Mortise marking gauge with rod clamp
This marking gauge can mark scribes for mortise and tenons and can do so with the scribing bevel on the waste side of the cut. The rod clamp allows you to set the width of the motise chisel then while retaining that setting, align for the position of the mortise and tenon.
several tools don't appear in the photos to the right.
see the tools I use using the Tool Database