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cordless half inch impact wrench

Cordless Power Tools: Can They Replace Pneumatic Tools?

by Larry Carley copyright 2015

I recently attended Milwaukee Tool's annual media tool preview event where they unveiled over 80 new products that will be available later this year and early next year. Milwaukee Tool is known primarily as a leading supplier of professional grade power tools for the building trades (carpenters, plumbers, electricians, HVAC specialists, utility workers, etc.). The company has also been a pioneer in the development of next generation lithium-ion battery technology for cordless power tools and accessories. Although the automotive market is only a small segment of Milwaukee Tool's sales, some of their products should appeal to both professional automotive technicians and do-it-yourself mechanics.

Pneumatic power tools such as impact wrenches, air ratchets, air drills, air hammers, grinders and sanders have long been the choice for serious automotive repair work. Pneumatic tools are powerful, reliable and save considerable time and effort compared to manual hand tools. But pneumatic tools have a few drawbacks. They require a compressor and an air hose to connect the tool to its power source. Hoses can be cumbersome to manhandle, and they create a tripping hazard. Air hoses can also develop air leaks. Air supply systems also require maintenance (filters to keep dirt out, and oil to lubricate the tools). And air tools can be very noisy (ear protection is recommended, even for occasional use).

Until the advent of today's high power lithium-ion battery packs and smart cordless power tools, cordless power tools have had minimal acceptance in the automotive service industry because cordless tools lacked the muscle and runtime required in a typical automotive repair shop environment. But all that has changed in recent years thanks to the development of high amperage, long life lithium-ion battery technology and smart tools that manage energy consumption to maximize runtime and performance. Many of these tools also have "brushless" permanent magnet motors that are smaller, lighter, more powerful and more durable than the previous generation of electric motors they have replaced.


You can now buy a cordless impact wrench that can deliver as much torque as most pneumatic impact wrenches (up to 700 ft. lbs. or more!). What's more, the battery pack contains enough energy to last all day in a typical shop. A high torque cordless impact wrench is a little heavier than a comparable pneumatic wrench, but there's no hose to drag around or trip over, and much less noise to bombard the ears when zipping off lug nuts or other fasteners. Better yet, some of the newest small cordless impact wrenches are actually smaller and lighter than a comparable pneumatic impact wrench, yet are capable of exerting over 200 ft. lbs. or torque, which is more than enough for rotating a set of tires on most vehicles.

For engine disassembly or other repairs, a cordless 90 degree right angle impact wrench can certainly compete with a traditional pneumatic air ratchet. Size, weight and torque are about the same, and as with the impact wrench there are no hoses or cords to get in the way.


Milwaukee Tool has been expanding their cordless M12 and M18 power tool product line for the past several years and have continued to push their REDLITHIUM battery technology to new highs. Although some cordless tool suppliers have gone to higher voltages (20, 24 & 28 volts) to extend the power and runtime of their tools (which requires buying new batteries that are usually incompatible with previous generation tools), Milwaukee Tool has been able to achieve even better results with continued enhancements to their M12 and M18 battery packs and tools. Most of the tools that were shown at the recent Milwaukee Tool media event significantly outperform competitive products that have the same or higher voltage and amp ratings.

One new product that was shown is a 9 amp M18 battery pack designed for high amp draw tool applications. The new battery pack will be fully backwards compatible with Milwaukee Tool's M18 cordless tools and chargers, and will nearly double the performance over their current top-of-the-line XC 5.0 battery pack. I like backwards compatibility because it means I can take advantage of the latest battery technology without having to replace all of my existing tools.

lithium battery packs cutaway
The new M18 battery pack in the foreground is rated at 9 amps
versus 5 amps for the M18 battery pack behind it.
The larger 9 amp pack has nearly DOUBLE the run time of the 5 amp pack.


Milwaukee Tool's latest revamp of their half-inch drive compact cordless impact wrench includes a smaller but more powerful brushless motor that delivers up to 20 percent more torque than the current model. The electronics inside the tool has also been redone and made smaller allowing the new tool to be slightly smaller and lighter than the current model. It's the same story for their latest line of drills and impact drivers.

The compact half-inch impact wrench has control buttons that allow for three different power settings (30, 75 and 200 ft. lbs. of torque). An engineer said the values are fairly accurate, but not as accurate as what you would get with a torque wrench. Even so, for the average user, close enough is usually good enough (although wheel lug nuts should always be final tightened with a torque wrench to the recommended specifications). Future models of this tool and other Milwaukee Tools will also feature a fourth button that will allow additional user adjustment capabilities (more on this innovation will be available at a later date).

cordless power tools cutaway
Brushless rare earth permanent magnet motors produce high torque.
The latest versions have updated electronics for longer run times.


Some of the phrases I kept hearing over and over again at the media event were "disruptive technology" (meaning their new tools are leapfrogging their competition and disrupting the market status quo) and "game changing innovation" (self-explanatory). From what I saw, I'd say these comments were not marketing hype or exaggeration. They were right on target.

