What kind of compressor you need for a wrench
Use of the filter
The exhaust air should not contain any impurities. Experienced craftsmen know that condensation accumulates on the internal walls of the receiver when the air is compressed. Also mixing of air and lubricant cannot be ruled out. This can reduce the performance of the equipment.
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To avoid these problems it is advisable to mount a filter on the impact wrench. Its inner part is equipped with a grid made of bronze. The air passes through the filter and is cleaned of impurities. Such a filter has the function of moisture separation.
What are the properties of hoses for pneumatic screwdriver?
For stable and proper operation of the tool, it is necessary to use special hoses, which must necessarily
- withstand pressure of at least 10 atmospheres (if the compressor is designed for this pressure);
- Be oil-resistant, since a few drops of oil are added to the system for good performance;
- The hose cross-section must be large enough to supply the tool with the required amount of air.
The condition of air-supplying hoses must be monitored carefully to prevent them from sharp corners and edges, and exposure to aggressive chemicals. They must be blown out every time before work to prevent dust from entering the wrench. This is the key to the stable operation of the tool.
How to choose the right pneumatic nutrunner
Pneumatic wrenches help you quickly tighten or loosen a large number of nuts and bolts. They are powered by compressed air delivered by a hose from an air compressor. This pneumatic tool is widely used at assembly lines, construction sites, service stations or tire changers, in car repair shops and garages.
Although the purpose of pneumatic wrench is purely professional, today the of this tool are low, so it is available to a wide mass of consumers. But not every automotive hobbyist or craftsman needs one. There are several reasons for this:
1) Use of pneumatic tools is justified in case of large volume of work, when battery-operated or manual tools are ineffective. For example, you’ll have to spend more than an hour under the car if you fasten the front cross member with a regular ratchet. Pneumatic wrench greatly speeds up the work process, saves tedious labor.
2) Cheap 1/4″ and even 3/8″ wrenches don’t always have enough torque to tighten all the nuts and bolts used in cars reliably. Powerful professional models for the average car enthusiast are excessive and expensive.
3) In addition to pneumatic wrenches need another compressor, and it also costs money, but also takes up space in the garage.
Regardless of whether you’re buying a belt or coaxial, oil or oil-free compressor, they all have some common characteristics that you should pay close attention to before you buy:
Power. The higher power of a motor the higher productivity and therefore the more consumers can be connected to a compressor and the more diverse they are. How to choose the capacity? It is better to select it not directly, but according to the required capacity and maximum pressure. These same parameters are selected on the basis of what tools and in what quantity will be used simultaneously with the compressor.
The air tool and the required compressor parameters.
|Tools||Pressure (bar)||Output (lpm)|
|A sandblasting gun||8||250|
The capacity of a compressor is the amount of air it delivers per minute. To determine compressor capacity, add the required capacity of all tools operating at the same time. When selecting a compressor, you must keep in mind that the data sheet usually indicates the volume of suction air in ideal (20 degrees Celsius) conditions. At the compressor outlet, due to air losses in the compressor and varying operating conditions, capacity may be 20-30% lower than stated. Therefore, the working pressure of the compressor chosen should be 30% more than necessary for the work of existing tools.
Pressure. The working pressure of the compressor should also be chosen according to the requirements of the tool to be used. No matter how many tools are to be used at the same time. choose the maximum pressure required. This will be the working pressure of the compressor. Over-pressurization is contraindicated for some tools (i.e. spray guns, blow guns, tire inflators). If such a tool is to be used it would be desirable to have a pressure control. The presence of a pressure gauge will be useful in any case: it allows making sure that the compressor really works and creates the required pressure.
Receiver capacity. A receiver is a metal reservoir that holds a certain amount of compressed air. The larger the receiver volume, the less often the compressor will start, i.e.е. Higher compressed air receiver volumes reduce the compressed air load on the compressor and motor. The downside of a large air reservoir is that it can take some time for the compressor to build up operating pressure. If a compressor is underpowered and has a tool that exerts pressure it can take a very long time to build up pressure in a large receiver and therefore the output of the compressor. Therefore, an increase in receiver volume must be accompanied by a corresponding increase in performance and capacity. An exception is when a compressor is occasionally needed for short periods of high performance, such as with an impact wrench. It requires a capacity of 300 l/m, but if you connect it to a 200 l/m compressor with a large (50 l) air tank it is enough to start the wrench and run it for a while.
