This large 4" spoilboard surfacing bit is designed for use with router sled setups, & suitable for cnc machines.
 On this bit, you will never need to get your cutting edges professionally sharpened, thanks to the 4 sided replaceable inserts. Simply loosen the screw, rotate 1/4 turn, & retighten screw for a brand new, razor sharp cutting edge.
 The bit comes with 1 set of inserts already installed.