B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
B27G—ACCESSORY MACHINES OR APPARATUS FOR WORKING WOOD OR SIMILAR MATERIALS; TOOLS FOR WORKING WOOD OR SIMILAR MATERIALS; SAFETY DEVICES FOR WOOD WORKING MACHINES OR TOOLS
B27G13/00—Cutter blocks; Other rotary cutting tools
B27G13/08—Cutter blocks; Other rotary cutting tools in the shape of disc-like members; Wood-milling cutters
B27G13/10—Securing the cutters, e.g. by clamping collars
Tubular spring with bars of varying axial thickness - is formed by cutting axially spaced circumferentially staggered slots normal to axis of metal tube