SBE Builders

Strong Built Establishments Builders

SBE Builders is a commercial and residential framing contractor located in Discovery Bay California. Dedicated to the art of Carpentery & Roof Framing. We are the professionals for the future of the craft of carpentry.

Development of Rake Crown Molding Miter Angles
Using geometry

24 Sided Polygon Crown Molding Angles

Crown Molding Tools
crownmoldingtools.com

Crown Molding Tools  

Upside down and backwards in a miter box or compound miter saw has been used for the last 200+ years by the majority of carpenters to cut crown molding miter and bevel angles. Right sideup and backwards for rake crown molding cuts were developed long before our time, but even today there's still confusion about the correct crown miter and bevel angles when cutting rake crown molding laying flat in the miter box or compound miter saw. By using plane geometry for developing rake crown molding profiles you can determine the correct miter and bevel angles for rake crown molding.

24 Sided Polygon Crown Molding Angles

24 Sided Polygon Crown Molding Angles

24 Sided Polygon Crown Molding Angles

Trigonometric Relationships between Tetrahedron Angles by Joe Bartok
Joe Bartok's Trigonometric Relationships between Tetrahedron Angles web page is the most significant treatise on roof framing angles in the last 100 years. If your a roof framer print out Joe's Trigonometric Relationships between Tetrahedron Angles web page and study the trigonometric relationships between each of the triangles. If your an interior trim carpenter, then just use the crown angle formulas below.

Trigonometric Crown Angle Formulas for Horizontal Plane Crown Molding Angles
Crown Miter Angle = arctan (sin( Spring Angle) tan ( Wall Corner Angle 2 ))
Crown Miter Angle = arctan (sin( 38) tan( 45)) = 31.62
 
Crown Bevel Angle = arcsin (cos( Spring Angle ) * cos( Wall Corner Angle 2 ))
Crown Bevel Angle = arcsin (cos( 38) * cos( 45)) = 33.86

or you can think of the wall angle as the miter bisect angle
Crown Miter Angle = arctan (sin( Spring Angle) tan ( Wall Miter Bisect Angle ))
Crown Miter Angle = arctan (sin( 38) tan( 45)) = 31.62
 
Crown Bevel Angle = arcsin (cos( Spring Angle ) * cos( Wall Miter Bisect Angle))
Crown Bevel Angle = arcsin (cos( 38) * cos( 45)) = 33.86

or you use the crown slope angle instead of the crown spring angle for horizontal plane crown molding angles
Crown Miter Angle = arctan (cos(Crown Slope Angle) * tan( Wall Miter Bisect Angle ))
Crown Miter Angle = arctan (cos( 52) * tan( 45)) = 31.62
 
Crown Bevel Angle = arcsin (sin( Crown Slope Angle ) * sin( Wall Miter Bisect Angle))
Crown Bevel Angle = arcsin (sin( 52 ) * sin( 45)) = 33.86

Trigonometric Crown Angle Formulas for Vertical Plane Crown Molding Angles (cathedral/vaulted ceilings/rake gables)
Crown Miter Angle = arctan (cos( Spring Angle) tan((180 - (Roof Pitch Angle * 2)) 2 ))
Crown Miter Angle = arctan (cos( 38) tan((180 - (33.69 * 2)) 2)) = 27.71
Crown Miter Angle = arctan (cos( 38) tan(56.31) = 27.71
 
Crown Bevel Angle = arcsin (sin( Spring Angle ) * cos((180 - (Roof Pitch Angle * 2)) 2))
Crown Bevel Angle = arcsin (sin( 38) * cos( 56.31)) = 19.97


 
Development of Tetrahedron Geometry
based on Joe Bartok's Tetrahedron Developmental Geometry
Development of Tetrahedron Geometry
Development of Tetrahedron for Crown Molding Geometry Using Spring Angle and Wall Angle
Development of Tetrahedron for Crown Molding Geometry Using Slope Angle and Corner Plane Angle
Development of Tetrahedron for Crown Rake Molding Geometry
Crown Moulding Miter Angle and Bevel Angle Settings Calculators

Crown Spring Angle = 52
Crown Spring Angle = 45
Crown Spring Angle = 38
Wall Angle Settings
Rake Crown Spring Angle = 38
Rake to Horizontal Crown Spring Angle = 38
Polygon 2 Cord Exterior Rake Gable Crown Molding Miter Angle and Bevel Angle Settings
Polygon 2 Cord Interior Rake Gable Crown Molding Miter Angle and Bevel Angle Settings
Polygon Crown Molding Angles Development & Calculator

Octagon Roof Exterior Crown Molding Angles Development Calculators
Octagon Roof Interior Crown Molding Angles Development Calculators
Corner A Crown Molding Calculator
Corner B Crown Molding Calculator
Corner C Crown Molding Calculator
Corner D Crown Molding Calculator

Crown Spring Angles

Crown Spring Angle
Polygon Crown Molding Miter Angles and Bevel Angles

12 Sided Polygon Crown Molding

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SBE Builders
SBE Builders
5305 Laguna Ct.
Discovery Bay, California 94505
(925) 634-6022 • Fax: (925) 634-6022
Commercial & Residential Framing Contractor
Build it Green Framing Contractor
American Carpenter and Builder
California Licensed General Building Contractor
CA LIC.#  546126
Expert Witness for Construction Structural defects


Roof Framing Geometry

  • Roof framing geometry is empirical-type knowledge.
  • Information gained by means of observation, experience, or experiment.
  • From ground Line 0: Z1, Z2, Z3 etc...
  • To Roof Axis 0: A1, A2, A3 etc...
  • To the bring back line 0 for scribing: B1, B2, B3 etc...

Roof Framing Geometry Blog

Rafter Tools for Android
With Quad Tetrahedra Analytic Algorithm Technology.
Helping apprentice carpenters on their journey to becoming master carpenters with Certification in roof framing.

Rafter Tools+ for iPhone

Rafter Tools+ is a rafter calculator for complex roof framing angles that other roof framing calculators don't offer.

RafterTools+

Crown Molding Tools
crownmoldingtools.com

Crown Molding Tools  

Carpenters Of Steel

Canadian & American Geometric Roof Framing Development
using a Steel Framing Square

Geometric Roof Framing Development for Irregular Hip Roof Calculations
using a Steel Framing Square

Geometric Development of Tetrahedron
using a Steel Framing Square

Hip Rafter Backing Bevel Angles from 1565 to 2013

Applied Geometry and Euclidean GeometryA lesson in Applied Geometry and Euclidean Geometry

This Is Carpentry

We're a member of the Timber Framers Guild

Timber Framers Guild

American College of the Building Arts, carpentry and timber framing programs.

American College of the Building Arts

Would you like to have the knowledge and abilities to build a real Master Piece"
Patrick Moore is currently offering courses on 'L'Art du Trait'.

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