Jack Rafter Claw Model

This model is an unequal pitched roof, with a 9/12 & 12/12 pitch. This model is a study of the easiest way to draw out the jack rafter claws. The geometry for this model uses the prism plane to develop the jack rafter claw angles. The geometry for the jack rafter claws can be developed using the folding roof surface or the draw down roof surface techniques, but using the prism plane seems to be easier and more accurate than the folding roof surface or the draw down roof surface method.

I really like the 3x4 Chappell gauging square for transferring the layout points from the drawing board to the edge of the rafter material. It’s just the right size.