Yes, you can absolutely cut crown molding on a miter saw easily once you know the right setup. Many people think cutting crown molding is hard, but it is not. With the right steps, your miter saw becomes a powerful tool for this job. We will show you how to set up your saw for perfect crown molding cuts.
Choosing the Right Miter Saw for Crown Molding
Not all miter saws handle crown molding the same way. The type of saw you use affects how you make the cuts.
Compound Miter Saws vs. Sliding Compound Miter Saws
A standard compound miter saw works well. However, a sliding compound miter saw offers more capacity. This extra room helps with wider pieces of molding.
For crown molding, you need to know two main ways to place the molding on the saw bed.
Flat Placement (Coping Method Preparation)
In this method, you lay the molding flat against the saw fence and base. This is common for simple straight cuts or when preparing for coping. It is easy to set up.
Angled Placement (Against the Fence and Base)
This method mimics how the molding sits against the wall and ceiling. You tilt the saw head (bevel) and turn the base (miter). This is key for getting the correct miter saw settings for crown molding.
Deciphering Crown Molding Profiles and Angles
Crown molding is shaped like a small decorative piece that sits where the wall meets the ceiling. Its unique shape means a simple 45-degree cut often won’t work for corners.
The Importance of the Spring Angle
The spring angle crown molding refers to the angle at which the molding leans when installed. Most homes use a 38-degree or 45-degree spring angle. This angle dictates your saw settings.
If you don’t know your spring angle, you can measure it. Or, many modern saws have specific settings listed for common molding sizes. When in doubt, check the manufacturer’s guide for your specific crown molding profile.
Miter and Bevel Basics
To cut a corner, you need two angles:
- Miter Angle: This is the cut made horizontally across the base of the saw table. Think of it as turning the turntable.
- Bevel Angle: This is the tilt of the blade, moving it up or down from the vertical.
For perfect 90-degree inside or outside corners, you usually need a combination of these two angles. These are called comp and bevel crown molding cuts.
Setting Up Your Miter Saw for Inside Corners
Inside corner crown molding cuts are needed where two walls meet inside a room (like a standard 90-degree corner).
The Stall Method (Molding Flat on the Table)
If you place the molding flat, the required miter angle is usually half of the corner angle, or 45 degrees for a 90-degree corner.
- Miter Setting: Set your saw to 45 degrees.
- Bevel Setting: Set your saw to 0 degrees (or the standard bevel for your molding, often 33.85 or 35 degrees, depending on the spring angle).
If you are making an inside corner cut:
- The shortest point of the molding (the inside edge) should be pointing toward the fence.
- The long point (the outside edge) should be pointing toward the blade.
The Upright Method (Molding Against the Fence)
This method is often more accurate for crown molding because it copies the installed position. This requires knowing the spring angle.
For a standard 90-degree inside corner with a typical 38-degree spring angle:
- Miter Setting: Set the saw to 41.5 degrees (This number is derived from 45 degrees minus the bevel needed for the spring angle).
- Bevel Setting: Set the saw to 33.85 degrees (This matches the typical 38-degree spring angle).
To make the cut for the left side of the corner, the molding should lean to the right (if looking from the front). For the right side, it leans left.
Tip: Always test your first cut on scrap wood. This confirms your miter saw settings for crown molding are correct before cutting expensive pieces.
Making Cuts for Outside Corners
Outside corner crown molding cuts occur where two walls jut out from the main structure (like the corner of a bay window). These also total 90 degrees but are cut in reverse.
The Stall Method (Molding Flat on the Table)
Again, this uses 45 degrees on the miter.
- Miter Setting: Set your saw to 45 degrees.
- Bevel Setting: Set your saw to 0 degrees.
The difference here is how you orient the molding for the cut. For the left outside corner piece, the shortest point faces the blade, and the longest point faces the fence.
The Upright Method (Molding Against the Fence)
This mirrors the inside corner setup but reverses the angle direction.
