Interior Corners

• 1). For interior corners, where the wall does not go out into the room, place one piece of cardboard against each wall and up to the corner. If the corner is 90 degrees, each piece of cardboard will be snug against both walls. If there is any gap, try to get the pieces of cardboard as far into the corner as possible, while keeping them flat. Draw the outline of the top piece of cardboard on the bottom piece. This will give you the angle at the corner.
  
  
• 2). Use the angle gauge on the miter saw to measure the angle of the corner. The miter saw should be off and unplugged. Place one edge of cardboard that was against the wall against the backstop. The edge of the other piece of cardboard that was against the other wall should be lined up to the cutting angle of the saw. Make sure the outline is still lined up while determining the angle.
  
  
• 3). Cut the moulding at exactly one half of the angle of the corner using the miter saw. The moulding should be cut inward, so that the face side is shorter than the back side.
  
  

Exterior Corners

• 1). Exterior corners are corners that point out into the room. Place one piece of cardboard along where the moulding is going and sticking out past the corner. Place the other piece of cardboard along the other edge overlapping the first piece of cardboard. Use the pen to outline the top piece on top of the bottom piece.
  
  
• 2). Place the bottom piece of cardboard on the miter saw with the overlap line close to the cutting angle. Place the second piece of cardboard on top of the first and line up the overlap line with one side. The opposite side will be at the exact same angle to the backstop as the corner. Line up the cutting edge with the side of the top piece of cardboard. Divide the angle in half to get the cut angle.
  
  
• 3). Use the miter saw to cut the moulding so that the outside-facing edge is longer than the inside edge.