Reverse engineering in blacksmithing by Nikos Zantidis

This time, a technical story, about reverse engineering in blacksmithing and use scissors as an example.

Scissors are in essence hand-operated tools. It's worth taking a closer look at how they work and how they're generally constructed. Observing and ‘decoding’.

You distinguish the handles, the pivot point and the blades.

Handles: Come in all shapes and sizes, and are suitable for both left- and right-handed people. And distinctive for all kinds of cutting work.
Pivot: For practical reasons, a screw is preferred. This allows you to easily pull the blades together or loosen them, depending on the cutting task.
Blades: They come in all shapes and sizes. Some are tightly shaped, others are concave to enhance the blade's (flexible) stiffness. Perpendicular to the length direction.The blades are in the lengthwise direction at the cutting plane almost always curved so that they meet at the so-called ‘action point’ during cutting. This action point moves from back to front as the blade cuts.

When repairing or sharpening scissors, it is useful to use the screw on the pivot point to move the blades closer together or looser as needed.
You'll also see scissors that can separate the blades at the pivot point. This is practical for sharpening and cleaning.
When cutting, materials behave differently in relation to each other and the scissors. For example, cutting sewing fabric requires extremely sharp scissors.
Please note that the blades are hardened from 60 Rockwell (HRC) and harder. 60 HRC is a very hard stainless steel with a high carbon content of approximately 1.05. Nevertheless, it doesn't break easily thanks to the addition of elements such as nickel, manganese, and silicon.
There's no formula for blade bending. The arc is determined by trial and error.
All scissors operate on the same principle: slightly curved blades slide past each other, creating shear tension during cutting, which causes the pieces to slide apart, whether it's paper or sheet metal.
There are all kinds of scissors for different purposes. One that stands out is the carpet-making scissors, which have special tips to prevent them from closing. A kind of "stop" is fitted to the tips.
Incorrectly sharpened or blunt blades cause material to be pushed out at the action point.

This evening was an extremely international event.
From beginning to end were 11 very engaged listeners from 10 countries with whom experiences were shared and questions answered.
Nikos can Edward Scissorhands count among its customers!

Announcement:
Today was the penultimate Treff. The organizing team has decided to discontinue the cycle.
The team has worked on this project with great pleasure for five years. We thank everyone who contributed to this project, and of course our listeners, for their input and interesting questions.
The website and YouTube will remain intact as long as the budget allows. At the moment, this is approximately one year from now.

And anyway: The Treff connects !!

The next Treff will be held on November 24th with a presentation by Mariano Garabato on the topic:
Blacksmith Craft alive for the future.

The last Treff is on November 24.
Start: 19.00 CET
Room Open: 18.45 CET