Cordless Impact Wrench

A Cordless Impact Wrench  is a socket wrench power tool designed to deliver high torque output with minimal exertion by the user, by storing energy in a rotating mass, then delivering it suddenly to the output shaft.

Compressed air is the most common power source, although electric or hydraulic power is also used, with cordless electric devices becoming increasingly popular in recent times.

Cordless impact wrenches are widely used in many industries, such as automotive repair, heavy equipment maintenance, product assembly (often called “pulse tools” and designed for precise torque output), major construction projects, and any other instance where a high torque output is needed.

Cordless impact wrench is amongst the practical inventions in the 21st century in the industry of home appliances that assist in offering a high torque in a rock or wall with the use of compressed air or electricity. This wrench, also known as air wrench or torque gun is actually a powerful instrument which produces high torque with minimum energy getting for its consumer. And once putting it like that, you’ve got no other option but to like this tool.

Cordless impact wrenches are available in every standard socket wrench drive size, from small 1/4″ drive tools for small assembly and disassembly, up to 3.5″ and larger square drives for major construction. Cordless impact wrenches are one of the most commonly used air tools, and are found in virtually every mechanic’s shop.

Cordless impact wrenches are available in all sizes and in several styles, depending on the application. 1/4″ drive wrenches are commonly available in both inline (the user holds the tool like a screwdriver, with the output on the end) and pistol grip (the user holds a handle which is at right angles to the output) forms, and less commonly in an angle drive, which is similar to an inline tool but with a set of bevel gears to rotate the output 90 degrees. 3/8″ impacts are most commonly available in pistol grip form and a special inline form known as a “butterfly” wrench, which has a large, flat throttle paddle on the side of the tool which may be tilted to one side or the other to control the direction of rotation, rather than using a separate reversing control, and shaped to allow access into tight areas. Regular inline and angle 3/8″ drive impact wrenches are uncommon, but available. 1/2″ drive units are virtually only available in pistol grip form, with any inline type being virtually impossible to obtain, due to the increased torque transmitted back to the user and the greater weight of the tool requiring the larger handle. 3/4″ drive impact wrenches are again essentially only available in pistol grip form. 1″ drive tools are available in both pistol grip and “D handle” inline, where the back of the tool has an enclosed handle for the user to hold. Both forms often also incorporate a side handle, allowing both hands to hold the tool at once. 1.25″ and larger wrenches are usually available in “T handle” form, with two large handles on either side of the tool body, allowing for maximum torque to be applied to the user, and giving the best control of the tool. Very large impact wrenches (up to several hundred thousand foot-pounds of torque) usually incorporate eyelets in their design, allowing them to be suspended from a crane, lift, or other device, since their weight is often more than a person can move. A recent design combines an cordless impact wrench and an air ratchet, often called a “reactionless air ratchet” by the manufacturers, incorporating an impact assembly before the ratchet assembly. Such a design allows very high output torques with minimal effort on the operator, and prevents the common injury of slamming one’s knuckles into some part of the equipment when the fastener tightens down and the torque suddenly increases. Specialty designs are available for certain applications, such as removing crankshaft pullies without removing the radiator in a vehicle.

In operation, a rotating mass (the hammer) is accelerated by the motor, storing energy, then suddenly connected to the output shaft (the anvil), creating a high-torque impact. The hammer mechanism is designed such that after delivering the impact, the hammer is again allowed to spin freely, and does not stay locked. With this design, the only reaction force applied to the body of the tool is the motor accelerating the hammer, and thus the operator feels very little torque, even though a very high peak torque is delivered to the socket. This is similar to a conventional hammer, where the user applies a small, constant force to swing the hammer, which generates a very large impulse when the hammer strikes an object. Energy is stored over time, allowing a very strong, but short output impulse to be generated from a relatively weak, but constant input force. The hammer design requires a certain minimum torque before the hammer is allowed to spin separately from the anvil, causing the tool to stop hammering and instead smoothly drive the fastener if only low torque is needed, rapidly installing/removing the fastener.

