Studies of the "Purlin Lip Cut Angle" ... Angle P3
Overview of Juxtaposed Tetrahedra modeling the Angles
Main Slope = 10/12 Adjoining Slope = 7/12
Corner Angle measured between Eaves in Plan View = 90°
Bird's-Eye View of Juxtaposed Tetrahedra
Location Angle P3 (Purlin Lip Cut Angle) on Juxtaposed Tetrahedra
Developments of Tetrahedron modeling Angle P3 (Purlin Lip Cut Angle)
Development of Tetrahedron modeling Angle P3
Formula for Angle P3
Jack Purlin intersects Valley Rafter
Example application of Angle P3
Main Slope = 10/12 Adjoining Slope = 10/12
Corner Angle measured between Eaves in Plan View = 90°
Jack Purlin housed in the Valley Rafter
Jack Purlin housing on side face of Valley Rafter
View of Square Housing Cut and Step Tenon on end of Jack Purlin
Lateral View of Square Housing Cut and Step Tenon
on the Jack Purlin, showing the location of Angle P3
3D Models ... Valley Rafter Peak intersects Principal Purlin
Example application of Angle P3
Main Slope = 10/12 Adjoining Slope = 10/12
Corner Angle measured between Eaves in Plan View = 90°
Intersection of Valley Rafter Peak and Principal Purlin
Tenon at Valley Rafter Peak
Mortise on Principal Purlin to accommodate the Valley Rafter Peak
Valley Rafter Peaks intersect Principal Purlin
Main Slope = 12/12 Adjoining Slope = 10/12
Corner Angle measured between Eaves in Plan View = 90°
Valley Rafter meets intersecting Underpurlins
Note ... intersecting underpurlins are exactly the same as Square Hung Fascia
Main Slope = 7/12 Adjoining Slope = 12/12
Corner Angle measured between Eaves in Plan View = 90°
Underpurlin Miter and Saw Bevel Angles to accommodate Valley Rafter
Underpurlin Miter and Saw Bevel angles to accommodate Valley Rafter
... view of Intersecting Purlins abutting one another
Underpurlin Miter and Saw Bevel Angles to accommodate Valley Rafter
... relationship of Angle P3 to the Miter Angles
Intersecting Underpurlins ... Planes set in the surface of the Roof
Intersecting Underpurlins ... view of the Abutting Faces
Co-Ordinates (Direction Numbers) of Vectors to solve
Saw Blade Bevel = C5a – C5m = Difference of Backing Angles
