Timber Framing Angle: P6
P6 = Clip angle on the bottom of the jack rafter for the Hip or Valley rafter housing seat. Jack Rafter Claw Angle following the plane of the top or bottom of
the Hip or Valley rafter.
HawkinDale Formula
- P6 = arctan (tan C5 x cos(90 - P2))
Hip-Valley Roof Ratios Angle Formulas
- P6 = arctan (tan C5 x cos(90 - P2))
- P6 = arctan (tan C5 x sin P2)
- P6 = arctan (tan(Hip Rafter Backing Angle) x cos(90 - Jack Rafter Side Cut Angle))
- P6 = arctan (tan(Hip Rafter Backing Angle) x sin(Jack Rafter Side Cut Angle))
The Hip-Valley Roof Ratios Angle Formulas were developed by Joe Bartok.
The Timber Framing Hawkindale Angle Formulas were developed by Rees Hawkins Acheson from the Martindale Hip and Valley Roof Angles and Hawkindale angle drawings by Ed Levin of the Timber Framers Guild.
The Hawkindale angles were based on the book by Frank L. Martindale "Bevel Angles for Three Dimensional Connections" 1948 that was based on the book
"Hip and Valley Design" by H. L. McKibben and L. E. Gray published in 1912.