eta:

I have both and even though the multiple bladed one is harder to set up, I find it gives a much better dado. The wobble type only leaves a flat bottom at one particular width. Anything else and it leaves either a concave or convex bottom which you have to clean up with a plough plane. Might as well just do it by hand.

I do like the other one, but I usually just reach for the router. particularly on casework where I am dadoing a large panel.

TEd



TEd