The old threshold in this interior doorway was well worn and cracked with age.I removed it and got a new piece of red oak from the lumber store.
I traced the old shape onto the new board.
I cut these out with a jigsaw, arching in for the first cut, then cut out that whole piece, then cut into the next tier.
On the other side I did it a little different, making a wider slice that gave me enough room to move the blade around.
I used a rasp to clean up my cuts, bringing them to the pencil lines, and rounded the bottom edge of the ends so that I could drop it into the doorway for a test fit.
I set the saw to the angle of the old threshold, which was 65 degrees. Please be advised that this is a very dangerous cut to make, because you basically have to reach around the spinning blade. (Please also leave a comment if you can think of a safer way I could have done it.)
Feed the board into the teeth of the blade. This allows the blade to push the piece against the backstop and keeps it under control.
Do NOT feed the board from behind the blade, even though this is the direction the saw would usually cut. At this angle, it pushes the piece away from the backstop and can throw it off the path, which binds up the blade and marks up your board. (Yeah, I learned this one the hard way.)
Beltsand off the saw burns (and the teeth marks as best as you can) and round the edges.
You can also use the beltsander to round the bottom edges of the ends so it will fit in place.
It's still a little snug for my taste, but close.
I used the rasp to take down a few problem spots on the ends, then gave the whole thing a once-over with a sanding sponge.
I nailed it in place with 6 nails, using a center punch to set the nails in a bit without the risk of leaving a mark from the hammer.
All done. Now to repaint the molding (which I probably should have sanded before I nailed the threshold down).