I need to make 20 miter cuts for window trim (extension jambs) in
triangular and pentagonal windows with 8:12 slope sides. The stock is 5
inch x 1 inch (true dimension) by anywhere from 48" to 125". The upshot
of this is that I need to make cut 33.7 degree and 56.7 degree cuts
across the 5 inch dimension. My miter saw won't get much past 45
degrees so the 56.7 degree cut is a problem. I'm thinking of building a
jig like the Scarfing jig that Bingham describes on page 100 in
"Practical Yacht Joinery" and using a router but am curious as to
whether there is a more obvious way to skin this cat.
The angles for the window trim which is 4" by 1" (1" nominal depth cuts)
can be cut using my Incra miter sled but I can't make 5" (depth) cuts
with the sled.