8 Sided Polygon Rafter Table ( 8 - gon )


central angle = 45
working angle = 22.5
plan angle = 67.5
miter angle = 4.97 & 12 (22.50)
hip run per foot = 12.99
apothem multiplier = 1.08239
side wall multiplier = 0.82843

Pitch

Roof Angles

Frieze Block Angles

Hip Rafters

Jack Rafters

Roof Pitch

Angle

Hip Pitch

Angle

Angle

Saw Bevel

Side Cut

Angle

Backing Angle

Hip Drop

2x

Hip Drop

4x

Length

Per-FT

Side Cut

Angle

First
12 O.C.

First
16 O.C.

First
24 O.C.

Spaced
12 O.C.

Spaced
16 O.C.

Spaced
24 O.C.

Multiplier

0

0.00

0.00

0

22.5

22.50

0.00

0.00

0.00

12.99

22.5

30.63

40.29

59.60

28.97

38.63

57.94

2.41421

1

4.76

4.40

1.97

22.42

22.44

1.82

0.02

0.06

13.03

22.43

30.74

40.43

59.81

29.07

38.76

58.14

2.42258

2

9.46

8.75

3.90

22.18

22.26

3.61

0.05

0.11

13.14

22.22

31.05

40.84

60.42

29.37

39.16

58.74

2.44751

3

14.04

13.01

5.74

21.79

21.98

5.33

0.07

0.17

13.33

21.89

31.57

41.53

61.44

29.86

39.82

59.72

2.48851

4

18.43

17.12

7.46

21.29

21.60

6.95

0.10

0.22

13.59

21.45

32.29

42.47

62.83

30.54

40.72

61.08

2.54480

5

22.62

21.05

9.05

20.69

21.13

8.46

0.12

0.28

13.92

20.92

33.18

43.65

64.57

31.38

41.85

62.77

2.61540

6

26.57

24.79

10.49

20.02

20.61

9.85

0.14

0.33

14.31

20.33

34.25

45.04

66.64

32.39

43.19

64.78

2.69917

7

30.26

28.32

11.79

19.30

20.03

11.12

0.17

0.39

14.75

19.69

35.46

46.64

69.00

33.54

44.72

67.08

2.79494

8

33.69

31.63

12.94

18.57

19.43

12.26

0.19

0.45

15.25

19.02

36.82

48.42

71.63

34.82

46.42

69.64

2.90152

9

36.87

34.72

13.96

17.83

18.80

13.27

0.22

0.50

15.80

18.33

38.29

50.36

74.50

36.21

48.28

72.43

3.01777

10

39.81

37.59

14.85

17.10

18.17

14.18

0.24

0.56

16.39

17.65

39.87

52.44

77.59

37.71

50.28

75.42

3.14260

11

42.51

40.26

15.64

16.39

17.54

14.99

0.26

0.61

17.02

16.98

41.55

54.65

80.86

39.30

52.40

78.60

3.27505

12

45.00

42.73

16.32

15.70

16.92

15.70

0.29

0.67

17.68

16.32

43.32

56.98

84.29

40.97

54.63

81.94

3.41421

13

47.29

45.02

16.93

15.04

16.32

16.33

0.31

0.73

18.38

15.69

45.16

59.40

87.87

42.71

56.95

85.42

3.55932

14

49.40

47.15

17.46

14.42

15.73

16.89

0.33

0.78

19.10

15.09

47.07

61.91

91.58

44.52

59.35

89.03

3.70966

15

51.34

49.11

17.92

13.83

15.17

17.39

0.36

0.84

19.84

14.51

49.04

64.49

95.41

46.38

61.83

92.75

3.86463

16

53.13

50.93

18.33

13.27

14.63

17.83

0.38

0.89

20.61

13.96

51.05

67.15

99.34

48.28

64.38

96.57

4.02369

17

54.78

52.62

18.70

12.75

14.12

18.22

0.41

0.95

21.39

13.43

53.12

69.86

103.35

50.24

66.98

100.47

4.18638

18

56.31

54.19

19.02

12.26

13.62

18.57

0.43

1.00

22.20

12.94

