Mitered joints refer to the edges of wood beveled so two pieces fit together at a corner. Picture frames, crown molding and base boards are all examples of mitered corners. Many pieces of molding also have intricate curves, making mitered corners more of a challenge. With the right measurements and calculations you can miter corners like a pro.
Measure your angle. Mitered corners aren't always a perfect 90 degree angle, so measuring the angle is the most important step.
Take your measurement and bisect or divide the angle in half. Use a compass to measure the angle and then draw a line representing the half way mark between the two sides of the angle.
Set up your miter box saw. A miter box saw is a saw set in a box that moves to accommodate the angle you've drawn. Set the wood under the saw in the miter box and cut on the line drawn that represents the finished angle.
Repeat the cutting with your second piece of wood.
Use a planer to smooth the surface of each piece before trying to join it with glue or nails. This is essential to having a true fit for your corner. Often just the cutting alone doesn't get the angle perfect. Planing and finish sanding help make the fit just right.
If cutting angles is a frightening prospect for you, consider using a simpler method by cutting only one piece of trim at the angle and butting it into the straight piece on the other side. You won't have an actual miter, but it looks very similar when finished.