Viability of using an electric impact driver instead of an air impact wrench

Question

I'm an amateur mechanic, and i'm wondering if i could use an electric impact driver in place of an air driven impact wrench. I don't have a lot of space to use and store an air compressor, so a cordless electric item would be ideal. Plus money is an issue too.

I have a calibrated torque wrench (manual) so I’m not worried about setting the correct torque value with the electric device. Below is an example of an air wrench and an electric driver respectively.

I do various maintenance tasks on my car. e.g. change struts, break discs, exhaust, etc. Maybe i should just stick to manual tools? Please excuse any bad terminology. Thanks.

Answer 1

An impact driver probably will not supply enough torque for what you want to do. The one you pictured is specced to deliver 1330 in-lbs (111 ft-lbs) of torque. I tried using a similar (20V, 1400 in-lbs) Mastercraft (Canadian Tire's house brand) one last year for swapping out winter tires on my car and it wasn't capable of removing the lug nuts without help.

I ended up going with the impact wrench from the same line, which was $260 (compared to the driver's $180 price tag) and is specced for 300 ft-lbs (probably overkill, but there weren't any in between options), which removes things no problem.

Answer 2

I work at a manufacturing plant where we have a need to drive down connections with final torque values of 35 ft-lbs. For ergonomic reasons, we provide our employees with a "run-down" tool for getting the torque close, then they come behind it with a torque wrench (much like what you are doing).

We've found that the electric impact tools have a better life and lower maintenance needs than the pneumatic tools. Mind you, we were using some expensive pneumatic tools that had a clutch setting, in order to ensure we did not exceed 32 ft-lb with the air tool - over torque in our application is a big deal. The clutch tools required oil changes, and if you didn't change the oil, they broke down, and the cost to repair was very expensive.

We replaced these with some panasonic impact electric driver, it too had a clutch setting, and the only issues I've had with it is that the pin which holds the socket has fallen out.

Bottom line: I think the electric impact drivers are an excellent alternative to the pneumatic ones, based on my professional experience.

Answer 3

I'm an amateur mechanic, and i'm wondering if i could use an electric impact driver in place of an air driven impact wrench.

The short answer is yes, the portable electric impact wrench will work great. The Dewalt unit that you show in your picture is the one that I have and it works wonderfully.

I wouldn't worry too much about the battery (other than to get the biggest one you can afford, of course). The thing to remember about the impact wrench is how rarely you're going to use it. It's really only for taking bolts and nuts off. Putting things back together is best left to a more controlled tool so you don't damage threads. If you find yourself buzzing away at a particular fastener for too long, it's probably a good idea to get out the PB Blaster, give the nut a good soak and have a refreshing beverage while you let chemistry help you with you rust problem.

It's also really hard to overstate the delight of a portable when your Mom asks you to cover over and help her undo some rusty bolts. Throw it in the case, drive over, zip zip done, receive accolades. Try that with your air tools.... ;-)

Answer 4

This answer is one of those, Well, it all depends ... answers. All-in-all, I have heard good things about the newer electric impact devices. With improved battery life, they last a long time between charges and can produce reasonable amounts of torque. There are some considerations.

The main thing you need to look at in these tools is what is the amount of torque it can turn. If the maximum amount of torque produced is less than the job at hand, it's not going to work (obviously). All impact tools are going to have a torque rating on them. As that torque value goes up, so does the cost. Air tools have a maximum they can produce, but are also affected by the amount of air pressure and the volume by which the air can flow (what can the compressor sustain).

With the electric impact, you'll need to look at how much voltage the battery pack has, and how long will it last (milli-amp-hour or MAH ... could also be just Ah or amp hour rating). Again, as amp hour ratings go up, so will the price as well as the weight of the tool.

Also ensure you look at the ratings on the piece. Amazon.com customers are pretty good about leaving ratings, but beware of the outlier. Some people, because they have bad experiences with a delivery of a product, will write a scathing review which really has nothing to do with how a product performs (don't just rely on the start rating, but read what is actually said).

Lastly, as you are suggesting, never utilize an impact to tighten a fastener. It is soooo easy to over torque the fastener, it isn't even funny. I will watch tire place mechanics utilize their air impacts to put lug nuts back on, then come back with a torque stick to verify the torque on the nut. When I get home, I loosen them all and retorque correctly. I've utilized a torque wrench to verify the torque is all over the place when they utilize this method.

Answer 5

As an amateur mechanic, I've been using corded/cordless/air impact drivers for almost 20 years. There have been amazing leaps in the technology of cordless drivers in that time. The short answer is that I would highly recommend using modern cordless tools. They are powerful, lightweight, well balanced and have decent battery life.

I also use DeWalt tools but there are many good brands out there. Buy a good name brand product and you won't be sorry. I mostly work on motorcycles. It's a pleasure to use my impact driver to remove engine case bolts, fairing fasteners, frame bolts, ect. They just fly off. Much better to use the tool than get a repetitive strain injury, and it's much faster. You can get through the work quicker.

I have a good set of 1/4", 3/8" and 1/2" impact sockets to use with this tool. I use 1/4", 3/8" and 1/2" adapters for these sockets. The adapters will wear and twist over time; replace them as needed. The 1/2" sockets are pretty big, and most of the bigger bolts need more grunt than the tool provides. Here, I'll use elbow grease or an air tool. Use good quality bits For Phillips screws and replace them before they get worn. When removing a Phillips screw, press hard into the screw to help prevent cam-out.

As the others have said, do not use a cordless drive (or an air impact driver) to start a fastener. It's incredibly easy to cross thread the fastener, plus you have no feel. Also don't use it for final tightening.