Tool Review: Mighty Seven 1/2” Air Impact Wrench

Feb. 13, 2018
The reviewer says this impact can be used in spaces full-size impacts cannot.

The Mighty Seven 1/2” Air Impact Wrench, No. NC-4256Q, provides users with 1,100 lb-ft of maximum reverse torque in five seconds. The impact is designed with a twin-hammer mechanism with an aluminum body, which the company says is reliable and suitable for long operating cycles. The NC-4256Q is 5-1/2” long and weighs 3.94 lbs, allowing access to confined areas and less user fatigue. The molded composite handle is ergonomically designed for operator comfort, and is quiet at 85 dBA, which meets OSHA safety standards. The tool runs at 9,000 rpm. A 2” extended anvil option is also available.

The Review

Working in tight spots with a small form 1/2" impact wrench doesn't have to mean sacrificing power.

Using the Mighty Seven 1/2” Air Impact Wrench, Lou Fort, lead technician at K.A.R.S. Inc. in Huntingburg, Indiana, was able to complete suspension work in cramped spaces he previously could not use a 1/2" impact in.

"I have other small form 1/2"  impacts that would fit into such spots, but they don’t have the punch M7 has crammed into this impact," Fort says.

Fort also put the impact to the test removing lug nuts, crack bolts and rebuilding differentials. While he says he prefers using a cordless impact for removing and installing wheels, he says the M7 is "up to the task" when it comes to differential jobs.

"The NC-4256Q didn’t even whimper pre-torquing crush sleeves," Fort says.

An impact like this one featuring three power reverse settings is a first for Fort, who has only come across impacts, full-size or not, with a single reverse power setting.

 "The different power levels in reverse let me use just one air tool during disassembly work with little fear of breaking off a frozen fastener," Fort explains. "Things like exhaust manifolds to pipe nuts, start out on low. If it moves, step it up to whip them off with the impact’s lightning speed."

Trigger controls on this impact are "smooth and easy to feather" in either direction or power setting, Fort adds.

As for comparisons, Fort says he has faster impacts in his toolbox but notes that 9,000 rpm is "impressive" at this power level.

"I just love the amount of power they have squeezed into this small package," Fort says of the NC-4256Q.

Built with solid metal through and through, with no composites in the housing or hard working guts, the impact can take some time to get used to.

"At first, I was taken aback at the weight of such a small impact," Fort explains. "At just under 4 lbs it is still heavier than my full-size impacts. This is due to M7 using a full metal frame – no composites here, boys and girls. [The weight], however, has become a non-issue as I have become used to it."

The tool also features a soft cushion grip. Although Fort likes the comfort, he notes that he is concerned about how long it will last, seeing as the grip has become a "tad loose" after use.

Fort’s only other concern, although he shrugs it off as a minor issue, is that after a few uses he had to replace the socket ring. After replacement, though, the tool held up with "no trouble whatsoever," Fort explains.

"I'm thinking I just got a bum ring," Fort says. "I did not contact M7 about it because, well, it happens and it’s easy to fix."

Overall, Fort is impressed with the power of the small impact.

About the Author

Vesna Brajkovic | Associate Editor - Vehicle Repair Group

Vesna Brajkovic is a former associate editor for the Vehicle Repair Group.

Brajkovic has covered the transportation industry for a number of trade publications, with a focus on the vehicle maintenance and automotive aftermarket industries since 2016. Prior to that, she covered the global aviation industry as assistant editor for Endeavor Business Media's AviationPros.com, and held a number of editorial positions at an award-winning community newspaper.

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