Abstract: A cutting device having concentric counter-rotating cutter rings thereon with the outer ring having end members with support members extending axially therebetween. Cutter packets are detachably mounted on the radially outer side of said support members and are clamped in place by spring biased clamping bars. The housing of the device includes motor operated lift members engageable with said bars singly in respective rotated positions of said outer ring for unclamping said packets for replacement. Each packet has a support plate and a cutter blade adjustably connected thereto.