I am trying to sort out the often-discussed cutter head issue as it applies to jointers.

I am familiar with straight blades. I also understand the advantages of upgrading to something other than straight. I am just trying to distinguish the differences in the alternatives.

I have seen references to helix, spiral and Byrd. Are helix and sprial synonomous terms? If not, what is the difference? The Byrd is the cutter head with the small four sided cutters, which are rotatable, no?

Now my last question. What are the advantages of each of these to each other? Is the Byrd the "cadillac" of alternative jointer cutter heads, or is it merely an equal to a spiral or helical head?

I thank you in advance for educating me.