I'm looking for replacement blades for black&decker plane mod 21286 or part # 7696,i need set of bldes

Any Internet search will yeild sources. You may find that HSS blades are more $ than carbide ones, IMO because the carbide are old-stock and have not be repriced.

But first make sure you need replacement blades. Initially because the blades are reversable, and 2nd, either the adjusting height control is not functioning OR, and was in my case, the lower plate with 2 screws has slipped inwards. Since I believe the blades slide out after the top plate (3 screws) is removed, do NOT move the lower plates