Scissor blades

Factual Questions
1

Why are some scissor blades straight, and some slightly curved?

The cutting edge, I mean. I understand why some are slightly “bent” - this presses the blades together to keep pressure even as the cutting point moves away from the pivot.

Why is the ground cutting edge itself groung into a slight curve? It seems to me that this would tend to “push” the paper or whatever away from the crossing point of the blades and make it much harder to cut things.

I was sharpening the blades on a pair of scissorts, and got to wondering about this. I ground them straight as I’ve also done with my garden shears, and both work fine. I do wonder, though, if I’ve defeated some marvelously thought out little trick from manufacturer.

2

Wow! I had to read that about six times before I realised what you meant…

Have you ever seen a paper guillotine? They also have curved blades. I think it’s to make the blade move at a more oblique angle to the paper, so that only the smallest possible part of the cutting point is in contact with the paper at any one time, to avoid the paper tearing or ‘folding’ into the space between the blades in the most extreme case.

Did that make any sense? It’s a bugger to describe.