I just finished filing out my first hand made wood screw and learned a big lesson. You can file the threads on in the wrong direction.
I went to thread the screw in my nicely drilled pilot hole and the dang thing would not tighten up until I was going to unscrew it, then it tightened right up.
I thought you guys might get a laugh out of that.
Oh, come on now, don't tell me I'm the only one who has done this