The Groove Mill operation cuts O-Ring Grooves that lie on a face of a part. This includes grooves that have undercuts produced with a dovetail cutter. The Groove Mill operation dialog contains only settings for groove milling. You set just a few items, such as the Groove Width and Groove Depth.

You can cut the groove with one pass. Or if the groove width is larger than the tool, you can turn Finish Walls on. After the center line rough pass, the operation inserts a radius transition move to the first wall, then another radius transition move to the second wall. Set Plunge Type to Ramp to maintain a high quality floor finish. 

To automatically create an entry hole for dovetail cutting, turn on Mill Hole for Dovetail Cutter. The Geometry is The setting lets you use any wireframe edge from a solid model to create the cut. Or you may use the top or bottom centerline.