For a standard 90-degree outside corner with a 38-degree spring angle:
- Miter Setting: Set the saw to 41.5 degrees (the same miter as the inside, but used on the opposite side of the blade).
- Bevel Setting: Set the saw to 33.85 degrees.
If you cut the first piece for the left outside corner, the second piece for the right outside corner will use the same settings but will be flipped on the saw table.
| Corner Type | Spring Angle (Example) | Miter Angle Setting (Upright) | Bevel Angle Setting (Upright) |
|---|---|---|---|
| Inside 90° (Left Piece) | 38° | 41.5° | 33.85° |
| Inside 90° (Right Piece) | 38° | 41.5° | 33.85° |
| Outside 90° (Left Piece) | 38° | 41.5° | 33.85° |
| Outside 90° (Right Piece) | 38° | 41.5° | 33.85° |
Note: The key is the orientation of the molding against the fence and base, not just the numbers.
Simplification: Using a Crown Molding Cutting Jig
If calculating compound angles feels too complex, using a crown molding cutting jig simplifies the entire process. This jig is essentially two pieces of wood clamped to your saw table, holding the molding at the exact installed angle (the spring angle).
How the Jig Works
The jig locks the molding into its upright position permanently. When you use the jig, you treat the molding as if it were flat against the wall, even though it is tilted.
- Set the Jig: Clamp the jig securely. Set the bevel angle to match your molding’s spring angle (e.g., 33.85°).
- Cutting: Once the jig is set for a specific spring angle, you only need to adjust the miter angle based on the corner you are cutting. For 90-degree corners, you generally use a 45-degree miter setting on the saw, just like cutting standard baseboard trim.
The jig removes the guesswork from how to miter crown molding accurately. It turns complex compound cuts into simple miter cuts.
Handling 45-Degree and Other Angle Walls
Not every room has perfect 90-degree corners. You must adjust your saw settings for other angles.
Calculating Compound Cuts for Non-Standard Angles
If your inside wall corner is, for example, 80 degrees, you must first find half of that angle: $80° / 2 = 40°$. This 40 degrees is your target angle for the joint.
When using the upright method, you must adjust both the miter and bevel based on the spring angle.
A general rule for finding the Miter setting (M) when using the upright method:
$$M = 45° – (\text{Bevel Angle} / 2)$$
And the Bevel setting (B) is constant based on the spring angle.
- If your corner is 80 degrees, and you want the joint to close perfectly at 80 degrees, you calculate the required adjustment from 45 degrees.
- For the crown molding profile, if you are using the jig, you simply set the saw to the required angle for the joint (e.g., 40 degrees miter for an 80-degree wall).
Cutting Return Cuts
A return cut finishes the end of a piece of molding where it meets a flat wall or doorway trim. This cut angles the end piece back into the face of the molding, making a neat finish.
- Miter: Set the saw to 45 degrees (for a 90-degree wall).
- Bevel: Set the saw to the molding’s spring angle (e.g., 33.85 degrees).
The direction of the cut depends on which way the molding faces the wall. If the molding runs left to right along the wall, the return cut on the right end will be angled one way, and the return cut on the left end will be mirrored.
Practical Steps for Making Crown Molding Cuts
Follow these steps to ensure accuracy and safety when making crown molding installation tips start here.
Safety First
Always wear safety glasses. Unplug the saw when making adjustments to fences or jigs. Keep your hands clear of the blade path.
Marking and Measuring
- Measure Wall to Wall: Measure the length of the wall run where the molding will go.
- Account for Overlap: Crown molding joints require a small amount of overlap for a tight fit. Add about 1/8 inch to your measurement to allow for final fitting.
- Mark the Cut Point: Mark where the inside or outside corner cut needs to begin on the piece.
Executing the Cut
- Confirm Settings: Double-check your miter saw settings for crown molding based on whether it is an inside or outside corner, and if you are using the flat or upright method.
- Position the Molding: Securely hold the molding against the fence and base (or lock it into your jig). Ensure the face of the molding is touching the fence and the back edge is resting on the base plate.
