I'll pretty much second what Ralph said.
I make all of mine out of files. When I finsh forging the striker, I heat it to non-mag and water quench just the striking edge; 1/8" to 1/4" up. But instead of throwing it on the floor, I'll hold it in this position with the tongs until the whole thing cools way past black.
If I'm in the 18th century, I use the grindstone, if I'm at home, I use the bench sander; either way, you have to get the striking edge "in the white" with no scale.
And remember, not all flint is created equal. I use some local stuff that is a knapper's nightmare, but man, it will throw a spark.