When it comes to making square, angled or beveled crosscuts, there may not be a more appropriate woodworking power tool than a miter saw. There are a number of different styles, from single to dual-bevel compound miter saws to sliding miter saws, with typically available with an 8-inch, 10-inch or 12-inch blade. Most sliding miter saws use one or more long travel bars or rails on which the sliding saw rides, but in some cases such as the Bosch GCM12SD Sliding Miter Saw use a set of matching elbow-like arms to allow the saw to slide without the requirement for additional space against the wall behind the body of the saw.
The concept behind a miter saw is relatively simple. The board to be crosscut is placed on the saw's table and against the extendable fence to keep the board square to the axis of the saw. The saw blade is then plunged down into the board to complete the cut. For a mitered cut, the saw can be angled up to 45-degrees to the left or the right before the cut is made. Most saws have detents (preset locked positions) at 0-degrees, which is square to the fence, as well as 15, 22.5, 30 and 45 degrees both to the left and the right. However, if you want to cut a unique angle without a preset detent, you can adjust the miter position to the desired angle and lock the position of the blade for repeated cuts of the desired angle.
Should a beveled cut be necessary, most miter saws can bevel the saw to the right with a floating angle adjustment mechanism that can be locked at any angle up to 45 degrees. On some models, the saw can also be beveled up to 45 degrees to the left as well. Where this comes in handy is in making compound cuts, with both a bevel and a miter for the same cut. This is especially vital when installing moldings such as crown molding.
To make a cut using a miter saw, no matter whether a bevel or a miter (or a combination of the two) is required, the principle is the same. First of all, measure the length of the cut and place a pencil mark on the top of the board against the back edge which will be held against the miter saw's fence. Then, position the board flat on the saw's table and firmly against the fence while lining up the pencil mark along the back edge of the board with the saw blade. Once the board is in position, hold the board firmly using your off hand (or if the saw is equipped with a hold down mechanism, use the hold down) to secure the board in place while you depress the trigger with the other hand. Then, with the saw blade at full speed, gently ease the blade into the board until the cut is complete. Keep the trigger depressed and raise the blade back to the starting position before releasing the trigger.
If you are using a sliding miter saw, the only difference in making a cut would be that if the board to be cut is wider than the blade can cut with a standard vertical motion, you can pull the saw forward (toward your body) before starting the motor. Then, after plunging the blade fully into the wood, you can push the motor forward, sliding the blade through the wide cut.
Some miter saws have extendable wings on either end of the saw table, that provide extended support for cutting long boards. However, in many cases, you may need to provide additional support for cutting very long boards. In that case, you can use sawhorses, roller supports or even a portable miter saw stand to support the extra long boards. This is far safer and more preferable than trying to balance the board on the miter saw and holding it with your off hand.
As for additional features to consider, some miter saws are equipped with a handy laser sighting system that projects a solid red line along the cut line that the blade will cut. This type of laser line marking system is very handy for positioning the board so that the cut will be accurate. If your saw is not equipped with a laser line marking system, there are aftermarket lasers available that align with the saw's arbor nut.
However, with practice, one can easily sight down the line of the blade to position the board without the need for the laser line. The lasers are accurate but can be difficult to see if using the saw outside in direct sunshine. Most miter saws have slits in the blade guard that allow the operator to see easily through the guard to align the pencil mark on the board with the saw blade.
Another thing to consider is using a dust collection system or a shop vacuum when using a miter saw. Most miter saws have a dust bag that can be removed and a dust collection hose connected to the housing. Using a vacuum hose will help to keep the cut line visible throughout the cutting operation.