How to modify your air compressor to run air tools or impact wrenches
An overheat protection on the compressor is also highly desirable. No piston compressor can run continuously for long periods of time. Availability of an air receiver of adequate volume allows the compressor to periodically “rest” for cooling, but if the air intake is close to the compressor capacity, the intervals between starts are too short and the compressor does not have time to cool down. If the air intake exceeds the compressor capacity, the motor will not shut down at all. This can lead to compressor overheating and failure. That’s why a compressor must always have a capacity reserve.
The weight of the compressor can be quite considerable. up to 100 kilograms! If the compressor is to be installed as a stationary system and connected to a mains supply (e.g. in a garage) then the weight is not so important. But if the compressor is expected to be used in different places, and you need his mobility, you should opt for a lighter model. Or at least have wheels for example.
Compressors are one of the noisiest types of electrical equipment. Even if your compressor will be used in a factory, remember that prolonged human exposure to noise levels in excess of 80 dB is harmful. If you intend to use a compressor near your place of residence, how much more you should think about choosing a model with a lower noise level?
What compressor for the impact wrench to choose
You already have a compressor to which you plan to connect your tools, or you only plan to buy it? In any case, knowing the technical specifications will be useful to you. Why? Let us explain by example.
Surely you have at least once visited forums where craftsmen and hobbyists share their experiences, ask for advice, consult with experts on various technical issues. Here’s an example from life: A buyer has bought several pneumatic tools for a workshop: a grinder, a screwdriver, and a stapler. Connects the first to the compressor works satisfactorily, but for some reason does not give the declared number of revolutions. the electric screwdriver won’t turn on at all! To find out what is the reason, the user begins to look for problems in the compressor. there is a suspicion that it is broken. But the stapler works fine for some reason. So what is the problem?? he asks on the forum. There was a lot of advice and suggestions, he tried everything: he checked the filters, the connections, the oil Finally, it comes to the technical characteristics. Here and it becomes clear that the tools have been picked up without taking them into account. It turns out that the money was spent in vain, and it will be difficult to return the product to the store. After all, it is the customer’s own fault, he refused the advice of salespeople when buying
To prevent this from happening to you and to justify the money you spent, the choice of pneumatic tools should be based on the capabilities of your compressor. So, let’s look at what you need to consider.
Basic selection parameters
If for electric tools one of the important characteristics is power, the devices that work with compressed air, it is not specified. But there are several parameters that are unique to pneumatics.
The air consumption is just the analogue of capacity and characterizes the amount of compressed air consumed per minute. The range on this parameter in different models is from 60 1130 l/min. The higher the value, the more powerful the tool will be. But that doesn’t mean that you should buy the model with the biggest capacity. Otherwise, the compressor can simply not pull too powerful consumer.
The right choice on this parameter is to answer two simple questions:
- What capacity a compressor has?
- How many tools will be connected to it at the same time?
The answer to the first question you will find in the data sheet or instruction manual of the equipment. Let’s say it says 320 l/min. That is, how much air it can deliver.
You will answer the second question yourself, based on the mode in which the pneumatic tool will be used. As a rule, 1 or 2 units are connected to a compressor in a home workshop, because a person works alone and can not perform several operations at once. And on the production from a compressed air source can go ramified pneumatic networks in different parts of the shop to feed equipment for various purposes. There could be more than ten consumers.
Ideally, the performance of the compressor will match the stated parameters at a stable pressure. When it goes down, the amount of air produced also goes down and may not be enough for all the pneumatic tools. Not to cause downtime, you need to secure and have some stock of air. Namely, the productivity of the equipment should be 20 30% higher than the total requirement of all connected devices.
Suppose, for a compressor with a capacity of 320 l / min, you buy a pneumatic spray gun and grinder. If you subtract 20 percent of this value, you get 256 L/min. The combined demand of the two tools must not exceed 256 l/min. That is, for stable operation, the spray gun should consume no more than 125 l / min, and angle grinder 130 l / min (or vice versa).
It is worth noting that for percussion devices, such as staple guns or rivet guns, the air consumption is specified per blow, for example, 1.8 lpd. The need per minute can be calculated by multiplying this figure by the approximate number of blows made during this time.
Another important parameter is the working pressure. This value describes the need for compressed air power to operate a pneumatic tool. This parameter should also be chosen based on the compressor capacity. Suppose, its pressure is 8 bar, then you can connect it to such devices, the operating pressure of which does not exceed 6 bar. Why? Let us explain.
How to choose a pneumatic impact wrench
Before going to the store to buy a pneumatic wrench, you should ask yourself a few important questions, the answers to which will help to make a successful purchase. This tool has many features and applications, so the performance of different models may vary significantly. One particular impact wrench, can be used successfully for one type of work, but is totally unsuitable for another. What you need to consider when choosing:
- Field of application. Decide for yourself in what type of work you are going to use the tool. Whether you need a pneumatic nutrunner for the garage, a compact device for mounting vents or a large unit for unscrewing truck wheels.
