I bought a few sets of generic woodies that are designed for the rex. The blades are exactly the same thickness all the way along, where as the B400 blades have the plastic bits screwed on at the root to make them thicker. I simply removed this form an old damaged set of blade and sliced off the bits that required an extra hole in the blade for the mounting screw, then just a drop of CA toward the tip end of the spacer when sitting them on the new blades and all is good.