A striking knife is used for marking lines. It combines a knife edge and an awl.
A recent article can be found at http://www.woodcentral.com/articles/STRIKINGKNIFE.pdf
Looking at a picture, I said to myself “there is striking knife inside every spade drill bit”. So I took to one with a grinder. It was fun. Below is the result.
The (right-handed) blade is 9/16’ wide (cut from a 1” wide spade bit), angled at 15 degrees and the bevel is ground at 25 degrees, all as per recommendations. It is sharp enough to pare pine end grain.
The awl scores beautiful lines, and I’m going to use them when I mark out dovetails in future.
Regards from Perth
Derek