Metal shears can be divided into two main categories:
In turn, each category has its own subspecies of the tool.
Manual shears for metal are intended forsheet metal cutting: steel with a diameter of 0.5-0.7 mm, roofing iron, metal tile, as well as non-ferrous metals with a diameter of approximately 1.5 mm. Manual scissors consist of 2 short knives and 2 long handles connected by an axle, screw or rivet. When the handles are closed, the knives are closed, which is the working cutting movement of this tool. The length of such scissors is usually from 200 to 400 mm.
Manual scissors are divided into right and left.
Right scissors are designed tocut metal mainly clockwise, and the left, respectively, on the contrary. While cutting, the scissors are held in the right hand, the thumb rests on the upper handle, three fingers clasp the lower part, the index finger or little finger is located between the handles and serves to move them apart.
According to the method of manufacturing scissors are divided into forged, cast and compound-lever.
Forged scissors are high-quality tools and are often quite expensive; they are characterized by increased strength and wear resistance of the cutting edge.
Molded scissors have a less durable material compared to forged and wear much faster.
Composite lever shears create more forceon the cutting edge due to the lever mechanism; for dilution of the lever-grip mechanism the mechanism is provided with a return spring, which makes them more convenient for simple scissors for metal. Knives are made of alloyed cast or forged steel, and the handle levers are made of softer and cheaper.
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Designed for cutting sheet metal to4 mm round rods and squares. Simple lever shears consist of 2 flat knives interconnected by an axis or a screw. The lower blade is fixed motionless to a workbench or workplace, and a handle is attached to the upper movable for ease of working with scissors. The blades often have round and shaped holes of different sizes, they serve to fix the material being cut, as mentioned above, rods, corners, wires.
There are more advanced lever scissors,they have, an adjustable emphasis for exact cutting, the powerful lever. The sharpening angle of the lower knife is 90 °, and the upper knife has a convex curved blade shape and is driven by a lever. The material for cutting is placed on the lower knife, the marking line should be under the upper knife. The right hand pulls the handle on itself, and the sheet of metal is incised. Next, the lever is returned to its original position, and the process is repeated until cutting the workpiece.
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Mechanized (machine) shears for metal
Manual shears for metal by themselvesinefficient, therefore, are used in piece and single production work. In mass and professional works, mechanized shears are used, which are mainly electrically driven.
The most famous of this category are cuttingor scissors for metal. Their principle of operation is based on the vibratory reciprocating motion of the upper knife, which is transmitted from a rapidly rotating eccentric mounted on the motor shaft. The lower knife is fixed on the bracket. Such scissors are designed for cutting sheet steel, metal tiles, profiles with thickness up to 2.7 mm. Their performance is 3-6 m per minute. These scissors are very convenient in work, compact and productive, so they won the love of a large number of professional roofers, tinsmiths and car repairmen. They allow you to easily cut curved figures from sheet materials.
Guillotine shears for metal
Scissors of this type are used on largeproductions, in workshops for cutting sheet metal with a thickness of up to 32 mm, as well as for rolled strip. The principle of operation is the same as that of the lever shears, but unlike them, they have an electric or hydraulic drive of the upper knife, and their dimensions are much larger.
Mostly consist of 2 ostrozatochennyhrollers or circular knives. These knives spin in different directions in the direction from the electric motor through a reduction gear. A sheet of metal as if drawn between them and cut. The rollers are parallel to each other or inclined at an angle of 30-40. ° It is convenient to cut with such scissors strips, round discs and rings, as well as shaped pieces from sheet metal up to 30 mm.