Milwaukee Tool says that one of their goals is to "cut the cord", meaning they want their cordless power tools to replace most of today's corded power tools. I'd say they could also "cut the hose" as far as replacing many of today's automotive pneumatic tools with cordless power tools. The new smaller, lighter brushless tool designs, smart control electronics and longer-life lithium-ion battery packs are certainly capable of making that happen.

Milwaukee Tool cordless power tools
Some of the cordless power tools available from Milwaukee Tool


Another product that has real game changing possibilities is Milwaukee Tool's line of LED lighting products, including small handheld work lights as well as floodlights and telescoping tripod shop lights. LED lighting technology has come a long ways in recent years, with better light output and color control.

In the automotive world, incandescent trouble lights have been the most common light source for technicians who are working under the hood or under the dash. The trouble with incandescent lights is that the filament inside the bulb can be easily broken if the light it dropped or jarred. Also, the bulb gets quite hot and creates a potential fire hazard if fuel vapors are nearby. Hot bulbs also pose a potential burn hazard if you accidentally bump against one, which is easy to do when working in a cramped engine compartment or under the dash.

LEDs run relatively cool and create no burn or fire hazard. Also, they won't break if you accidentally drop a light or knock it over. Milwaukee Tool would like to see their cool running LED flood lights replace halogen shop lights. Halogen bulbs are typically rated at 250 or 500 watts and produce a lot of light. The latest generation of high output LEDs can produce More light for less wattage without the dangers and heat of a halogen lamp. The LED floodlights run at about 70 degrees F compared to over 600 degrees for a halogen light. LEDs are also rated for tens of thousands of hours of operation, and will far outlast any incandescent or halogen lamp. And with the new high capacity lithium-ion battery packs, the LED worklights and floodlights can provide many hours of illumination. The only drawback with LEDs is their higher initial price. But when you factor in what it costs to replace multiple halogen bulbs, or the consequences of a burn or fire, LEDs are a bargain.

2016 Update:

Cordless Power Tools Aim for Total World Domination!

At the 2016 Milwaukee Tool Product Preview, over 200 new products were introduced, and not one was a corded power tool. Many of the products are "next gen" versions of existing tools, upgraded with even longer run times, more features, reduced size and lighter weight.

Also included were several new LED lighting products, designed to replace portable halogen shop lights. Milwaukee is also expanding into the lawn care business with a new line of professional grade cordless weed trimmers, leaf blowers and hedge trimmers (available spring 2017).

Although Milwaukee Tool's primary focus is on the professional building trade user (plumbers, electricians, carpenters and utility workers), they continue to expand their offerings in the automotive market too. Their cordless impact wrenches, ratchets, drills, grinders, buffers and saws can match the performance of most pneumatic or corded electric tools.

Even more amazing is how their "ONE-KEY" smart tool program continues to evolve to meet the end user's needs. ONE-KEY adds Blue Tooth connectivity to more and more cordless power tools. This allows tools to be tracked, managed, secured and even customized on the fly using a free smart phone app. ONE-KEY allows you to use your cell phone to communicate with the tool to change its operating characteristics (RPM, torque, etc.), to monitor its usage (run time), to remotely turn a tool or LED lighting device on and off, and to even disable a tool if somebody walks off with it. How cool is that?

one-key video link

Milwaukee Tools says they not only want to "cut the cord" and replace all corded power tools with cordless tools, but to also "cut the hose" and replace pneumatic tools with their cordless counterparts.

With cordless tools, you don't need a noisy air compressor, air supply plumbing and a filtration/lubrication system, or the cost and maintenance required to maintain the pneumatics. There are no hoses to trip over, leak or replace. Getting rid of the hose also gives you a range of freedom and portability that just isn't possible with traditional pneumatic tools.

What about power and run times with cordless tools? The latest generation M18 Lithium Ion Fuel battery packs have the amps and capacity to deliver a full day's work on a single charge in most situations. The 9.0 amp M18 battery pack delivers almost twice the power and run-time of a 5.0 amp battery pack. Most users buy one or more extra batteries anyway, so swapping batteries if you're running low on power is no big deal. The M18 fast charger can charge up most battery packs in 30 minutes or less, and some chargers can charge several batteries at once.

Milwaukee Tool says they are committed to the M18 18-volt battery system for the foreseeable future, so don't worry about your tools becoming obsolete because the manufacturer changed to a different battery pack. Milwaukee Tool says they won't do that.

You can get just as much usable power with high amp capacity 18-volt lithium-Ion battery pack as you can with higher voltage 24, 36 or 48 volt battery packs. It's how the power is managed and delivered that makes the difference. With Milwaukee Tool's smart electronics, battery power is managed to extract the most usable power for the longest period time while protecting the tool against dangerous overloads and overheating. That's their secret to delivering such great performance and durability with cordless power tools.

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