US Patent 7121769 Rotary slot milling cutter and cutting insert therefor

A rotary slot milling cutter has a plurality of cutting portions, each cutting portion having an insert pocket and a cutting insert removably mounted therein. The cutting insert includes a top face and a bottom face which has two spaced-apart abutments, with a ceiling formed therebetween. The insert pocket has a generally axially disposed pocket base provided with two support surfaces and a radially extending rib disposed therebetween, the rib having a roof and two banks. When the cutting insert is mounted in the insert pocket, the abutment platforms abut the support surfaces, and a gap exists between the roof of the rib and the ceiling, and between each side-slope and adjacent banks.