Here is a marking gage that is critical to some measurements at the bench. You will notice the block is diffeent for the 2 gages. One tool is for a "lefty" and the other is for the right hander.
This design is from Steve Latta's design from FWW magazine.
I have some pieces from a class I taught at Phil Soper's house years ago.
Marking Gage and Workshop
Take a look at the photo album to see the parts and steps to build one of these tools.
Dan