I just switched the blades on my Rage 2-blades with the new 40KE blades. I called the manufacturer to make sure that i could do this and they said the 2-blade bodies are the same as the new 40KE bodies. I had 6 old heads from my 2-blades and changed all of the blades out today. On two of the heads, i cannot get the blades to lock in the closed position. It's as if the blades are catching on the o-ring rather than passing over the o-ring into the locked position. I also did change out all of the o-rings and even tried several o-rings on the two heads that i am having problems with. Has anyone else ever experienced this problem?