide is a half-moon shaped piece that pivots on its connection point to the guide. A locking mechanism then allows this pivoting section to be locked into any angle (from -45 degrees to 45 degrees). A board is placed against the flat section of the gauge and the entire assembly (miter gauge and board) is slid forward, allowing the saw blade to cut the end of the board at the prescribed angle.
Square Cross-Cuts with a Miter Gauge
The easiest cut to begin with is a square cross-cut, where the miter gauge is set to 90-degrees (based on the angle markings on the gauge), and the end of the board is cut square.
Although the angle settings on miter gauges are designed to be as accurate as possible, often they can be one or more degrees out of kilter. To check the accuracy of your gauge, set the gauge to 90-degrees (or 0-degrees depending on your gauge's markings), for a square cut that is perfectly perpendicular to the miter slot on your table saw), unplug your table saw's electrical cord and raise the blade as high as it will go.
Slide the gauge forward until it is in line with the front edge of the exposed, stationary saw blade (do not attempt this without first disconnecting the saw from the power source). Place one square edge of a 6-inch combination square against the saw blade, and the corresponding edge of the square against the flat, forward edge of the miter gauge. If the square aligns perfectly with both the blade and the gauge, then your gauge's settings are accurate. If there are any gaps between the square and either the blade or the gauge, adjust the angle of the gauge until they align perfectly, and tighten the locking mechanism.
To make a cross-cut, slide the miter gauge backwards (toward your body) to the front edge of the saw table, and place a board against the flat edge of the gauge. Make a pencil mark on the wood where you want to make the cross-cut, and align that mark with the saw blade (while keeping the board flat against the miter gauge). Then, turn on the saw, and guide the miter gauge (with the board still held securely against the gauge) forward and past the saw blade, completing the cross-cut. When the cut is completed, ease the board along the gauge away from the blade and slide the whole assembly back to the starting position before turning off the saw motor.
As with any operation with a table saw, always keep your hands well away from the table saw's blade.
Angled Cross-Cuts with a Miter Gauge
Angled cross-cuts are similar to square cuts, except that the miter gauge is set to an angle (of up to 45-degrees) before sliding the gauge and corresponding wood piece toward the blade to make the cut. When making an angled cut using the miter gauge, move the gauge a little bit slower than you did making a square cut, as the gauge's movement can tend to slide the board out of position as you move toward the blade. A small woodworking clamp can be used to secure the board to the gauge to hold it in place as you make the cut.
Of course, combination cuts can also be completed by setting both the angle of the miter gauge and the bevel of the saw blade to the desired angles before easing the gauge forward, completing the compound cut.
Specialty Cuts Using Jigs With the Miter Gauge
When cutting longer boards (of up to 4-feet in length), you may wish to secure a sacrificial strip of wood to the face of your miter gauge to provide added stability to the board being cut. Most miter gauges have a matching set of holes in the back through which you can drive a wood screw with a cordless drill to secure the sacrifical board.
Additionally, there are jigs that can be attached to a miter gauge to make specialty cuts. One such example is a box joint jig for making perfectly-matched box joints (or finger joints) using your table saw and a stacked dado blade set.
As mentioned above, cross-cuts on boards longer than four feet should probably not be attempted using a table saw and a miter saw. Not only are they too difficult to align accurately, but the saw table is usually too small to accommodate such a board safely.
Additionally, when making any kind of cross-cut with your miter saw, do not use your table saw's fence in conjunction with the miter saw. While it might seem logical to align the fence with the blade at the desired cut distance, then slide the butt end of the board against the saw and make the cut using the miter gauge, the board will have a high likelihood of binding against the fence, which is a dangerous kickback waiting to happen. Instead, either remove the fence or slide it well out of the way before attempting any cross-cuts (square or angled) using the miter gauge.
And of course, last but certainly never least, when doing anything in the woodshop, always wear protective safety gear, including safety glasses, hearing protection and appropriate clothing.