How to sharpen metal scissors at home
In the process of long-term operation, sooner or later the question arises of how to sharpen metal scissors. To facilitate the process, it is necessary to disassemble the tool, using both sides of the knife as separate elements. In addition, thanks to this, the procedure will become completely safe.
If the metal scissors only need to be tweaked, then you can use a stone with a grain size of 1000
It is important to choose the right sharpening stone for sharpening scissors. In case the tool needs to be sharpened a little, you can use a thin 1000 grit stone
For sharpening a blunt tool, the edges are pre-processed with a coarser grinding element with a grain size of 100-400, and then with a finer one.
The best grinding material is diamond stone, which has a good effect and will last for a long time. For more accurate results, you can use aluminum oxide or ceramics.
For sharpening a very dull tool, sharpening begins with a sharpening stone with a grain size of 100-400
The first step is to sharpen the inside of the first blade. The sharpening stone must be moistened, then the blade must be placed on its surface. The knife is moved from the point of intersection with the handle to the tip. When sharpening, the entire length of the stone is used without applying too much pressure.
The next step is to sharpen the edges. In this case, the entire surface of the blade should be in contact with the stone. On the entire surface of the sharpening, translational movements are made from the center to the tip of the blade. The sharpening of the other cutting half of the scissors takes place in the same way. At the end, both parts are folded, a couple of cutting movements are performed.
Metal scissors are a versatile tool that is essential for both home and professional use. Thanks to a wide range of product varieties, you can choose the right model that meets the stated requirements.
Design and purpose of units
The parameters and designs with which alligator scissors are manufactured are regulated by the technical requirements of GOST 15032. Typical units of the equipment under consideration are:
- electric motor;
- V-belt transmission;
- flywheel;
- reduction gear transmission;
- inclusion clutch;
- crankshaft;
- balancer with a working tool - knives.
The mechanisms under consideration function in many ways similar to crank / eccentric presses of a slow-speed layout. The movement of the movable knife (in particular, for the N315 shears with a force of 315 tf) is provided as follows. The electric motor transmits torque to the V-belt transmission, which rotates the massive flywheel. Its purpose is to compensate for the fluctuations in the kinetic energy of rotation, which inevitably arise during the forward and reverse cycle of the equipment operation.
Scrap alligator scissors H 313
An engagement clutch is mounted in the flywheel. In older models - for example, for the H313 with a nominal force of 1500 kN - the coupling is made with rigid pivot keys. This limits the permissible torque and reduces the limiting number of starts per minute. But there is no need to connect the H313 to the high-pressure pneumatic network system, and this makes the equipment acceptable for use in open areas, in particular, at the bases for receiving scrap metal.
Hydraulic Alligator Shears
The drive of the equipment with a force of 315 tf is arranged in a similar way.
When the clutch is turned on, the flywheel transfers the rotation to the intermediate shaft, and from it, through the spur gear, to the main, crank, shaft. A lever is attached to the eccentric of the shaft, the opposite end of which is connected to the axis of the swing beam. The second axis of the balancer is fixed to the equipment bed. On the working end of the balancer there is a seat for the working tool - knives, which are made of tool steels of increased hardness and high shear resistance. As such, depending on the type of rolled steel cut, steel U12A, U13, etc. can be used.
Alligator scissors of a mobile design have received some application, for which special carts are used. Not differing in great technological efforts, they are mobile, and, if there is a stationary network with a voltage of 380 V on the basis of scrap metal acceptance, they can quickly move from one place of work to another.
Popular models
Experts identify several models of electric shears that satisfy the maximum number of selection criteria:
Makita JN1601
The Makita JN 1601 nibbler is equipped with a 550 W motor delivering a working frequency of up to 2200 rpm. This is quite enough for high-quality transverse cutting of metal tiles or roofing sheeting.
Advantages:
- The chuck rotates 360 *.
- Cutting depth of steel up to 1.6 mm.
- They cut easily and effortlessly.
Disadvantages:
Leave a slightly rough cut.
