Simple folding knives with no locking mechanism other than friction were common before the industrial age because blacksmiths were able to make them. A metal ring attached to the blade is a traditional solution, used as early as ancient Rome. In old knives, the axle pin was a rivet, but in this model, it is a screw, allowing for easy friction adjustment. When the friction is adjusted appropriately, the knife can be opened by one hand. The edge of the blade is hardened to super hard and ground extremely sharp, so it cuts wildly like a razor.
Blade: 80CrV2, double-hardened (edge 63 HRC, spine 50 HRC), length 70 mm. Handle: birch plywood, stained black, oiled with boiled linseed oil. Price: 60 EUR.