- Make the Cut: Lower the blade slowly. Let the saw reach full speed before cutting. Push the saw through in one smooth motion.
Handling Coping vs. Mitered Inside Corners
While all outside corners must be mitered, inside corners can be mitered or coped.
- Mitered Inside Corners: Both pieces are cut with compound miter angles. This is faster but very sensitive to wall inaccuracies. If the walls are not exactly 90 degrees, the joint will show gaps.
- Coped Inside Corners: One piece is cut square (0-degree miter and bevel), and the second piece is cut with the compound angle, then the edge is shaped with a coping saw to fit perfectly against the profile of the first piece. Coping hides small wall imperfections better.
When coping, you need to make one standard crown molding cut (the first piece) and then use a hand tool to shape the second piece.
Troubleshooting Common Crown Molding Issues
Even with the right settings, problems can arise. Here is how to fix them.
Gaps in Outside Corners
If your outside corner joint has a visible gap:
- Cause: The wall corner is not exactly 90 degrees, or your saw setup is off.
- Fix: If the gap is small (less than 1/16 inch), you can usually fill it with paintable caulk after installation. If the gap is large, re-cut both pieces, slightly adjusting the miter angle by half a degree on each piece in opposite directions.
Gaps in Inside Corners (Mitered)
- Cause: Walls are not square, or the spring angle was wrong.
- Fix: If the gap is on the ceiling edge but tight on the wall edge, your bevel angle is slightly off. If the gap is on the wall edge but tight on the ceiling edge, your miter angle is slightly off. Recutting is the best option, ensuring your setup matches the calculated angles. Alternatively, use the coping method instead.
Molding Rubbing Against the Fence
If the molding is too large for the upright setting or if the blade hits the saw table/fence:
- Fix: You must use the flat placement method (laying the molding down flat) and calculate the angles based on the required miter and bevel for that flat orientation. This works best for smaller crown profiles.
Final Considerations for Installation
Once you master the cutting, successful installation relies on good technique.
- Use Adhesive: Apply a bead of construction adhesive to the back of the molding before fastening. This helps close small gaps and keeps the molding tight against the wall and ceiling.
- Nail Strategically: Nail into the wall studs where possible. When nailing into drywall only, use finish nails driven at an opposing angle (toe-nailing) through the thickest part of the molding profile to maximize holding power.
- Practice Makes Perfect: The first few cuts will be scrap. That is normal. Practice the comp and bevel crown molding cuts on scrap pieces until the joint closes perfectly before cutting your final lengths.
By paying close attention to the spring angle and mastering the upright cutting technique (or using a jig), you can achieve professional-looking crown molding installation tips and results every time.
Frequently Asked Questions (FAQ)
Q: Can I cut crown molding with just a miter saw, not a sliding one?
A: Yes, you can. For smaller profiles (under 5 inches wide), a standard compound miter saw is sufficient if you use the upright method and ensure the molding fits comfortably below the blade guard assembly. For wider molding, a sliding saw is necessary to accommodate the width safely.
Q: What if my wall corners are not 90 degrees?
A: If your wall corner measures 95 degrees, you need the joint to close at 95 degrees. For the upright method, you must calculate the exact miter and bevel required for that 95-degree closure based on your molding’s spring angle. If you use a jig, set the saw miter angle to $95° / 2 = 47.5°$.
Q: How do I know which way the molding leans in an inside corner?
A: When installing, the bottom edge of the molding (the edge against the wall) is always the widest part of the profile, and the top edge (against the ceiling) is the narrowest part. When setting it upright on the saw, this means the molding leans away from you, with the top edge near the blade and the bottom edge resting on the saw base.
Q: Is coping always better than mitering inside corners?
A: Coping is generally preferred by professionals because it tolerates slight imperfections in wall squareness better than a mitered joint. Miters are faster but less forgiving. If your room is brand new and perfectly square, mitering is fine. For older homes, cope the inside corners.