These tools ought to be used with caution as well as safety. One needs to understand his/her needs and understand the appliances well before utilizing them for regular or critical jobs. The usual troubles confronted by amateurs and newbies are cross threading and to over-torque the actual bolts than required. Therefore if you are new at using an impact wrench, it would be recommended to hand-tight the screws immediately after making use of this wrench.

– Battery Size –
For cordless impact wrench, power is determined by battery voltage: the higher the voltage, the more power and torque the impact wrench has available. While more power and torque may seem like like something you want, there are trade-offs to be made. With high voltage cordless impact wrench, along with the additional power, comes additional cost and additional impact wrench weight.

Here is a typical comparison to illustrate the point. A typical 9.6 Volt cordless impact wrenchwill typically weigh in the neighborhood of 3-1/2 pounds and cost anywhere from $35 – $150. As a comparison, a 19.2 Volt cordless impact wrench can weigh up to 10 pounds and cost in the range of $125 – $300. If the increased torque and power of a 19.2 Volt cordless impact wrench is really needed, the added cost may be worth it. But if you are using your cordless impact wrench to occasionally drive screws in your home, a 19.2 Volt cordless impact wrench is probably not worth it since it is harder to use (since it is heavy) and money not well spent. If you really do not need the additional power, a cheaper, light-weight cordless impact wrench will probably suit your needs much better.

– Number of Batteries –
Another point to consider when buying a new cordless wrench is the number of batteries that come included with the tool. If you plan on using your wrench for extended periods of time or often, you will want to only consider impact wrench that come with two batteries. It is very frustrating when your batteries dies in the middle of something and you have to wait a couple of hours for the battery to charge before you can get back to what you were doing. When you are purchasing a cordless impact wrench, make sure it comes with two batteries. If it does not, look up the cost of an additional battery and include that when you are comparing costs between impact wrenches.

– Battery Type –
Two types of batteries are for sale for cordless impact wrenches: Lithium Ion (Li-Ion) and Nickel Metal Hydride (NiMH). Do yourself a favor, do not purchase a cordless impact wrench that uses NiMH batteries. Yes, it may be cheaper, but it is cheap for a very good reason. NiMH batteries have issues with memory problems (they need to be completely discharged before they are recharged or they lose charge capacity), they do not last for as many charge cycles (the batteries die quicker), and they are lower power than equivalent voltage Li-Ion batteries.

– Battery and Tool Storage –
Even when your cordless impact wrench is off, it will draw a small amount of energy from the battery. While the amount of energy being drawn is slight, it can add up to a significant amount over the course of days, or weeks. So when you put away your cordless impact wrench, be sure to remove the battery; this will help ensure that the battery is charged when you need it. Do not keep your battery in the charger for extended periods of time. While there are some chargers that claim to be “smart” about this, but as a rule storing your cordless impact wrench batteries in the charger will lead to them dying sooner than if you do not. When storing your batteries avoid storing them in heat and cold. Cold weather will not harm your battery long-term, but it will decrease the amount of available power when the wrench is being used. High heat can permanently ruin the batteries of your cordless impact wrench. Avoid high heat, and do not charge your batteries in an area that is overly hot, this can permanently damage the battery.

–Charging Your Batteries–
Many higher-end cordless impact wrench now come with advanced chargers that allow the battery to be charged in a very short period of time; often in about 15 minutes. For comparison, a standard charger can take up to 3 hours to charge the battery. If you need a quick-charging battery for your wrench, look into the charging options that are available prior to getting a cordless impact wrench.

– Pick a Brand –
An easy way to avoid problems with battery availability is to decide on a battery size and brand and stay with it. If you consistently purchase the same brand of impact wrench with the same battery size when buying drills, trim saws, reciprocating saws, screwdrivers, etc, you will be able to share batteries and chargers between all of your tools. This will increase the number of available batteries and it ensures that you will never run out of charged batteries.