The lock mitre bit is a great bit for creating panels or 90° corners, as it creates more glue surfaces. A perfect mitre joint can be achieved, with the extra mechanical strength of the joint, and extra glue surfaces. It requires both pieces to be the same thickness, and the use of feather boards is recommended.
Routing 90° corners requires the inside face to be against the table or fence, with the centre of the bit protruding 1/2 way up from the table and from the fence, as seen in the images.
Routing panels requires one panel to be routed face up, and the next to be routed with the face down, to create the matching joint.
This bit will join material from 9.5mm to 18mm.