Techniques for cutting roof rafters include cutting rafters one at a time, marking rafters all at once and gang cutting rafters. The simplest method is cutting rafters one at a time because it requires fewer tools and less carpentry experience.
To cut roof rafters one at a time, cut a rafter to use as a template. Place the rafters in cutting horses, leaving a gap between each rafter to fit the template fences. Mark the rafters one at a time with the help of the template. Cut the rafters by doing a plumb cut first, then moving to tail cuts and the birds mouth cut.
Marking rafters all at once is a faster technique, but is best used by highly skilled carpenters. To use this method, place rafters in cutting horses. Use triangular blocks secured by screws to push the rafters tightly together and mark the cutting lines all at once. Cut the rafters the same as in the first method.
Gang cutting rafters requires specialized and expensive tools, such as a beam cutter and a worm drive saw. This method is risky, because it cuts all rafters at the same time, and mistakes cannot be undone after cutting. To use this technique, place rafters in a cutting rack and secure them well. Mark the cutting lines and use a worm drive saw and beam cutter to make the top and tail cuts. Finish by using a circular saw to make the birds mouth cuts.