The Original Blue Book
La página que convirtió la trigonometría en un vistazo. Una fila por pendiente, una columna por corte: cada longitud de cabio común y de lima tesa-limahoya por pie de carrera, lista para multiplicar por tu claro.
Desde 1925
Type your pitch and span. The rafter answers.
6/1226.6°
24ft
Common rafter length
13′ 5″ 1/16″
161.04″ per rafter · 13.42″ per ft of run × 12 ft of run
- Pitch
- 6/12
- Angle
- 26.6°
- Per ft of run
- 13.42″
Schematic geometry. Not to scale, true math, every pitch.
Longitud del cabio por pie de corrida (En pulgadas)
Longitud del cabio por pie de corrida (en pulgadas)
Rows
30
Angle in Deg.
- Rise
- Pitch
- ,
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- 1/12
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- ,
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- 1/6
- Tail Cut loss "A"
- 2¾"
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- ,
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- 1/4
- Tail Cut loss "A"
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- ,
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- 1/3
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- ,
- Tail Cut loss "A"
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- 5/12
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- ,
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- 1/2
- Tail Cut loss "A"
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- ,
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- 7/12
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- ,
- Tail Cut loss "A"
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- 2/3
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- ,
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- 3/4
- Tail Cut loss "A"
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- ,
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- 5/6
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- ,
- Tail Cut loss "A"
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- 11/12
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- ,
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- Full
- Tail Cut loss "A"
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- ,
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- ,
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- ,
- Tail Cut loss "A"
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- ,
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- ,
- Tail Cut loss "A"
- ,
- Common Rafters
- Hip-Val Rafters
Angle in Deg.
- Rise
- Pitch
- ,
- Tail Cut loss "A"
- Common Rafters
- Hip-Val Rafters
A century of the same table.
The rafter length math hasn't changed since Albert Swanson printed it in 1925. The typography modernized, the columns reflowed, the cover got new ink. But the numbers a framer cuts to today are the numbers from the first edition.
| Rise | Pitch | Common rafter (per ft of run) | Hip / Valley (per ft of run) |
|---|---|---|---|
| 1.00″ | 12.04″ | 17.00″ | |
| 6.00″ | 1/4 | 13.42″ | 18.00″ |
| 8.00″ | 1/3 | 14.42″ | 18.76″ |
| 12.00″ | 1/2 | 16.97″ | 20.78″ |
| 16.00″ | 2/3 | 20.00″ | 23.32″ |
| 24.00″ | Full | 26.83″ | 29.39″ |
Same numbers Albert Swanson printed in 1925.
Open the full 1925 TableThe pocket book turned trigonometry into a glance. A framer who can find the number is a framer who never stops cutting.