What is the difference between a jackhammer and a hammer drill?
The jackhammer differs from the hammer in its large size and weight, power and increased capabilities. Unlike a hammer drill, a jackhammer is capable of breaking several tons of concrete or other materials per day, and also shows a higher pace of work.
In terms of its size, this model is no larger than a hammer drill, but it has excellent technical characteristics. Weighing only 5.5 kg, the tool is capable of breaking up to 5 tons of concrete daily. The SH-160 demolition hammer handles concrete, brick and stone easily.
It will be convenient for you to work with this model Not only due to its compact size and light weight, but also due to the presence of AVT technology, which significantly reduces vibration levels. The handle of the tool is rubberized and allows you to hold it securely in any working conditions. The SH-160 also has a snap position adjustment function that allows you to change it in a few seconds.
The number of blows when working with the model reaches 3600 per minute, which provides the required pace of work. The bit is held firmly in the SDS-max chuck even during the most intensive use.
In principle, hydraulic hammers are similar to pneumatic ones, only instead of compressed air they use a liquid, most often oil. Accordingly, such a tool requires special expensive equipment that will supply this liquid. This is the least common type of bumpers, which is NOT found in everyday life.
What kind of oil to pour into a jackhammer?
Each manufacturer specifies the brand of oil that is suitable for its jackhammers. When buying a Dnipro-M jackhammer, you will receive gear and shank oil included.
Complete set and attachments
The greater the force of the blow, the more the hammer will be able to beat off in one blow. This indicator is related to the volume of work performed, because the speed of work depends on the strength of the blow. Force is measured in joules and is directly proportional to engine power.
The lightest jackhammers are capable of delivering up to 20 J, in average the impact force is from 20 to 40 J, and the heavy and powerful jackhammers work with a force of 40 J and more.
They have an internal combustion engine that converts gasoline into energy. These hammers are heavier and more powerful than electric ones. They are autonomous as they do not have a power cord. Petrol jackhammers are very convenient to use where there is no way to connect the tool to the network.
Among the disadvantages are the need to refuel the jackhammer and pour oil into it, the presence of exhaust during operation.
Beats per minute
A light and low-power hammer will be able to deliver more blows in a certain time than a heavy and powerful hammer. For example, dimensional models of bumpers hit at a speed of about 1000 beats per minute, and a compact tool can develop a speed of 3500 beats / min and higher. impacts allow for faster destruction of light materials (e.G. Bricks), while high impact forces can destroy even the most durable materials (e.G. Reinforced foundation blocks, floor slabs).
By power, jackhammers can be divided into the following subcategories:
- Here are 900 to 1300 watts. A tool with this power rating can dismantle walls made of brick, stone or concrete.
- Over 1300 watts. Demolition hammers with the highest power are suitable for professional work. demolishing asphalt, concrete, frozen ground, demolishing walls and even foundations.
The weight of a jackhammer depends on its power and capabilities. The lightweight tool will be easy to transport, you will be less tired when working, but it will not be able to complete all tasks. A heavy tool can handle anything, but it takes effort to work.
- Lightweight jackhammers weigh from 6 to 10 kg. They are convenient to use for work at height and inside houses.
- Average weight ranges from 10 to 20 kg. With their help, you can create openings in the walls, destroy partitions, etc.
- Heavy jackhammers (over 20 kg) are not very suitable for household work and are more often used in professional activities, for dismantling monolithic structures, working with large volumes of concrete, granite, etc.
3 best electric jackhammers
- Makita HM1203C. Medium power bump stop. The chuck allows you to set the chisel in 12 positions, adjust the working angle. There are 5 modes of beat frequency, you can choose the appropriate variation in the range of 950-1900 beats / minute. The model is equipped with protection against motor overload, the possibility of a soft start and a stabilization system to maintain the working pace during continuous use.
- Bosch GSH 16-30. The tool of true professionals, daily production. up to 13 tons of material removed. Has a vibration damping system that not only relieves stress from the hands, but also prolongs the life of the bump stop. The body of the device is made of metal parts, durable and not afraid of falls. The tool will remain unharmed even if a wall falls on it.
- Sparky К 615CE HD. This bump stop is equipped with electronics to record the force of the impact under any load. The comfort of work is ensured by an anti-vibration system, smooth start, the ability to independently adjust the force of impact. To protect against overloads there is a LED on the case, it signals overheating and possible malfunctions.
