Cutting sheet metal is not an easy task. The material is hard, the sheet format is quite large. Some types of materials (corrugated sheets or metal tiles) cannot be cut with conventional tools - a grinder or a cutting disc mounted on an electric drill. You need a specialized tool that preserves the polymer protective coating and does not form burrs.
To obtain a clean, straight cut without destroying the finish, roller shears are used. This is a tool that has been known for a long time, but is relatively rare in home workshops, since additional devices are required to pull it along a sheet of metal. Let’s take a closer look at the features and types of roller shears.
What it is
Roller or disk shears are a specialized tool for cutting sheet metal into strips of any length and width. In addition, a curved cut is possible (if the design of the tool and the relief of the sheets allow).
Externally, this is a compact device in the form of double rollers, placed one above the other with a slight axial displacement. The edges of the rollers touch each other, ensuring cutting of the material that falls under the influence of the cutting edges.
Cutting metal (or plastic) occurs when the rollers rotate in different directions. Various forms of drive mechanisms are used, both internal motors and external drive mechanisms.
Most hand-held circular shears are available as attachments for an electric drill or screwdriver.
There are also stationary industrial installations that operate on the same principle. As a rule, they are part of production lines and ensure the execution of certain work operations.
Purpose and areas of use
Disc shears are used for cutting sheet metal. They are used in home workshops for cutting roofing materials, as well as other types of sheet metal or plastic. They are distinguished by high cutting speed without physical effort. The result is a smooth and clean cut without sharp jagged edges or burrs.
Expert opinion
Torsunov Pavel Maksimovich
Most types of roller shears are designed to cut metal with a maximum thickness of 2 mm. However, the work moves most easily if the thickness of the sheet does not exceed 1 mm (for example, roofing material, corrugated sheets or other types of galvanized rolled metal 0.5-0.8 mm thick).
You can cut different types of material:
steel (regular or stainless, annealed)
copper
aluminum
The tool specifications indicate the maximum thickness of the metal being processed relative to carbon steel. The values declared by manufacturers do not always correspond to practical results. For example, when cutting steel of extreme thickness (2 mm), malfunctions are possible. As a rule, they are caused by excessive hardness of the metal.
Roller shears are used in various fields of technology and industry.
Main Applications:
- production and cutting of roofing materials (for example, seam roofing, corrugated sheets, etc.);
- production and installation of air ducts, elements of ventilation systems;
- auto repair shops, service stations;
- production of housings for household and industrial installations, devices, household appliances.
This list is far from complete, but there is no need to present it in its entirety. The use of roller shears is found in almost all areas of technology and industry, in repair and installation work.
Tips for choosing
Before purchasing, the consumer studies the characteristics of the tool:
- power;
- battery capacity (when selecting class models);
- ergonomics;
- maximum metal thickness;
- maneuverability;
- protective functions;
- execution of the starting unit;
- functionality of cutting parts.
The user must remember the safety precautions and check the serviceability of all components of the unit before starting work. When using electric shears, give them breaks to allow the motor to cool down.
The above classification of products for cutting metal blanks will help novice craftsmen navigate the variety of existing models.
Design
Roller shears operate on the principle of a conventional tool, but their cutting elements are modified and have the shape of two rollers.
They are equipped with sharp cutting edges located in the same plane. Along the axis of rotation, the rollers are directed in different directions. When a sheet of metal is placed between the cutting edges, the material is compressed simultaneously from above and below the sheet, separating the parts that are on both sides of the cut line.
There are roller shears with electric drive and with manual rotation. The first designs are preferable because they do not require the application of physical force. This allows the worker to focus on precise mark cutting, or increase productivity when cutting strips.
What muscles does it use?
The exercise has a particular effect on the abdominal and thigh muscles. Most work during its execution:
- abdominal muscles responsible for the abs: rectus, oblique and transverse;
- vastus lateralis;
- rectus femoris muscle;
- adductor magnus and longus muscles;
- hamstring biceps.
