Ï»¿The advantage to cutting crown moulding using this method is that it does not require a bevel cut. As you can see above, the left side of the molding will actually need to be cut as a right inside corner since that is which side of the corner it resides on, while the right side of your molding will need to be cut as a left inside corner… again since that is which side of the corner it happens to reside on. If you don’t label your board appropriately, it’s easy to forget which is which when you are cutting.
As most trim carpenters will tell you, the most efficient method is to hold the molding in a position that reflects its final installed position while you cut it. To do that, you simply turn the molding upside down” and position it so that the edge that will meet the ceiling rests on the bed of the saw, and the edge that will be flat against the wall rests on the saw’s fence.
The only time I cut on-the-flat is when the crown is too tall to cut in-position, otherwise, I can cut more than twice as fast and with much better accuracy in-position, running round 87 degree and 92 degree corners, changing spring angles in mid- stream while installing crown on kitchen cabinets where the doors vary 1/4-3/8 in. from the ceilings, etc.
Mark the wall as level as you can at the base of the crown then place the bevel over the protractor to determine as close as possible the corner angle. To cut most commonly available crown mouldings, set the angle at 31.6 degrees and the bevel at 33.9 degrees. To make miter cuts for copes and outside corners, you have to lean the crown molding—tilted at exactly the correct angle—against the saw’s fence (Photo 11).
In order for this to happen, both pieces of crown molding need to match the measured angle of the corner, so both should be cut to an exact have of this measured angle. Bosch makes an electronic angle finder that allows you to place it in an inside or outside corner to read the true angel (not always 90%) and then it gives you the miter and bevel setting. The miter and bevel of the saw are set a the proper angle to cut the compound angle (this is a two dimensional angle sloped both vertically and horizontally.) for 38 degree crown the settings for a 90 degree corner is 31.6 for the miter and 33.8 for the bevel. Angle the saw by 30 degrees and shave off more wood from the back of the molding.
Your bevel will sit to the left and you will be keeping the material to the left of your cut, just as with the left inside corner cut previously. Now move your miter and blade tilt so that your saw blade will match the bevel cut on the crown molding template. The saw should be angled back into the wood slightly, to make the cut line stick out the farthest. Some people find it easier to cut crown molding using a compound miter saw because you can hold the molding flat against the saw table.