On occasions, it may be an advantage to lock the relative position of the two rods on the Veritas Dual Marking Gauge, such as when a project requires a constant mortice size, but different offsets.

The shaft clamp lets you lock the relative position of the cutters while still being able to adjust the fence for offset.

This allows you to preserve identical mortice or tenon sizing when joining parts of different thicknesses or when adding a reveal, since it prevents the cutter settings from shifting while the fence is being repositioned.