Calculation Results
Bevel Results
Compound Cut Settings
Stair Results
Square Corner Frames
The workhorse cut. Used for picture frames, window casings, door frames, and baseboards meeting at 90°. Set your miter saw to 45° — both pieces get the same cut.
Octagon / 8-Sided
Used for octagonal tables, gazebo frames, or any 8-sided shape. Each piece gets a 22.5° cut on both ends. Interior angle is 135°.
Hexagon Frames
Six-sided projects like hex shelves, planters, or decorative panels. Each of the 6 pieces gets a 30° cut on both ends (360 ÷ 6 ÷ 2 = 30°).
Walls Not 90°?
Measure actual angle with a digital angle finder. Divide by 2 for your miter setting. Most older homes have corners between 88°–94°.
Cope, Don't Miter
For inside baseboard and crown corners — professionals cope rather than miter. Coped joints don't open up as wood expands and contracts seasonally.
Joining Long Runs
When baseboards span longer than one board, join them mid-wall with two 22.5° cuts. Always land over a stud and glue it.
Flat to Wall
Lay crown upside-down on the saw table with bottom edge against fence and back flat. Mimics how it sits on wall — only miter the table, no bevel needed.
Flat on Table
Lay crown flat on saw table and apply both miter AND bevel simultaneously. Needed for large crown or when you can't tilt the saw enough.
Reverse the Cut
Outside corners are the mirror image of inside corners. Flip the workpiece — angles are the same magnitude but applied in reverse direction.
| Spring | Wall Corner | Miter Setting | Bevel Setting | Use Case |
|---|---|---|---|---|
| 38° | 90° | 31.6° | 33.9° | Most common residential |
| 45° | 90° | 35.3° | 30.0° | Larger / ornate profiles |
| 52° | 90° | 38.2° | 25.2° | Flatter, wide crown |
| 38° | 135° | 17.8° | 19.0° | Bay window / 135° corner |
Measure Twice, Cut Once
Before cutting, measure your actual corner angle with a digital angle finder — never assume it's exactly 90°. Most walls are off by 1°–3°.
Always Cut Scrap First
Before cutting good stock, verify your angle on a scrap piece. Hold both pieces together and check with a square. Adjust before touching good wood.
Support Long Pieces
Unsupported long boards flex under their own weight, causing inaccurate cuts and dangerous kickback. Use roller stands at both ends for pieces over 4 feet.
Account for Kerf
Your blade removes material (typically 1/8”). Always cut on the waste side of your line. Sneak up on final dimensions by taking small additional passes.
Back-Cut Crown Molding
After cutting crown angles, back-cut the mating faces at 1°–2°. This ensures the face makes perfect contact with wall and ceiling, hiding minor gaps.
Stair Stringer Layout
Total rise ÷ number of risers = riser height. Total run ÷ treads = tread depth. OSHA: riser 7”–7.75”, tread 10”–11”. Angle = arctan(rise/run).
Glue Strength Tips
Long-grain to long-grain glue joints are stronger than the wood itself. End-grain joints are weak — always reinforce with dowels, biscuits, or pocket screws.
Right Blade for Clean Cuts
Finish work: 80–100 tooth blade. Framing: 24–40 tooth. More teeth = smoother cut, slower feed. Fewer teeth = faster cut, rougher edge.
Allow for Wood Movement
Solid wood expands across the grain with humidity changes. Always allow for movement in tabletops, wide panels, and floor installations.
| Sides | Shape | Corner Angle | Miter Cut Each | Common Use |
|---|---|---|---|---|
| 3 | Triangle | 60° | 30° | Decorative shelves |
| 4 | Square | 90° | 45° | Frames, boxes, baseboards |
| 5 | Pentagon | 108° | 54° | Decorative panels |
| 6 | Hexagon | 120° | 30° | Hex shelves, planters |
| 7 | Heptagon | 128.6° | 25.7° | Specialty decorative |
| 8 | Octagon | 135° | 22.5° | Gazebos, tables, mirrors |
| 10 | Decagon | 144° | 18° | Round-look frames |
| 12 | Dodecagon | 150° | 15° | Clock faces, barrel tops |
| Pitch (X:12) | Angle | % Grade | Notes |
|---|---|---|---|
| 3:12 | 14.0° | 25% | Low slope / shed |
| 4:12 | 18.4° | 33% | Min. for asphalt shingles |
| 5:12 | 22.6° | 42% | Common ranch homes |
| 6:12 | 26.6° | 50% | Very common residential |
| 7:12 | 30.3° | 58% | Standard residential |
| 8:12 | 33.7° | 67% | Steep residential |
| 9:12 | 36.9° | 75% | High pitch |
| 10:12 | 39.8° | 83% | Very steep |
| 12:12 | 45.0° | 100% | Equal rise/run |
| Nominal | Actual (in) | Common Use |
|---|---|---|
| 1×2 | ¾ × 1½ | Furring, strapping |
| 1×4 | ¾ × 3½ | Trim, shelf |
| 1×6 | ¾ × 5½ | Paneling, fascia |
| 1×8 | ¾ × 7¼ | Shelving, fence |
| 2×4 | 1½ × 3½ | Framing studs |
| 2×6 | 1½ × 5½ | Rafters, headers |
| 2×8 | 1½ × 7¼ | Joists, beams |
| 2×10 | 1½ × 9¼ | Floor joists |
| 2×12 | 1½ × 11¼ | Stair stringers |
| 4×4 | 3½ × 3½ | Posts, deck |
| Fastener | Length | Common Use |
|---|---|---|
| 16d Nail | 3½” | Framing, structural |
| 8d Nail | 2½” | Sheathing, subflooring |
| 6d Nail | 2” | Trim, finish |
| 18ga Brad | 1”–2” | Trim attachment |
| #8 Screw | 1¼”–3” | General purpose |
| Pocket Screw | 1”–2½” | Face-frame, joinery |
Ask about miter angles, bevel cuts, compound cuts, crown molding, roof rafters, stair stringers, joinery, wood species, tool tips, and more.
CarpentryBot AI is a premium feature.
Calculators and reference tables are always free.