Noteworthy fenders from power supply are also produced by the companies Dnipro-M, Kawasaki, Stanley, Hilti, Zenit.
- Striker. a tool for transferring motion from the engine to the functional part;
- Erysipelas. a working part that performs various work, moving forward and backward at a very high speed, which can reach thousands of beats per minute.
How the fender looks and works?
The impact force here is formed by a special mechanism located under the housing cover. It is he who creates the necessary shock waves, which are transferred to the chisel cutter and further, to the material, destroying it. It all works like an earthquake.
The bump stop is quite heavy, noisy and vibrates very much in the process. True, manufacturers are trying to minimize the effect of vibration, but still, with frequent and intensive use of the hammer, it negatively affects human health.
Concrete breakers are also suitable for home use, but more often they are found on large-scale construction sites or road works. If there is a need to buy such a tool, you need to know how to choose a jackhammer: take an electric or pneumatic one, is the design important, what performance characteristics should you take into account? A competent choice will save you from inconvenience during the work process and greatly facilitate the life of the builder.
Ahead behind the bump stop: nuances, tips
All bumpers are divided into 2 types:
Pneumatic. Most often it is used in complex construction and installation operations, in mines. An outlet is NOT required for work. The bump stop quietly performs its functions in high humidity, and is not afraid of fire and explosions. The tool is intended purely for industrial professional use, not in everyday life. The exception is small hammer drills that act as a bump stop. An example is TOPEX 74L331. A compressor station is needed for smooth operation.
Electric. In such a bumper, vibration is least felt; special skills are not required to use it. Powered by an outlet. Most popular on the market. The segment includes both household models and professional-grade devices. There is also a disadvantage: not suitable for objects with high levels of humidity.
There are also gasoline ones, but they are rarely bought. It is necessary to focus on the power indicator (from an outlet or without it) depending on the category of work performed. So, the electric bump stop is universal, it can crumble concrete in two planes, however, it is worth considering the placement of the motor.
For horizontal tasks, a tool with a vertical motor is needed, and vice versa. Hammers with a horizontal motor are the most compact, weighing up to 10 kg. These household appliances will NOT cope with complex and large-scale construction work. For roads and large construction sites, only a vertical concrete breaker is chosen.
The list of essential parameters required when choosing the best jackhammer (electric or other type) also includes:
How to choose a jackhammer 6 tips
2need a powerful and productive tool to crush walls, floors and even asphalt? There is one called a jackhammer. Neither monolithic concrete, nor frozen impenetrable soils, nor brickwork, nor even the strongest stone can resist it. No obstacles on the way! With such a device, you can in a matter of moments remove old tiles from the wall, make a niche, remove worn out road surfaces and much more.
The thing is useful, but not everyone knows how to choose it correctly and which jackhammer is better. The secrets of a successful purchase are revealed by professionals. And for a “snack”. a rating of 6 top bumpers of different types.
Choosing a pneumatic breaker
Now let’s talk about how to choose a pneumatic jackhammer. For the correct choice of such devices, you need to understand how they work. The pneumatic bump stop consists of the following structural elements:
- Impact mechanism;
- Fixing element;
- Simple spring;
- Shock absorber;
- Adapter spring;
The movement of the nozzle is carried out by moving the concentrated air along special lines. The principle of operation itself is practically no different from models with an electric motor, only such devices are powered differently. Without the presence of some kind of air blower, the device simply cannot work. This is important to consider when choosing equipment. This technique is divided into groups according to the method of air mass distribution:
- Valve models;
- Spools models.
Also, devices are conventionally divided into categories by weight.
Less than 7 kilograms. This is a category of light bumpers, which are used to solve light household tasks.
Up to 10 kilograms. These are medium-weight devices that can be used both at home and on the construction site.
than 10 kilograms. This is a heavy professional equipment that is quite expensive, so it is impractical to buy it for renovation in an apartment.
Such devices must be selected taking into account the following parameters:
- Fender complete set;
- The degree of reliability;
- Ease of use;
- Warranty or service.
This tip is useful if:
- You need to make a hole or equip a niche in the wall structure;
- Cutting of reinforcement is required;
- It is required to dig through the frozen soil;
- Dismantling of metal structures is required.
Demolition hammer: characteristics of choice
- Impact energy;
- The number of beats per unit of time;
- Power supply type.
- Vibration and dust protection;
- Shank type (hex, SDS-max, SDS-Plus,)
- Breaker fixing;
- Chisel fixation in various positions;
- Cable break prevention system;
- Electronic speed control.
