3

I have a pair of scissors which I happen to like a lot. Unfortunately, one of the blades is bent towards the other blade, so that a gap forms when the scissors are closed. Bending the blade back with tongs seems quite difficult since the blade is relatively thick and made out of springy steel which retains its shape.

enter image description here enter image description here

How can I fix these scissors? I have access to an anvil. My idea is to first hammer it flat while its cold, and if that doesnt work, I might heat it below 500°C to soften the steel and hammer it back into shape.


Update

As it turned out, the curvature of the blade and back were not an issue. After I removed the rust and grease residue, the scissors worked flawlessly. Nevertheless I learned a lot from the answers below.

enter image description here

1

First, Watch this youtube video: Scissor Sharpening - with Paul Sellers It's 17 minutes long, but if you keep watching he gives lot's of good information about working on scissors. You really must watch all of it.

Now, I totally agree with MK... the gap is on purpose and forging a no-go. If you really want to do something like that, you should try making some scissors from scratch to get a feel for the process. After that experience, you will probably have a lot more respect for those old shears. That being said, some blades actually are bent too far... and the video above shows how to correct that, too.

Also, I need to address the comment made on MK's answer. Quenching with water makes steel brittle. Water quenching is best left to the absolute, super-duper professional... and even then, I would have my doubts. In this case, you are only dealing with scissors, so (if you were forging them) any old oil should be fine. Vegetable or motor oil would work. You actually don't want scissors to be ultra-hard.

Note: Actually, because of your statement that one blade is bent, I think that you might only have one blade and a "back" (I can't be sure from the pictures). But if that is the case, then typically, only the blade should be bent... not the back (which should remain straight).

enter image description here

enter image description here

Footnote: perhaps I am just seeing an artifact of the photograph, but it looks like you are missing some meat on the ride (or machi☺, see diagrams above). I probalby shouldn't mention it, because it might not be the case, but if you did have that issue then the first thing to know is that adding meat is not realistically possible. You would need to grind/remove steel from the entire inner surfaces of the blades (especially including the metal of the pivot area under the screw) in order to accomodate the worn out ride.

Also, some blades are actually twisted (not bent) counterclockwise (for right handed scissors, vice versa for lefties). Or if you do actually have two blades, then both blades would be twisted counter-clockwise. The twist should be practically imperceptible. Only when the scissors are screwed together would the twist become apparent, as it will hold the blade(s) apart, just like a slight bend would do.

5

It is normal for scissors to have a gap between the blades when they are closed. The blades are bent on a slight curve so that there is a minimal point of contact between the two cutting edges while a closing cutting action is taking place. Without this there would be terrible cutting performance due to tolerance in the surface flatness of the blades and of the ground cutting edges.

Note that you do not want to be heating up the scissor blades to soften the metal enough for trying to hammer on the blades. Doing this will take away the hardness of the blades and basically ruin your scissors. The softened and untempered blades will not hold a decent cutting edge. I suggest that if you try this the scissors will rapidly loose their status as your favorites.

2
  • A slight curve is surely useful in scissors, but the curvature of one of these blades is too large (the scissors dont cut!). I am simply a bit worried to use excessive force while bending them, since I dont want to curve them too much in the wrong direction or possible break them. The steel can be re-hardened by quenching it (in water or oil). – ahemmetter Jul 10 '16 at 11:26
  • Use a knife sharpener on them instead. – Chloe Jul 10 '16 at 17:03

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.