Cutting inside and outside crown molding corners are easy to cut. Make some small 90 degree test pieces for both corners. First, these test pieces help you make the proper cut. Remember on the inside corner, the longest side is the bottom of the molding. On outside corners, the top is the longest side of the molding. The crown molding must be placed upside down in the miter saw when making these cuts.
Helpful tip - take a piece of tape, place it on the saw table and mark it "Ceiling - Top of Molding". You can also make the power saw fence "Wall - Bottom of Molding."
These test pieces will help you understand how to cut crown molding correctly. Once you have mastered this, you can move on to the longer pieces for your crown molding project.
If you REALLY want to discover how to install Crown Molding, you need my
Crown Molding EBook or Installing Crown Molding DVD.