Bosch GSC 75-16
Professional sheet metal scissors with a power of 750 watts. Handles steel and aluminum up to 2 mm thick. Ideal for cutting smooth sheets and low-wave profiled sheets. Cut evenly, without burrs and chips.
Advantages:
- Relatively light weight - 1.7 kg.
- Quiet sound of the motor.
- Convenient retainer.
Disadvantages:
- The quality of the cut is highly dependent on the setting of the gap between the cutting edges.
- They don't like rusty steel.
Fein BLK 5.0
Professional nibbler from a German manufacturer. The 1200 W motor allows you to easily cut high-strength steel up to 2.5 mm thick and normal steel up to 5 mm thick. Stroke frequency - 750 rpm.
Advantages:
- Durable die and punch.
- Additional handle included.
- 5 meter cable.
Disadvantages:
- Weight - 3.8 kg.
- High price.
Bosch GSC 12V - 13
The Bosch cordless shears are designed for working with sheet steel (0.6-1.3 mm). Weighing 1.4 kg, they have excellent mobility. The brush motor provides an idle speed of up to 3600 rpm.
Pros:
- Battery overload protection systems.
- System of protection of the device from breakage in case of falling.
- Convenience in work.
Minuses:
They require physical strength and concentration from the operator, with a weak grip they slip out of the hand.
MAKITA DJN161
Makita cordless nibblers allow you to manipulate in hard-to-reach places when installing roofs and façades. The device has an 18 V lithium-ion battery and an electric motor that develops up to 1900 rpm. The maximum cutting depth is 2.5 mm.
Advantages:
- Quiet work.
- Ergonomic handle.
- Compact dimensions.
- Battery charge indicator on the case.
No shortcomings identified.
Makita JN 3200
Cutting scissors. Allows cutting steel up to 3.2 mm thick. The 660 W engine delivers up to 1300 rpm.
Pros:
- Handle-holder, brought out above the main body.
- It is convenient to change the brushes (just unscrew the special nut).
- Perfect straight cut.
- Double insulated power cable.
Minuses:
- It makes a lot of noise when working.
- Are difficult to unfold when making a curly cut.
TITANIUM PPN55-16
The best cheap grade nibbler. Equipped with a 550 W motor that spins up to 2000 rpm. Able to process metal up to 2.5 mm thick.
Pros:
Affordable price.
Minuses:
- Low quality Chinese assembly.
- The torch breaks down quickly at high loads.
Hand-held metal scissors: characteristic features of the tool
Metal scissors are a tool that is designed to evenly cut metal sheets without the formation of iron chips. The cutting process is carried out by means of deformation. When the levers of the tool are exposed to high pressure, due to which the piece of iron is divided into several elements.
Manual shears for metal are made of HSS steel
To obtain a uniform cut, the scissor blades must be at a certain angle and have a small gap. These parameters are selected for the tool based on the sheet material and its strength.
Metal shears can be manual or electric. The first type is used for conventional cutting of steel sheets up to 1 mm thick and aluminum elements (up to 2.5 mm). The device is represented by two cutting bases and two long arms, due to which the necessary pressure is created during the cutting process.
To cut a sheet of metal evenly, the scissor blades must be located at a certain angle.
Electric tools are mainly used for processing corrugated and other sheet metal of complex configuration. This tool is not used for normal cutting.
Manual scissors are mainly equipped with a rigid blade made of HSS steel with a hardness of 65 HRC. There are less durable models that are made from alloy 59 HRC or tool 56 HRC steel, which reduces the price of manual shears for metal. To increase the efficiency of many tool options, each blade is coated with a special substance in the form of titanium nitride, which gives the product additional hardness, making it possible to machine very thick metal sheets.
The metal scissors blade can be smooth or serrated. The first option is used to make a straight cut line, but during the cutting process, the sheet may slip out. The jagged edges prevent the product from falling out. However, this type of blade does not provide a smooth cut.
The scissors jaws can have different profiles. In the first case, when cutting a sheet, a piece of metal will bend back, without interfering with cutting the product further. In the second case, the cut-off metal product is blocked on one of the jaws.
