re: HELP! Can anyone give me advice on replacing bearings on my planer cutterhead?

It is impossible to cast the bottom around the cutter head, my guess is that the shaft running through the cutter head is removable it should have a long key way . Look for set screws in the cutter head to release the shaft . If no set screws in may be pressed in . Try taking a punch the size of the shaft and tapping the shaft left or right to release the bearing .