- Nut size. The more compact the fastener, the less tightening torque it requires. If you have to drive nuts with thread sizes from M6 to M10, the 1/2″ square drive is the right size. The 3/4″ square nutrunner is the right choice for fasteners with M10 to M18 threads. For large nuts, a 1 in. square is best.
- Torque. Depending on the application, you select the right tool for the job with the right torque, which usually ranges from 300 Nm to 3,000 Nm (excluding the giants of the industry). Car wheels can come off at 300-400 Nm, Kamaz wheels at 800-1000 Nm, and extremely loaded joints can only yield to a tool with a few thousand Nm.
- Tightening control valve. An important factor that adds to your tool’s versatility. Adjustment extends the range of fasteners to be tightened, but has a 10% error on pneumatic wrenches.
- Instrument weight. Prolonged use of heavy and vibrating tools can make life very difficult. If you choose a pneumatic nutrunner for the garage and small domestic work for a few minutes a day, then fit the unit with an all-metal housing. For longer use, lighter tool with composite housing.
Good to know
When you buy a compressor for connecting pneumatic tools, the main task is to choose the exact capacity. The more consumption of pneumatic tools, the more powerful must be the blower. There is another way to solve this problem. increase the volume of the receiver. It is easier and cheaper.
What Size Air Compressor Do You Really Need?
Mid range (3000 to 8000 )
One of the best impact wrenches for the home garage. Powerful enough to handle any bolts and nuts. The heads of the latter do not tear off. There is a case, Rapid coupler and oil sprayer. Complete set with many sockets from 9mm to 27mm. With the right compressor, it can be used for industrial applications. Slightly heavy. weight of almost 3 kg.
Pneumatic impact wrench Eco AIW-600 with external square chuck type. A good choice for any garage or small auto shop. the kit includes a case that is easy to carry. The tool holds a full set of sockets, oiler, union fitting, extension cord. Average torque of 569 Nm, but handles most nuts. Metal housing can even be dropped onto concrete.
Compact Wester PSS-10 impact wrench in the form of a gun with a knurled rubberized handle. Easy to unscrew nuts even in the hardest-to-reach places without fatigue. Has a three-position torque adjustment. Almost no noise and vibrations. All in all, this air wrench is a good solution for a small auto body shop.
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The illustration below gives a detailed look at the impact wrench. The unit consists of the following elements housed in a durable metal case.
- High-performance air motor.
- Impact mechanism.
- Alloy steel chuck (end stop).
- Torque control, and reverse.
- Start button.
- Connector for the compressor hose.
- Air valve.
This unit is much lighter than its electric counterpart due to the lack of a motor. And the torque of the impact wrench is high. from 300 to 2200 Nm (Newtons per meter).
There are 2 main power units inside the machine, each designed to work in different modes. The first unit is the air motor that transmits the rotary motion to the tool head. The second unit is a unit that generates shock loads. Pneumatic actuator rotates due to the passage of compressed air through it, supplied by a high-pressure hose from the compressor.
There are 2 ducts in the body of the device. Each of them guides the air in a different direction relative to the turbine. In the first case, the air pushes the turbine along the h. The first one moves in the direction of the arrow, i.e. in a twisting direction, and the second one. counterclockwise. arrows, on unscrewing the fasteners. Air flows are distributed by a special switch.
The principle of the air screwdriver is as follows.
- After the start button is pressed, the valve is opened and the air flow from the hose connected to the device body starts moving through the turbine, rotating it.
- The turbine sends the rotary motion to the impact mechanism, which in its operating principle resembles a clutch. The mechanism has two cams with a complex configuration. The impact force is created by the cams at the moment when not enough torque is available to release the fastener.
- Further, the rotary movement is transferred to the stop (chuck) with a nozzle for a specified nut size. As a result the fasteners can be screwed or unscrewed. Some air wrenches do not activate the impact mechanism during twisting, the process goes in shockless mode.
- If the nut is hardened, more effort is needed to undo it, at which point the stop rotation stops.
- The hammers begin to deflect backwards, while simultaneously turning.
- In the next stage the jaws bypass the clamping point and continue moving, gaining inertia.
- The knuckles continue to rotate and engage again in the stop and impact (in the direction of rotation).
- The impact pulses continue until the fastener is “ripped off”.
So, with the help of the pneumatic impact tool the process of unscrewing tight bolts and nuts is easy and fast.