06-09-2020, 03:30 PM
Gang cutting goes a long way to making them uniform.
For example a 5/12 pitch roof and a 2x4 wall with 1/2 sheathing on the outside makes the plumb/heel cut of the bird’s mouth about 1.5” at about 22°. A 7 1/4” circular saw can easily handle that.
Line up the boards all on edge. Use the measurements from the rafter calculator to mark the location of the heel cut, scribe the line across all the boards, set your angle and depth of cut, and make the heel cut for all the rafters.
Mark the location for the seat cut, scribe the line. Set the depth of cut to about <1/8” and score your line.
You will need to make the seat cuts separately, but all the measurements and entry cuts are already made.
If you are fortunate enough to have a radial arm saw you can gang about 8-9 rafters and make the seat cut to the cutting depth of the saw, finishing with a jig or hand saw. If you have a ras that can swing a 12” blade like my Dewalt 7790 you can make the entire seat cut.
For example a 5/12 pitch roof and a 2x4 wall with 1/2 sheathing on the outside makes the plumb/heel cut of the bird’s mouth about 1.5” at about 22°. A 7 1/4” circular saw can easily handle that.
Line up the boards all on edge. Use the measurements from the rafter calculator to mark the location of the heel cut, scribe the line across all the boards, set your angle and depth of cut, and make the heel cut for all the rafters.
Mark the location for the seat cut, scribe the line. Set the depth of cut to about <1/8” and score your line.
You will need to make the seat cuts separately, but all the measurements and entry cuts are already made.
If you are fortunate enough to have a radial arm saw you can gang about 8-9 rafters and make the seat cut to the cutting depth of the saw, finishing with a jig or hand saw. If you have a ras that can swing a 12” blade like my Dewalt 7790 you can make the entire seat cut.