Example: If it’s an 80 degree corner and you have a 45 spring angle, you then set the miter at 40.12 deg. If you are renting a compound miter saw for this project, it is worth asking if you can also rent the crown stop attachments. To join two pieces in a straight run, use a butt joint Wherever one piece of molding joins another, coat the adjoining face of the second piece with joint compound before you press it into place. The crown spring angle is sprung by using the correct Dihedral Angle for the compound miter and bevel angle.
No glue should be used here since the stop would need to be relocated if a different sized molding were being cut. A love of fundamental mysteries led Chris Deziel to obtain a bachelor’s degree in physics and a master’s degree in humanities. Also, when you cut on the flat, outside corners are not always on the right, inside corners are not always on the left. We are planning on cutting the molding in position” using this Cut N Crown jig Now I just have to wait for it to arrive in the mail. When you have a sloped ceiling where crown piece No. 3 runs into a vertical wall (Fig.
You are having trouble because you are cutting the crown molding in the same fashion as you probably cut baseboard or window or door casing. I then take the definitively correct piece to the miter saw and play with all the possible positions until it will fit the saw cut. However, for larger crown I recommend installing a plywood backer board, which provides a solid nailing surface at any point along every wall.
However, if putting the good side down” tips the molding so it is not truly parallel with the saw table, then the compound angle you thought you correctly set will be thrown off and the joints won’t quite fit right. The chart at the end of this article lists the appropriate miter-bevel settings for both 52°/38° and 45°/45° Ceiling Wall Crown Moldings with angle-between-wall ranges of 67°-179°. Wear safety goggles to prevent splinters and other pieces of debris from getting into your eyes as you cut. Then set the saw to 90 degrees, align the blade to the point where the miter ends at the back of the molding, and cut off the triangle.
This allowed me to place the crown molding in the jig snug, which allowed me to focus on the cut as opposed to straining to hold the molding still. The bottom of the crown is next to the fence and the top will be cut so it is 0 inches long (makes a point). This makes it easy to find those odd degrees that are required for cutting your crown on the flat. Then you can glue the end cap to the main strip of molding before attaching to the wall and window trim. Once you have found the measurements and the corner you need, use one of the methods above to complete your cut.
Most measurements can be made by placing the stick of molding in place and marking it directly. You will notice in the video, that the cope I do won’t fit while it’s still clamped to the bench because the clamps have straightened out the crown while it’s being coped. I start with a corner, usually inside, and mark on a scrap the inside angle with an angle divider, look at a Stanley #30, mark down my lengths, go to all corners the same way, go cut my crown, and install it.
Whenever possible, nail the crown molding into wall studs and ceiling joists and use a pneumatic nail gun to save time and avoid the possibility of damage resulting from missed hammer blows. Cut the piece about 1/16 in. beyond the length mark and then shave off a bit if the piece is too long. It will calculate the angles you need based on the actual angle of the corner, so you won’t have to guess. If you have a shape that is not typical, send me an end view photo of your crown molding and I will be glad to advise you as to how to cut and mount it.
If the wall angle is slightly off, adjust the cuts on both molding faces equally by one degree at a time until you have a close-fitting joint (Image 4). This is easily done on a power miter saw, which can be adjusted to cut across a range of fractional angles. For this first piece, both ends will be squared off and cut at 90° (or a 0° angle on your saw) while the molding rests flat on your saw (on flat). From here, the ceiling angle will be relative to the angle of the crown (ie horizontal and not vertical).
I have also installed crown where either 38-52 or 45-45 angles were 90 degrees to each other making it impossible to get in miter box and position correctly. Doing so will give you practice and experience, allowing you to make a better cut when it actually counts. The line formed by the intersection of the cut-plane and the contoured surface of the molding is exactly where the coping cut needs to be. If the crown is cut at the same angle as the projection, the cope will fit every time. Divide this measurement by two and make your initial bevel cut according to this figure.
The other advantage is that you don’t need to know the spring angle of the crown. A: Yes, mitering crown molding does require cutting compound angles, Bill, but you don’t need a compound mitersaw to do it. Match it up where the back of the saw blade will hit your mark and go out from there, so that the mark is the shorter point of your cut. So each corner needs to be measured individually and that measurement must be accurate to get a tight-fitting miter.
The inside” pieces should always be cut to the left of the saw blade, while outside” ones are to be cut on the right – writing that down on the back of molding is also a good idea. Some carpenters prefer to install wood blocking against the wall and ceiling joint to serve as a secure nail base for the molding (Image 4). Use wood blocking if your molding is wider than 4-3/4 inches. You would make a steep angle cut into the moulding along this pencil line following the contour of the moulding. Coupled with that, the geometry of this type of molding makes it a little tricky to cut.
Note how the back of the crown molding does not touch the wall surface, just the small angled parts of the trim touch the ceiling and wall. Smooth out any caulk that squeezes from between the two pieces of molding before it has time to set. That’s because even though they may look square, many wall corners do not form perfect 90-degree angles. To ensure that the molding stays in place be sure nails are driven into wood framing at regular intervals across the wall and ceiling. The only difference is that the material will be on the other side of the blade, to make the matching cut.
When I cut crown I check every corner with a digital protractor so I can cut each corner to within about half a degree, but I have no clue how to calculate that difference into the cut angles on the flat. For an inside corner, don’t concern yourself with mitering the moulding, instead cope the crown moulding. Set the saw table at 35° right to cut the molding that will form the right inside and left outside corners, pieces C and D pictured here.
If the change in wall angle occurs at the same time, you must first bring the crown around the wall corner (ie. Two options that will calculate the compound miters from the spring angle for on-site work when cutting flat. Room’s are often crown moulded with manufactured plaster coving or ornate mouldings. Use the inside corner of a framing square to simulate the wall-ceiling junction. The main challenge in installing crown molding – or any type of molding – is getting the pieces cut to the right length and at the right angle.
I hold the proper pair up to the wall where I want to install my real molding, identify which piece I want to cut now and then put the rest back in my pocket. To glue the corner shift the molding to expose the end and use a small brush to apply a coat of wood glue to both pieces. This type of joint is preferred over a miter joint because wall corners are rarely perfectly square (90°) and a coped joint creates a tight-fitting seam regardless of the corner angle. Crown molding has small angled faces as well as a large flat spot on the back of the profiled face.
I like to have wide wings so I can clamp crown stops to them, so I can clamp a coping jig to them, so I can clamp a piece of trim or a 1x to the stand and use the stand and wings as a work center. Today, thanks to a new molding material, you can create the same effect with less skill than it takes to install wood molding. When I am working alone (or even when I’m not) I find it extremely helpful to install a support board just under where my molding will sit. Match up the samples in the corners such that the mouldings create a perfect corner.
To make their cuts, they angle the molding on the saw as if it was sitting against the wall and ceiling and make a 45 degree cut, like this…. Using a spare piece of trim, trace the contour of the molding on the mitered edge, and cut along the lines with a coping saw. Use the inside corner of a framing square to simulate the junction of your wall and ceiling.
Positioning the molding this way creates a hollow spot behind the molding, the same hollow spot that exists when the crown molding is in place up on the wall. Insert a piece of crown molding into the box with its bottom edge facing up. Hold it so that it’s angled against the bottom and side of the box in exactly the same way that it fits against the wall and the ceiling, and cut the end at a 45-degree angle. Use your crown molding templates to make sure you have set up you saw correctly. Tapping on the protractor button will display an image of a 360 degree protractor.