The blades of manual metal scissors can be either smooth or serrated.
Popular models
Hitachi CN16SA
Electric shears for cutting corrugated sheets, which can be useful in professional construction work. The device has a power of 400W and the maximum cutting thickness of carbon steel is 1.6mm. This means that the machine can handle fairly thick material, which expands the range of its capabilities.
This tool allows you to cut in three directions. It is characterized by an ergonomic shape of the body, thanks to which the scissors can be operated with only one hand. In this case, the cut line is perfectly visible because the sheet metal filings are thrown down. This also eliminates the risk of eye contact.
Makita JN1601
Makita JN1601 is the ideal tool for cutting regular and corrugated metal sheets. With this tool, you can quickly check the material thickness thanks to the measuring grooves.
The model has a power of 550 W and a compact size. The ergonomic shape of the device was made possible by the use of a modern motor, which affects the efficiency of the device. When working, the hands do not get tired too quickly, which makes it comfortable to use.
Stanley 2-14- 563
A simple model made of chrome-molybdenum steel. This material is extremely strong and durable, which can positively affect the service life of the presented scissors. For added comfort, the spring has been reinforced and chrome-plated mounts have been added.The handle of the product is ergonomic, so the hand holding it does not get very tired.
The scissors are equipped with a hardened serrated blade. This prevents them from sliding off the metal, so the sheet can be cut much faster and easier. The product is also ideal for cutting plastic, aluminum, copper and other materials. In addition, the product looks very aesthetically pleasing.
Irwin 10504313N
Shears Irwin 10504313N are used for cutting sheet metal with a maximum thickness of 1.52 mm. With them, you can also successfully cut stainless steel with a maximum thickness of 1.19mm. The product has a serrated bottom blade that allows for a smooth and precise cut.
The model has profiled soft handles. The manufacturer also took care of increasing the cutting length, which translates into a better distribution of the power used.
The advantage is that this equipment can only be operated with one hand. And this increases the level of safety (there is no risk of accidental injury to the other hand).
Bosch GSC 75-16 0601500500
The 750 W electric model is equipped with a very efficient motor. The device allows you to achieve maximum speed with little effort.
The model weighs only 1.8 kg, so it is not that difficult to hold it in your hand. When working, the cutting line is clearly visible, which ensures high accuracy of work. The four-sided knife of this tool can be easily replaced, which keeps the equipment productive for a long time.
One of the main advantages of these scissors is their ease of use.
Irwin 10504311
Scissors for cutting metal (250 mm, straight). Made from quality material. Serrated blades provide precise and even cuts. The anatomically shaped two-piece finger grip prevents the hand from slipping. This reduces the load during long-term operation.
Features of hydraulic products
The products are designed for cutting metal structures (rods, shaped iron, scrap, reinforcement) by means of a uniformly distributed force along the length of the blade. They are conventionally divided into two groups:
- small-sized;
- oversized.
Hydraulic shears are actively used by rescue services
The former are also called tame. For example, the following are manual hydraulic shears NGR-20 "KBT". Their purpose is to cut armored cables, fittings, steel ropes. The main characteristics are:
- permissible thickness of the cut product - 20 mm;
- cutting blade of increased strength (60-62 on the Rockwell scale);
- maximum effort - 5 tons;
- length - 36 cm, weight - 3.2 kg;
- the presence of a rotating guillotine head;
- addition of the design with a lever for pressure relief;
- cost about 20 thousand rubles.
Large tools are bolted to the base machine. Intended for:
- scrap metal cutting;
- recycling of cars, buses, trucks;
- dismantling of metal structures;
- cutting and recycling of rolling stock;
- cutting boats, ships, boats.
The impressive metal shears are available in several series. For example, models of the AD class dismantle steel structures, MP-T is suitable for slitting metal (sheet), DS for reinforced concrete, and so on.
Disc shears, also known as roller shears, are more advanced in design. The working bodies are roller knives, which, when rotating in different directions, are pressed into the workpiece and cut it. Mutual friction between metal and discs causes the sheet to move along the tool.