Muscles that are most involved when performing the scissors exercise
Advantages and disadvantages
The advantages of roller shears include:
- high efficiency, ease of cutting sheet metal and plastic;
- the tool provides a fast and clean cut without burrs or notches;
- work safety;
- small size, light weight;
- ease of setup and operation;
- can cut steel and non-ferrous metals;
- it is possible to choose the appropriate model.
Disadvantages of roller shears:
- the thickness of the sheets is limited, and as the thickness increases, productivity sharply decreases;
- scissors with one cutting element can only perform straight cuts;
- when performing figured cutting, you cannot make contours with a small radius of curvature;
- if processing is done along the internal contour, you have to make a starting hole for insertion.
Despite some disadvantages, roller shears are highly valued by specialists and home craftsmen. The cleanliness of the cut, ease of operation and precision of work far exceed the quality of alternative tools. At the same time, the worker does not have to exert physical effort, which ensures stable quality and high productivity.
Why you can’t use a grinder for cutting
Fitting sheets of metal tiles is often done using a grinder, despite the strict prohibition of its use for these purposes. Of course, there are quite important arguments in favor of this tool: firstly, the grinder cuts metal very easily, and secondly, the work in this case goes very quickly. But these arguments completely lose their meaning as soon as we talk about the reasons why you can’t cut metal tiles with a grinder.
The documentation supplied with metal tile sheets always contains a clause regarding cutting the material. In this paragraph, among other things, it is always stated that cutting metal tiles with a grinder is strictly prohibited. Of course, this does not stop inexperienced craftsmen, despite the fact that after such cutting the warranty on the purchased material will no longer be valid.
The whole point lies in the special design of metal tile sheets. Upon closer examination, this material turns out to be not just a homogeneous metal, but a multi-layer cake, including a zinc-coated metal sheet, a layer of paint and polymer protection.
If you cut metal tiles with a grinder, the material will heat up excessively, resulting in irreparable damage to each component of the pie. The ones that suffer the most from this are the polymers applied to the material, which are not designed for such high temperatures - they simply melt and subsequently cannot perform their functions. In addition, polymers are damaged not only by direct exposure to an abrasive disc, but even by sparks flying in all directions.
As a result of such cutting, the metal also suffers - the destroyed protective layer exposes the metal layer, which subsequently begins to actively oxidize. Even with a small area of damaged areas, the metal still lends itself to corrosion - and after a couple of years, such a coating will begin to leak, and after a few more years, the material will have to be completely re-coated. In general, you definitely need to think about this before cutting off metal tiles with a grinder.
How to choose the right tool
Choosing roller shears is a task for trained people. It is necessary to take into account your own needs and the specifics of the upcoming work. In addition, it is necessary to analyze the characteristics of models available for sale.
The following factors need to be taken into account:
maximum sheet thickness for this model;
roller diameter;
mobility of knives, type of drive;
number of drive rollers (only the top one or both);
body material.
One of the important points is the possibility and ease of removing the rollers for replacement or sharpening. In addition, you need to pay attention to the method of adjusting the disks and the specifics of setting the gap between them.
The design features of the tool should also be taken into account. There are right and left models (with the top knife positioned on the right or left). They differ only in the location of the cutting elements; all other indicators remain the same.
In addition, sometimes strong rollers are mounted on an unreliable frame, and the strength and power of the support units is insufficient. For an untrained person, it is difficult to determine by eye the degree of reliability of a tool, but any doubts should be interpreted as an important argument against purchasing this model.
The best manufacturers and models
Roller shears are a specific tool used primarily in small-scale production or professional repair work. Therefore, few manufacturers are engaged in the manufacture of such instruments.
Among them are the following companies:
Makita
This is a well-known Japanese concern that produces a huge range of tools and equipment. Makita roller shears are a whole group of items, including hand tools for cutting metal 0.5 mm thick and stationary machines for cutting sheets up to 4 mm thick;
Bosch
A German company known for the quality and durability of its products. Manufactures universal electric scissors capable of cutting various materials (the main purpose is cutting PVC when installing plastic windows);
Machine ToolSupply
A Russian company that produces mechanical and electrically driven disc shears marked SMR;
Van Mark
A company from the USA produces various types of tools and equipment. Roller shears from this company are reliable and easy to use.
