Impact drivers are power tools that may not be that versatile at first glance, but are simply too good at what they are designed for.
If you are working on projects that have you adding and removing a lot of trim screws, framing bolts, and nuts, you will find that an impact driver will quickly become one of the most indispensable tools in your collection.
Especially so if you can match the right size of impact driver to the task at hand – choosing the right impact driver will significantly speed up your work while also doing a lot for your personal comfort.
So what size impact driver do you need? It depends, of course, on what you are trying to do in the first place.
A Note On Corded vs Cordless Impact Drivers...
Before you consider the size of the impact driver you will need, it’s best to start with one of the bigger questions when it comes to these tools.
Do you go for the portability and convenience of a cordless, battery operated impact driver? Or do you choose the reliability, power, and performance of a corded model?
Corded Models: First, let us consider corded impact drivers. If you are just getting your very first impact driver, going for a corded model is never a bad idea. They are cheaper, for one, and you are probably already familiar with all the things you need to pay attention to when using a corded power tool.
Once plugged into the appropriate outlet, a corded impact driver is ready to go all day, without having to take a break to change or recharge batteries.
Many garage professionals prefer corded impact drivers for dealing with larger nuts and bolts, especially if they often deal with ones that are corroded or rusted.
Larger corded impact drivers simply deliver the consistent power and torque that cordless models are yet to match, despite recent advances in cordless brushless impact drivers and lithium-ion battery packs.
For heavy-duty work, a corded impact driver of sufficient size can deliver power comparable to a larger tool, like impact wrenches.
If you want to use your impact driver and an adapter to make use of 1/2 inch impact bits on your 1/4 inch or 3/8 inch tool, you are probably best served by a corded impact driver.
Cordless Models: Then there’s the cordless impact driver, an even more convenient version of a power tool that’s already compact and lightweight. With no cord to get in the way of your work, you can fit a cordless impact driver even inside tight spaces such as engine bays and car interiors.
If you choose one of the compact models, then you have a power tool that’s less than two pounds which can quickly drive out fasteners faster than you can do with a regular drill.
Cordless impact drivers run on battery power, so you will have to get a battery pack and charger to go with your tool.
The initial cost of owning a cordless impact driver is significantly higher than an equivalent corded model, and on top of that, you have to deal with the limited runtime as well.
That said, a cordless impact driver is a lot more handy to have around for outdoor work, as well as any job that will have you climbing up and using your power tools on ladders.
Professionals who do a lot of overhead work, such as steel framing and HVAC installation and repair, will appreciate the convenience of a cordless impact driver.
The same goes for those who work in tight spaces – a compact 12-volt model is hardly noticeable on your tool belt, yet it packs enough torque to drive all but the largest fasteners you need to work with.
Corded impact drivers are rated in terms of amperage, while cordless impact drivers are rated in volts. Generally speaking, a tool with a higher amperage or volts can deliver more power and torque than those with a lower rating.
That said, it’s best to compare the torque itself to give you an idea of the power that the impact driver can deliver.
Torque is usually cited in terms of inch-pounds, or in-lb. A good 18-volt cordless impact driver, for example, can generate up to 1,800 in-lb of torque.
What About An Impact Driver for Automotive Use?
The portability of a cordless impact driver is a huge advantage when it comes to automotive use. When it comes to removing the large number of bolts, lug nuts, trim screws, and other automotive components that you find in most vehicles, efficiency is always appreciated.
The power and reliability of corded impact drivers may have you thinking that these are the best tools for the job.
A power cord, plus the need for an outlet or an extension cord, gets in the way more than it should when it comes to working on vehicles.
A cordless impact driver is simply the more efficient tool for automotive jobs that require you to mover the tool around in tight spaces.
Many automotive pros prefer having two types on hand – a smaller 12 volt (or 18V) compact to get the trim screws and cover bolts out of the way, and a beefier 1/2 inch impact driver or impact wrench to tackle tough lug nuts, corroded bolts, and screws that are stuck.
For automotive use, you might prefer an impact driver with torque control to help you attach fasteners at the recommended torque. You can also use torque sticks to extend and control the torque of your impact driver as well.
Impact Drivers Are Great for Engine Work...
Engine work calls for compact power tools that work well even in tight spaces, and that’s where the stubby impact driver sets itself apart.
A compact 12-volt cordless model can be operated with one hand, and the tool mechanism will prevent torque feedback from knocking the tool out of your hand.
These will give you enough power and torque to zip off 12 mm bolts or nuts, and they can also pull off lug nuts with the right adapter as well, as long as they are not stuck.
Impact drivers with 1/4 inch hex drivers can be used to strip off smaller nuts, trim screws, and bolts. For larger lug nuts, a 1/4 inch square drive impact driver or impact wrench is the better option.
