Workout what timber you need for the job
This is worth putting some effort into.
I don’t worry too much about over ordering as I it’ll come in for another job. However I don’t want to end up with lots of little bits that don’t have many uses apart from lighting the fire. I’ve got enough kindling as it is.
It takes me a while to figure out on job like my windows where the sections vary in sizes. This is the process I use.
1. Start with the bigger pieces, look to see what stock sizes it can come out of. (Allow enough extra on the pieces to plane flat, square and true. I’d work on at least 2mm per side on 50 x 50mm cross section per meter )
2. Make sure you have the machinery capacity to saw the timber to the rough sizes
3. See what other bits can be cut from the off-cuts, allowing for saw cuts
4. See if by increasing the bought stock you can get more use out of the off cuts
5. Bare in mind, big stock can have internal tension, compounded by a higher uneven moisture content. This means parts cut from it can warp, twist or bow immediately or after further drying out.
6. Work out the most economical lengths. Allow for saw cuts and in/out feed on the planner.
You should end up with an economical cutting list.