The key characteristics in choosing a tool are the number of beats per minute and the value of the maximum impact energy. But in principle, the weight of the instrument can also be operated, because it is directly related to its purpose.
We invite you to rent a power tool or specifically a jackhammer for any period at the most affordable prices.
Basic structural elements for any kind of jackhammers Presented by a striker, nozzle, chuck, etc.
Pneumatic piston models are arranged according to the scheme of piston systems based on the shock principle. The main structural elements are represented by a start valve, a striker, represented by a piston, a fitting for a compressor hose, a cup with a ring valve and a valve box, a muffler. In addition, the jackhammers include two springs, a shock absorber, a retaining ring, a handle, a body.
The named parts are combined into several nodes.
- Impact, also called the launcher and air distribution mechanism, includes a firing pin and a barrel.
- Vibration protection of the handle is represented by a glass and sealing sleeves.
- Anti-vibration chisel protection includes arm and spring-loaded bushing.
- The body-handle includes a body, an aerodynamic silencer and a trigger.
The shock system has two main functions: supply, distribution and removal of air, converting its energy into work.
Electric models Equipped with such specific units as an electric motor, a gearbox that converts the rotation of the shaft of the latter into a reciprocating movement, a crank mechanism with a piston that provides pressure in the cylinder acting on the firing pin.
Components specific for jackhammers with internal combustion engines include the carburetor, fuel tank, starter, ignition system, and fuel pump. In addition, taking into account the increased vibration of these devices, the handle and control elements are separated from the body by a spring suspension.
In addition, there are additional accessories for the hammer. It includes the following four attachments. An automatic speed governor, called soft start and idle speed limiter, serves to prolong engine life by avoiding overloads and gradual acceleration. The principle of its functioning is based on the speed regulation in accordance with the load. The side handle increases ease of use by promoting proper grip and distribution. The impact frequency adjuster enhances tool control by allowing the breaker to be adjusted to suit different hardness materials. The lock of the button ensures that there is no need to constantly hold it during operation.
The principle of operation of jackhammers is to create reciprocating movements of the striker located in the barrel, and not connected kinematically with other parts. This is done by different mechanisms depending on the type of hammer.
So, in piston pneumatic models, the air supplied by the hose from the compressor overcomes the resistance of the valve spring when acting on the handle. As a result, the valve moves, opening the opening of the impact mechanism. Vacuum and excess pressure are created alternately in the lower and upper parts of the cylinder due to the bypass of compressed air between them by the valve system, generating reciprocating movements of the striker.
The operation of the pneumatic turbine hammer is based on the drive of the energy generated by the rotating air of the turbine wheel.
Gasoline hammers are also usually equipped with a pneumatic impact mechanism. The piston, by changing the pressure in the cylinder, causes the piston of the striker to move with the tip attached.
Demolition hammer: purpose, characteristics, use
Demolition work is of great importance in the construction industry. The main hand tool for performing them is a sledgehammer. For large-scale works, an automated mechanism is used, represented by a crane driven Kettle. There is an intermediate version of a mechanized device, suitable for carrying out dismantling works of various sizes. This is a jackhammer.
Several parameters are used to classify the considered devices.
By performance, jackhammers are differentiated into three types.
- Lightweight options are designed for household work. They are capable of crushing plaster, tiles, etc., which makes them suitable for home renovations. The mass of such mini jackhammers is 5-6 kg.
- Medium power devices are suitable for asphalt, therefore they are used for some construction work. Weight from 6 to 10 kg provides long-term horizontal holding.
- In industry and in the construction of buildings, high-power jackhammers weighing 15-30 kg are used.
However, mass is an indirect indicator of performance. There is a classification close to the above, based on other, more significant parameters. It also includes four types.
- The first includes jackhammers with an impact energy of up to 30 J and a frequency of up to 45 Hz. They are suitable for medium-strength materials such as asphalt, brick, clay, and work in confined spaces.
- The second type is represented by options with an impact energy of 40 J and a frequency of 34 Hz, used in general construction works.
- The third type includes models with an impact energy of up to 45 J and a frequency of up to 20 Hz. They are used for vertical impact work with durable materials.
- The fourth type is represented by hammers with an impact energy of more than 50 J and a frequency of up to 24 Hz. Such devices are used for high-strength materials.
Based on the power source, there are four types of jackhammers.
