Yet another hack :
I hijacked a nice oyster knife I found by chance in a store to make a wood scriber for a right handed woodworker.
I simply reground the stainless steel blade to make it sharp, and single edge, in order to be able to follow a ruler or a square for instance.
Here are the anthropometric pictures :
On the following picture, you can see I left the left side flat.
Notice the little bee, this cheap oyster knife was probably a Chinese forgery of a famous French knife trademark (Laguiole)
Example, with a square, scribing the edges of a tenon on endgrain ...