Automotive parts, when installed properly, are torqued to the right tightness. That means a lug nut torques to 1,200 inch pounds can be loosened by an impact driver capable of that torque rating regardless of the size of the nut, unless rust and corrosion are a factor.
Most cordless impact drivers on the market today are capable of 1,800 in-lb or more of torque.
Impact Drivers for Concrete, Brick, and Cement
You can use an impact driver to drill into brick, masonry, and hard stone material, as long as you have the right hex shank drill bits to do the job.
Put one of these hex shank bits into your 1/4 inch impact driver and you can drill through concrete and cement, although it will take you some time.
That said, hammer drills, combi drills, or rotary hammers are still the best tools for drilling holes in concrete or masonry – but you can drill a few holes just fine with an impact driver in a pinch.
Impact drivers are more focused on torque rather than RPM, so using a corded or cordless impact driver will not make that much of a difference when it comes to drilling into concrete.
For best results, pick 1/4 inch bits that are designed for “impact” – that is, they can stand up to the hammering of impact drivers, hammer drills or combi drills.
Impact Driver for Drywall
An impact driver can make for a rather effective drywall screwgun if you have the skill for it. Impact drivers are designed to deliver massive amounts of torque to force screws or fasteners into or out of tough materials.
Drywall, on the other hand, hardly offers any resistance at all to drywall screws, which can make it tricky for you if you want your drywall screws sunk to a preset depth.
Precise control of the impact driver is needed if you want to use it for drywall purposes. A cordless 12 volt model with speed control will let you drive screws at just the right depth, without tearing the paper layer.
They can also drive your drywall screws through tough materials like treated lumber or hardwood, as well.
What About Impact Drivers for Framing?
Impact drivers are incredibly useful for steel framing, where you may have to screw in hundreds of attachments along the course of a project. Granted, the same can be done with a regular drill or power screwdriver.
When time is of the essence, though, the torque supplied by an impact driver will do the job a lot faster, and with less wear and fatigue on the operator as well.
For working overhead with light gauge steel framing, most professionals prefer to use a compact cordless impact driver.
The lack of power cord and the portability of the tool make them a lot more comfortable to use, plus they are safer to bring up on ladders and scaffolding as well.
Impact Drivers for Home Use (General Purpose):
For the typical home uses for an impact driver, many homeowners will appreciate the versatility and convenience of cordless impact drivers.
If the idea of spending a significant amount on a power tool that may not see much use does not appeal to you, then there’s nothing wrong with going for a more affordable corded model instead.
Either type will work as well around the house, and will deliver comparable performance when driving fasteners into wood. Both 1/4 inch or 3/8 inch models are versatile enough for home use, as well.
Deck installation and repairs go by a lot more quickly if you have an impact driver to remove and reattach decking fasteners. The same goes for installing siding, or just about anything that needs a screw removed or re-fastened.
Most homeowners can get by with a 12-volt cordless impact driver, or a corded model of comparable performance.
For those that like to tackle building their own deck or putting up their own siding, they may be better served with one of the more powerful 18-volt cordless models instead.
Using An Impact Driver for Lag Bolts...
Impact drivers will make short work of lag bolts or lag screws, up to an extent. A driver with a 1/4 inch or 3/8 inch bit can be the better choice for smaller screws.
A 1/2 inch impact driver or an impact wrench may actually deliver too much torque that the screws or bolts are quickly stripped, or worse, snapped.
To minimize the chances of stripping or breaking a lag bolt, it’s always a good idea to pre-drill pilot holes into the wood. Not only do the holes make for a good way to ease the burden on your impact driver, they also help prevent the wood from splitting.
Some lag bolts with narrower shafts are actually designed to be driven straight with no need for a pilot hole – for these fasteners, you can simply push them in with an impact driver without pre-drilling.
For very large lag bolts, pre-drilling is a must. In this case, a 1/2 inch impact driver or an impact wrench could be a better choice.
Impact Drivers for General Wood Based Projects:
Impact drivers can drive fasteners into wood, often without the need for pre-drilling pilot holes. While regular drills or power screwdrivers may have difficulty pushing through dense hardwood or treated lumber, an impact driver will happily drive in screws all day long.
A 1/4 inch or 3/8 inch impact driver is plenty for dealing with wood and wood fasteners.
You can also use an impact driver to drill cleaner holes than you can get with a regular drill. The secret is in the spade bit, which can be tricky to use with a regular drill. With an impact driver, there is no risk of kickback should the spade bit meet resistance or binds into the material.
The internal mechanisms of an impact driver divert the torque from the handle of the tool, which makes them unlikely to kick back and injure the operator.