- Pneumatic devices are the most common type. They are powered by a compressor. The principle of operation is based on the pressure of compressed air molecules on the chisel. This equipment is suitable for demolishing any kind of brick and concrete structure. For household options, a power of 5 J is required, and in industrial models this parameter is from 10 to 100 J. This is enough to destroy asphalt, stone, concrete, etc.
- Electric hammers are powered from the mains. The principle of their functioning consists in bringing the striker by means of the rotary element of the electric motor. Performance parameters are up to 1700 W of power, 45 J of impact energy and 2000 beats per minute of frequency. Therefore, these jackhammers have a high impact power but are not suitable for cutting and drilling materials.
- Gasoline devices are driven by an internal combustion engine, which has no valves and no shaft. With low power, the main advantage of these options is autonomy, that is, the ability to use it anywhere. This is due to the absence of the need to connect to an energy source. The duration of operation is determined only by the amount of fuel. In addition, jackhammers of this type are considered safer in comparison with analogues. However, they are distinguished by a high noise level. These models are used in the mining industry, in the destruction of concrete, asphalt, frozen soil.
- Hydraulic hammers use a variety of power sources. They are usually used in rescue operations.
Pneumatic hammers are also divided into two types according to the principle of operation.
- Volumetric devices are driven by rapidly expanding air in the chamber.
- The operation of the turbine variants is provided by the energy generated by the rotation of the turbine.
The simplest classification of jackhammers on the basis of a set of basic parameters differentiates them into professional and household.
Concrete breakers are distinguished by their large dimensions, weight and productivity. These devices are designed for vertical and inclined work with concrete slabs, rocks, asphalt pavements, frozen soils. Rotary hammers are usually more compact than jackhammers or close in size, are more accurate and capable of performing the functions of a drill and screwdriver with speed and reverse control. This versatility makes them much better suited for domestic work. So, the instruction manual for the PE-2520M indicates the possibility of its use as both a jackhammer and a drill.
First of all, it should be noted that jackhammers are mainly professional equipment. This is due to the lack of demand for them for domestic and economic purposes, as well as the high cost.
Consequently, the main factor in choosing a jackhammer is the purpose, that is, the volume and nature of the planned work. This defines the required parameters and functions of the device. In addition, it is impractical to purchase such a device for one-time work.
There are several main parameters of jackhammers.
- Weight determines the ability to keep the device suspended. So, models weighing up to 6 kg are relevant for high-altitude work or cramped conditions. Hammers up to 10 kg can be held horizontally when carrying out horizontal work on dismantling walls and making holes. Heavier hammers can work vertically with foundations, soil, etc.
- The impact force is equivalent to the amount of material chipped off for it. Thus, the efficiency of the tool and the speed of work directly depend on this indicator. It can be from 2.8 to 63 J.
- The impact frequency, reflecting their number per unit of time, also determines the speed of work, but is inversely related to the previous parameter. That is, with an increase in the force of blows, their frequency decreases. So, in light models, this characteristic can be up to 3500, while in heavy models. from 1100.
- Power determines the penetration capacity of the jackhammer and the duration of the working cycle. It is 0.5-2 kW. For finishing works, 1.2 kW is enough. To destroy a concrete or brick wall, 1.6 kW is required. Demolition of the road surface requires the greatest capacity.
The given technical characteristics of jackhammers are largely determined by the type of drive. That is, one of the classifications is of great importance. To understand how to choose a model, you need to know the features of the types allocated to it.
Pneumatic devices, in comparison with electric and ICE hammers, due to their simpler design, are considered more reliable and durable at a significantly lower cost. In addition, they have the smallest weight, ranging from 1.5 to 16 kg. In addition, these hammers are very productive. Finally, these models are suitable for work in conditions of high humidity and near flammable substances. The main disadvantage is the connection to a power source in the form of a compressor, which will have to be purchased separately for a considerable price. over, it is necessary to select this device based on the parameters of the hammer. The main characteristics are volume and working pressure. Compressor parameters determine the duration of operation.
Electric breakers are tied to a power source, just like pneumatic ones. In contrast, such devices should not be used near flammable substances due to engine sparking during operation. They are also not suitable for high humidity conditions. Despite this, they are a very common type of jackhammers. This is primarily due to the significantly higher efficiency in comparison with pneumatic jackhammers and models with internal combustion engines. In addition, they have the best environmental performance, the lowest vibration and noise levels. Despite the external power source, it is not presented as an additional equipment, it provides unlimited operation time and ease of connection. Finally, with a more complex design, they are easy to maintain. In addition to the main parameters, engine power is of great importance for these hammer models. For domestic purposes, jackhammers of this type are most often used.
