P5 Timber Framing Angle

Timber Framing Angle: P5
P5 = Square Cut Layout Angle on the Jack Rafter. The angle of the square end of the tenon on the long (uphill) side of a jack rafter as seen on the top (roof) surface of the jack rafter. The angle P5 is used with A9 on the hip rafter for the jack rafter mortise.

P5 = arctan (sin D x cos S ÷ cos D)

P5 = arctan (sin D x cos S ÷ cos D)
P5 = arcsin (cos A7 x sin DD)

P5 = arctan (sin(plan angle) x cos(common rafter slope angle) ÷ cos(plan angle))
P5 = arcsin (cos Hip Plumb Backing Angle x sin Plan 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.