A groove plane for cutting a groove near the edge of a board, for retaining box or drawer bottoms. 

Designed to use 6mm x 6mm HSS cutter bit.  Cuts a groove ¼" deep ¼" from the edge. 

The main version uses a 1/8" x 1/2" flat bar for the sole, I've included a fully printed version as well for anyone wanting to skip the metal portion.

The flat bar for the sole is two pieces, one 30mm long, the other 120mm long, with a mitre cut on one end. 

A request via the youtube video was for a 3mm version, so I created the model and uploaded it here, but this version is untested.