Of the most popular models, it should be noted:
Makita CP100DZ
Universal disc shears for cutting polymer materials, linoleum, PVC or thin metal (up to 0.5 mm). Powered by battery, shaft rotation speed - up to 300 rpm;
BOSCH 0.601.9B2.904
Universal electric shears designed for cutting thin sheet materials (mainly polymer). Working shaft rotation speed - up to 700 rpm;
Holzmann-Maschinen RBS15
Mechanical disc shears with manual drive. The tool is designed for cutting sheet metal up to 1.5 mm thick. The feeding of the sheet to the cutting edges is ensured by a lever with a ratcheting mechanism, which simultaneously ensures rotation of the disks;
NS-1600
Self-propelled disc shears, made in the form of an attachment for an electric drill or screwdriver. Capable of cutting sheet metal up to 1 mm (steel) or 1.5 mm (aluminum) thick. They have the ability to adjust the cutting speed in the range from 0.1 to 25 m/min.
This review deliberately did not consider stationary industrial models, since they have a narrow specialization and can only be used to solve production problems.
Exploitation
When producing a large batch of parts, the sheet is mounted on a workbench. Guides for scissors are installed on it or a template is set. The cutting process begins from the edge of the sheet. A hole is made in solid metal into which the lower disk is inserted. By pressing the scissors down and against the template, the device is moved forward by the handle.
Before starting work, the integrity of the cutting edge is checked and a gap is set, depending on the thickness of the material being processed.
Cutting sheet metal with regular scissors is tedious. It is irrational to use a grinder to cut thin sheets. To do this, you should use metal circular knives.
Questions and answers
It is normal for questions to arise at the initial stage of getting to know a new tool. At the same time, different people often have the same questions that should be answered immediately.
Let's consider a few of the most common points that will help remove misunderstandings when choosing or using roller scissors:
What to choose, mechanical or electric? What to choose, mechanical or electric driven tools? driven tools?
The hand tool does not require power supply. This allows you to use it in the field without saving battery power. However, using hand tools requires muscular effort, and the quality of cutting is directly related to the physical condition of the worker. The electric drive eliminates these problems and allows you to focus on cutting accuracy, but requires a power supply.
What size rollers do you prefer?
The larger the diameter of the rollers, the easier and cleaner the metal is cut. Therefore, you should choose a tool with a maximum diameter of cutting edges. This choice will increase the operating time without the need for sharpening, reduce the load on the electric drive, and improve the quality of the cut.
Which is better, a hand tool or a stationary machine?
Manual roller shears are mobile and can be used in the field, on a construction site or at any other site. However, a stationary machine has greater productivity and adjustment accuracy. Therefore, it is impossible to say unequivocally which design option is better. Here they choose based on working conditions and quality requirements.
What is the durability of roller shears?
Most manufacturers make cutting edges from hard tool steel. A resource of 25 km for a straight cut with a metal thickness of 0.5 mm is considered the norm. Based on this indicator, you can approximately calculate the durability of the tool for a certain type of material. At the same time, it is necessary to take into account possible additional loads - a curved cut with a complex configuration, heterogeneity and variety of materials.
If you plan to cut curved parts with small radii, which tools are best to choose?
In this case, the best option would be a tool with small diameter rollers. They turn easier at small radii and are not too resistant to changing the direction of the cut. There are few such devices on sale, so it will not be easy to find a tool for this task.
Independent production of products
Since cutting metal with hand shears is so easy, some craftsmen don't see the point in buying expensive equipment. This is especially true for roller models - expensive and attractive. However, it is not difficult to make homemade metal scissors if the material of the knives is a durable alloy, the strength of which is higher than that of the material being cut.
It is common to use bearings as rollers. Their ends are pre-sharpened. The drive roller is fixed to the handle, with pressure on which the tool is pressed into the workpiece. Next, the user only pulls the sheet of metal towards himself, keeping the handle pressed to the base.
No matter how easy it may seem to make metal scissors with your own hands, it is not recommended. Equipment from well-known brands will ensure safe operation when cutting workpieces and will last longer. In addition, there are models on the shelves that do not require additional units for operation (homemade lever scissors for metal, for example, work only in conjunction with a machine).