In addition, there are battery options that combine the above positive qualities of electric hammers with the autonomy of gasoline. Yet they are not mobile for centuries, since the duration of operation is determined by the capacity of the battery, which requires further charging.
ICE models are the most mobile. over, they are characterized by a high level of noise and the presence of toxic emissions. In addition, instead of being tied to an energy source, they require a supply of fuel, the amount of which determines the duration of operation. Finally, jackhammers with internal combustion engines are the most difficult to maintain: they require draining fuel residues, cleaning filters, etc.
In addition, the advantageous working position of the jackhammer is of great importance.
Horizontal modifications are distinguished by their low weight and the presence of appropriate handles: holding the rear and controlling the front.
Vertical breakers are heavier and equipped with side handles.
Finally, the manufacturer is of considerable importance when choosing. There are a number of brands known for their high quality products. The manufacturers producing the best jackhammers include Bosch, Sparky, AEG, Makita, DeWALT, Hitachi, Metabo, Milwaukee.
The main areas of use of jackhammers include construction and mining.
In the first case, they serve to dismantle structures during redevelopment and demolition, cutting metal, removing concrete and asphalt road surfaces, ramming soils in hard-to-reach places, arranging wells, loosening frozen soils, making holes and niches, removing ice.
In the mining industry, jackhammers are used when more powerful equipment is not available. So, the conditions of use in mines, consisting primarily in limited space, determine the need for compact tools. In addition, workings are processed along the entire radius. Consequently, a lightweight hammer is required, which can be used upside down.
The scope of application is largely determined by the type of device: in what conditions and under what atmosphere to work, etc.
Some of the features of the operation of jackhammers were noted above. Regardless of the type of device, general rules are highlighted. First, before starting work, lubricate the tip of the nozzle with any type of plastic grease Litol and grease. Secondly, it is recommended to add grease to the tool barrel when working from two times per shift in order to extend its service life. In this case, various oils are used for a jackhammer in accordance with the annotation. Some recommend I20A, others. gear oil 15W-40, etc. Thirdly, it is necessary to prevent dirt and water from entering the device, rinse the cartridge from lubrication with gasoline after completion of work, having previously removed the nozzle. Fourthly, it is necessary to follow the provisions of the instructions, using the hammer as intended and without overloading. Fifth, once a month it is recommended to carry out maintenance, which includes complete disassembly and flushing of all parts with gasoline or kerosene.
In addition, there are specific features of the operation of each type of jackhammers.
So, a pneumatic hammer after a long break before starting work is recommended to disassemble and rinse in detail with gasoline. Then within two weeks the barrel should be lubricated with pneumatic oil 3-4 times per shift.
For electric models, timely replacement of brushes is required. In addition, technological breaks of 10-15 minutes should be taken at intervals of 25 minutes to avoid overload.
On gasoline jackhammers, it is necessary to preliminarily prepare a fuel mixture, including gasoline and oil of a certain concentration. The instructions indicate which oil to pour into the jackhammer, in what quantity, etc. over, it is required to completely develop the fuel mixture or drain the residues. This avoids contamination of the battery with oil film.
Each type of device under consideration is characterized by specific malfunctions.
The main reason for breakdowns of electric jackhammers is electrical circuit breakdowns, which consist in breaking the button and erasing the brushes transmitting electricity to the motor. Replacing the brushes is easy. Repairing the button is more difficult due to the fact that in many cases it is necessary to disassemble the entire case, however, on modern models, taking into account this feature, it is equipped with a separate cover to simplify replacement.
For models with internal combustion engines, carburetor clogging is typical. Finally, on any jackhammers, there is a jamming of the nozzle in the chuck. In this case, dismantle the cartridge and squeeze out the nozzle, after which the cartridge is washed from lubrication with kerosene.
What is an oil glass cutter and how to work with it. What kind of oil to pour into the glass cutter
An important role in the work of the glass cutter is played by a lubricating fluid. With the correct consistency, it reduces friction and extends the life of the cutting blade tenfold. In addition, the lubricated roller collects glass dust, providing a smoother movement of the glass cutter on the surface to be treated. Let’s see what is the best way to refuel an oil glass cutter.