Roller shears for metal
Usually circular shears have two rollers - at the top and at the bottom. Their mutual arrangement is of three types:
- parallel;
- with one inclined roller;
- with both tilting rollers.
Manual circular shears with a parallel position of the working bodies are used for cutting metal into strips.The second group is used when working with circular or round workpieces. The third is for them, but with a small radius.
By the principle of operation, they resemble ordinary household counterparts. A static knife is attached to a rigid support, a movable knife is attached to a perpendicular plane. The support zone is adjustable, so that the user selects the desired gap between both blades for the thickness of the workpiece.
Sheet metal shears cut the workpiece only from the edge; from the middle the design will not allow. Curly cutting is also difficult to carry out.
The demand for products is due to the competent ratio of the thickness of the cut sheet and the cost. For example, Makita BJS160Z sheet metal scissors cost about 10 thousand rubles, while they have the following characteristics:
- maximum cutting thickness for steel - 1.6 mm, aluminum - 2.5 mm;
- the minimum cutting diameter is 0.5 m;
- battery power;
- frequency of strokes - 4300 / min.
This tool is sufficient for standard household and garage work.
Since cutting metal with handheld scissors is easy, some craftsmen don't see the point in buying expensive equipment. This is especially true for roller models - expensive and attractive. However, making homemade metal shears is not difficult if the material of the knives is a strong alloy, the strength of which is higher than that of the material being cut.
The use of bearings as rollers is common. Their ends are pre-sharpened. The drive roller is fixed to the handle, with pressure on which the tool is pressed into the workpiece. Further, the user only pulls the sheet of metal towards himself, keeping the handle pressed against the base.
No matter how easy it may seem to make scissors for metal with your own hands, this is not recommended. The equipment of well-known brands will ensure safe work when cutting workpieces, and will last longer. In addition, there are models on the shelves that do not require additional units for work (lever scissors for metal are homemade, for example, they only work in conjunction with the machine).
Specifications
Technical indicators:
- maximum thickness of the cut sheet;
- diameter of discs;
- processed grades of metals and steels;
- curly or flat cutting;
- type, mobility of knives;
- type of drive;
- right, left.
In the passport, the thickness of the cut sheet is indicated by carbon steels. Aluminum, copper sheet is softer. Their permissible thickness exceeds iron-based alloys by 30-50%.
The possibility of curly cutting, the minimum radius of the line is indicated in the passport.
According to the relative position of the knives relative to the marking line, mainly right-hand knives are released. The left ones are in little demand, they differ only in the mirror arrangement of all parts.
For machines with an electric drive, the performance or cutting speed is indicated.
Exploitation
Before starting cutting, the following requirements must be observed:
- fix a sheet of metal in the clamping mechanism, or press it against the work table to avoid beating;
- it is forbidden to carry out the cutting operation without personal protective equipment.
For a high-quality cut line without defects, it is recommended to do the following:
- you should firmly hold the scissors in your hands at right angles to the surface, preventing skewing, otherwise steps and scuffs will turn out on the workpiece;
- when processing in the center of the sheet, you must first make a hole with a drill;
- to reduce the processing time, the cutting line should be lubricated with ordinary machine oil, and also additionally applied to the working tool.
To increase the lifespan of the electric scissors, it is recommended:
- timely replace the working tool in order to prevent premature wear of the gearbox and engine;
- cool down the power tool drive;
- it is forbidden to cut surfaces in the presence of water and dirt on them;
- after finishing the treatment, blow out the ventilation ducts and remove dust and dirt.
To prevent injury, it is recommended that you comply with the following requirements:
- check the health of the parts of the electric scissors;
- it is forbidden to carry out processing if there is damage on the supply cable;
- protective goggles and gloves should be worn;
- it is forbidden to touch the cutting line with unprotected hands;
- do not touch the gearbox during operation.
Compliance with the requirements of safe operation, as well as recommendations for cutting, will help the operator to process metal parts with high accuracy, without defects along the cutting line.