Originally Posted by fatboynormmie
The blades that you notched looked like they were notched at a 90 Degree with a sharp inside corner and that could cause issues with a stress fracture from the 90 degree corner to the blade bolt hole.I would round the inside corners of the notch out .Sharp corners create stress risers, couple that with harmonics and it could lead to catastrophic failure.Honestly I would stick with blades that were straight in the center and just stack them right on top of each other ( + )and tighten the bolt down as I never had an issue running them like that in the past. Good luck and be safe.
I understand what you are saying about the stress at the corner, but the flat part of the blades still contact and once they are tightened, I really don't think they would move even without the notches. I have cut some pretty thick growth with this setup (the grass is still really growing in Florida - it was 84 degrees today) and so far have seen no indication of a problem. If I see even the slightest crack I will scrap the whole idea and run them like you said.