For a longer service life and comfortable work with the tool, glass cutter manufacturers recommend using special fluids (Bohle, Acecut 5503, Milli M2000, Novacan Cutter Oil and T-3133). These compositions have certain features. They are easily removed from glass with water, do not spread and evaporate quickly. They are usually used in professional cutting, where quality is paramount, and are selected individually, based on the thickness and strength of the material.
Spindle oil or liquid paraffin is often used to cut glass at home. The main thing is that the consistency is liquid and the composition can freely pass through the wick. The most common and proven option is kerosene. You can replace oil for glass cutters with turpentine, white spirit and other ethers. It is not recommended to use sunflower and machine oil, as they have a high viscosity.
How to choose an oil glass cutter
When buying any tool, reliability and efficiency are decisive factors and the oil glass cutter is therefore no exception. The greatest influence on the service life and the quality of operation of this device is exerted by two parameters: the material of the cutting roller and the density of its fixation in the head of the glass cutter. When examining the tool, check that the gap between the roller and the groove is minimal or completely absent. Otherwise, it will cut unevenly.
To sharpen worn-out cutters on Shrovetide glass cutter is an almost impossible task, since they are located on a pin driven into a monolithic head. When a roller fails, the entire tip is replaced or a completely new instrument is purchased. To make your oil glass cutter last as long as possible, choose models with tungsten carbide cutters. Steel alloys in glass processing quickly deteriorate.
Check the sharpening angle with your dealer or on the tool packaging. For household operations, when working with a standard glass thickness from 2 to 12 mm, sharpening at an angle of 130. 140 ° is suitable. Thicker glass, up to 20 mm, can be cut at 150 °. Consider these indicators, and choose a glass cutter Based on the tasks.
It is not worth blindly focusing on the manufacturer’s brand, but you can still pay attention to the models of a particular company. Quite a reliable roller oil glass cutters are produced by the domestic companies ENKOR and Zubr. From foreign ones, the highest quality is worth noting in Krafttool and Stayer, but only in original instruments (fakes are often found). The main thing is to understand that a good tool will not cost cheaply, but a high price will NOT indicate quality. Choose a glass cutter Based on your feelings, based on the information in this manual.
Oil glass cutter device
Most models of oil glass cutters in many ways resemble conventional roller counterparts, but have a more complex design. This tool consists of a reservoir for grease, which also serves as a handle. Below is a metal head with a screw for adjusting the oil supply and a carbide metal (cobalt or tungsten) cutting wheel. The tip is a monolithic element with internal fluid supply holes.
When using an oil glass cutter, lubrication is supplied from the reservoir to the roller, reducing friction and wear on the cutting edge. If you regularly add oil, the tool will be able to cut more than 5000 meters of glass, in contrast to a simple roller, whose safety margin is designed for only 300 meters. Due to the high working life and good cut quality, professional glaziers use a glass cutter with oil, and its ease of use makes it affordable even for beginners.
The average glass thickness that most oil glass cutters can handle is 10mm. There are models designed to work with thick glass, up to 20 mm, and they have a more obtuse roller sharpening angle (150 °). For household use and cutting glass of standard thickness, devices with a sharpening angle of about 135 ° are usually purchased.
How to use an oil glass cutter
When the work surface and the material to be processed are prepared, you can pick up the tool. In fact, to use an oil glass cutter, no instructions are required per se. For successful work, it is enough to know a few simple rules.
Fill the glass cutter tank with liquid NOT to the eyeballs, but about 2/3. For short cuts, you can NOT pour grease into the device at all, but fill a small open container with it and immerse the cutting disc before drawing a line on the glass. In detail about what is poured into the glass cutter, we have already described above.
To cut glass with an oil glass cutter, you need to use a quick, confident movement with a pressure slightly above average. It is better to carefully cut the first 5 millimeters from the upper end of the glass in advance, and then lead the main line. To avoid chipping at the edges of the glass, in the last 5 millimeters, release the pressure. The resulting line of cut should be thin and of uniform depth.
To separate the glass, it is enough to place a small object under the cutting line (a match or a glass cutter handle) and press lightly from opposite sides. If this does not break the glass, you can lift one of its edges and gently tap the glass cutter on it from the opposite side. If even after THESE manipulations the glass does not crack, try making a cut in a different place. It is strongly not recommended to cut the glass cutter several times along the same line. This is the shortest path to blade wear.
If this is your first time with glass cutting, we strongly recommend that you practice in advance on small, unnecessary fragments before moving on to a good material. For a useful visual addition, see How to cut glass with an oil glass cutter.