One of these is not like the other

[le01]

I'm sure many others have noticed this before, but it seems like there is a linear evolution from the straight to the SE to the injector to the carts & disposables. But it seems like the DE is the anomaly. Case in point, straights have a thick blade. So does SE's, and it works in a kind of built in angle in its handle. The injector continues the evolution with the built in angle, but makes the blade smaller and more manueverable. Then the carts/disposables take it to the next level. But the DE is a departure. It has no built in angle. There's the double edge factor.

Just some rambling observations.

 

[xxvaleria]

Actually, DE razors do have a built-in angle--that's why there is a variation in aggressiveness among DE razors. The cap on a DE actually flexes the blade when it is assembled, and a lot of careful engineering and experimentation goes into the design of the head. Regarding the two edges, it is logical to make a symmetrical device if it is not much more expensive than to make an asymmetrical device.