Roof Eave Angle

This is the corner angle of the building. Most Roof Eave Angle corners are at 90°. For Octagons and 45° BayWindows use an Roof Eave Angle of 135°. For Hexagons use an Roof Eave Angle of 120°.
For irregular or bastard hip roofs the Roof Eave Angle can be between 35° and 150° You'll get an Unconstructable error message if the roof is unconstructable with the current input parameters.

Major Roof Pitch

Select the input type from the input menu, Imperial/English Inch base 12 —— default, enter roof pitches from 1—24
like 8 for an 8:12 pitched roof, Metric 300mm base, enter millimeters like 200 for a 33.69007° roof pitch angle,
Decimal Inch base 10 —— enter base 10 decimal numbers like 5.7735 for a 30° roof pitch angle,
Degrees input —— use any roof angle in degrees like 33.69007°

Minor Roof Pitch

Select the input type from the input menu, Imperial/English Inch base 12 —— default, enter roof pitches from 1—24
like 8 for an 8:12 pitched roof, Metric 300mm base, enter millimeters like 200 for a 33.69007° roof pitch angle,
Decimal Inch base 10 —— enter base 10 decimal numbers like 5.7735 for a 30° roof pitch angle,
Degrees input —— use any roof angle in degrees like 33.69007°

The input mode selection can be completely different from the output mode

- Input Menu Mode
- Imperial/English Inch base 12 —— default.. use American standard pitches over 12.
- Metric 300mm base —— 300mm is 11.81102 inches, similar usage to the American framing squares printed in inches.
- Decimal Inch base 10 —— use this option when working with tangents or using the Chappell Master Framing Square multiply the tangent of the angle by 10
- Degrees

The output mode selection can be completely different from the input mode

- Out Menu Mode
- Imperial/English Inch base 12 —— default.. use American standard pitches over 12.
- Metric 300mm base —— 300mm is 11.81102 inches, similar usage to the American framing squares.
- Decimal Inch base 10 —— use this option when working with tangents or using the Chappell Master Framing Square

Purlin Rafter Framing Square Usage

The Miter angle is laid out on the side/face of the Purlin Rafter (set perpendicular to the roof surface plane) and the Bevel angle is laid out on the top of the Purlin Rafter
(in the plane of the roof surface). The Purlin Rafter Saw Blade Bevel Angle produces a compound angle on the Purlin Rafter that results in a bevel angle equal to the jack rafter side cut angle.

SS Angle = Speed Square Angle

Saw Blade Bevel Angle produces compound Speed Square Angle

Purlin Rafter Miter Angle

Mark your purlin rafter with this miter angle on the side/face of the purlin rafter. The side/face is perpendicular to the roof surface plane.

Purlin Rafter Saw Blade Bevel Angle

Set your saw to this angle to produce a compound cut on the purlin rafter.