55.22

72.63

107.45

52.23

69.64

104.45

4.35229

19

57.72

55.64

19.30

11.79

13.16

18.88

0.45

1.06

23.02

12.47

57.36

75.45

111.62

54.25

72.34

108.51

4.52106

20

59.04

57.00

19.55

11.36

12.71

19.16

0.48

1.12

23.85

12.03

59.54

78.31

115.85

56.31

75.08

112.62

4.69239

21

60.26

58.26

19.78

10.94

12.29

19.41

0.50

1.17

24.69

11.61

61.74

81.20

120.13

58.39

77.86

116.78

4.86600

22

61.39

59.44

19.98

10.56

11.89

19.63

0.53

1.23

25.55

11.22

63.97

84.14

124.47

60.50

80.67

121.00

5.04167

23

62.45

60.55

20.17

10.20

11.51

19.83

0.55

1.28

26.41

10.85

66.22

87.10

128.85

62.63

83.51

125.26

5.21918

24

63.43

61.58

20.33

9.85

11.15

20.02

0.57

1.34

27.29

10.49

68.50

90.09

133.28

64.78

86.37

129.56

5.39835


Framing Square usage Example: 8:12 Pitch
(Rafter Length Per Ft = 14.42) (Hip Rafter Length Per Ft = 15.25)
SS Angle = Speed Square Angle
Saw Angle produces compound Speed Square Angle
 
Tongue (8.00) Blade (12.00) for Rafter Plumb Cut Angle (SS Angle 33.69)
Tongue (12.00) Blade (8.00) for Rafter Level Cut Angle (SS Angle 56.31)
 
Tongue (8.00) Blade (12.99) for Hip Rafter Plumb Cut Angle (SS Angle 31.63)
Tongue (12.99) Blade (8.00) for Hip Rafter Level Cut Angle (SS Angle 58.37)
 
Tongue (5.38) Blade (15.25) for Hip Side Cut Angle (SS Angle 19.43) (Saw Angle 67.50)
Tongue (3.31) Blade (15.25) for Hip Backing Angle (SS Angle 12.26)
 
Tongue (4.97) Blade (14.42) for Jack Rafter Side Cut Angle (SS Angle 19.02) (Saw Angle 67.50)
 
Tongue (3.31) Blade (14.42) for Purlin Rafter Plumb Cut Angle (SS Angle 12.94) (Saw Angle 12.26)
Tongue (4.97) Blade (14.42) for Purlin Rafter Cross Cut Angle (SS Angle 19.02)
 
Tongue (3.31) Blade (14.42) for Roof Sheathing Plumb Cut Angle (SS Angle 12.94) (Saw Angle 12.26)
Tongue (4.97) Blade (14.42) for Roof Sheathing Cross Cut Angle (SS Angle 19.02)
 
Tongue (8.00) Blade (12.00) for Miter Box Gable Mould Plumb Cut Angle (SS Angle 33.69)
Tongue (8.00) Blade (12.99) for Miter Box 2 Cord Polygon Gable Mould Hip Plumb Cut Angle (SS Angle 31.63)
Tongue (4.97) Blade (12.00) for Miter Box 2 Cord Polygon Gable Mould Hip Cross Cut Angle (SS Angle 22.50) (Saw Angle 22.50)
 
Tongue (3.31) Blade (14.42) for Frieze Block Plumb Cut Angle (SS Angle 12.94)
Tongue (4.97) Blade (14.42) for Frieze Block Cross Cut Angle (SS Angle 19.02) (Saw Angle 18.57)
 
Tongue (3.31) Blade (14.42) for Square Cut Fascia Plumb Cut Angle (SS Angle 12.94)
Tongue (4.97) Blade (14.42) for Square Cut Fascia Cross Cut Angle (SS Angle 19.02) (Saw Angle 18.57)
 
Tongue (0.88) Blade (4.97) for Hip Rafter Square Cut Fascia Plumb Cut Angle (SS Angle 4.18)
Tongue (4.97) Blade (14.42) for Hip Rafter Square Cut Fascia Cross Cut Angle (SS Angle 19.02) (Saw Bevel Angle 18.57)