I’ve received a few questions regarding the way I started doing scarf joints. I adapted my method from watching other builders like Dylan from daemoness and Aaron from blackwater guitars. Basically you rough shape your head piece as a block and glue it on without marching the angle. I did this because when I used to cut the angle, it often times would slip down a bit. Which made things difficult because I had to plane the entire flat surface of the neck down. I don’t have proper tools to do that accurately. So in order to get the job done I had to account for my possible mistakes. So I don’t bother anymore lol. I glue it as is then plane it down using rasps and a hand plane. You can see it in my last walnut build. Worked better than anything I’ve done before.
Make sure you make the rough cut way oversized. It’ll account for any shifts left right front and back. And make sure you make the piece a tad longer so you can glue it with some room. That’s about it. I use binding tape to hold it in place when I clamp because it’s strong as hell.
Hope this helps!