In a comment to our post about the new Milwaukee M18 impact wrenches that came out last year, a reader asked a question that has come up a couple of times:
What is the M18 FUEL 7/16″ Hex High Torque Impact Wrench Kit (2765-22) used for , googled it & hardly anything comes up.
So what are 7/16″ large hex impact drivers and wrenches used for? Generally, they are most often used with larger-sized drill bits in the construction industry.
These larger impact tools are especially favored by field professionals in certain specialized industries, such as those in electric power, telephone, and other utility sectors. That’s why many 7/16″ hex impact wrenches have robust tether attachment points – to avoid tool loss while a worker is up on a utility pole.
Larger and heavy-duty styled drill bits, such as Milwaukee’s self-feeding bits (more info) and Bosch’s Daredevil Auger bits (more info) are built with 7/16″ hex shanks.
1/4″ hex impact drivers can be too puny to drive these monstrous bits, square drive impact wrenches are often optimized for use on fasteners, and 1/2″ drills – even if powerful enough – could subject users to dangerous counter-torque forces should a large drill bit jam or bind during use.
The huge reactive torque created when a large drill bit jams can be enough to twist or break your wrist, even if you’re being careful. This is something that should be avoided when working on stable ground, and so you definitely don’t want this happening to a worker when he’s working above ground such as on a utility pole.
Although less common, a number of brands manufacture 7/16″ hex shank screwdriver bits that also fit these impact drivers. You won’t find anywhere as broad a selection as with 1/4″ hex bits, and even 5/16″ hex bits, but they fit without the need for adapters – which are also available.
Do you use 7/16″ hex impact drivers or wrenches for any other applications? If so, please let us know in a comment!
Were you able to find any specs on what size self feed bits they can handle?
I’ll see if I can find that out. But given how long utility pole drills are, I would think that this impact could handle any bit that’s built with a 7/16″ hex shank.
Home Depot also sells a hole saw arbor w 7/16″ hex shank. Milwaukee. These are a great option to turn down to .375″ for use in a 3/8 collet on a mill.
Hadn’t thought about them for big drill bits. I guess until now, I didn’t know what they were for, as I assumed the next step up from an impact driver was a 3/8 impact. Thanks for farhtering my tool education.
One, maybe two years ago, I didn’t know what they were used for either. My memory was fuzzy, so I double checked when writing the post. We should thank Rick for the great question!
Linemen tend to use them
Bloody awesome tools. We usually use it for drilling big augur bits through hard wood cross arms. Can do it with one hand at awkward angle not having to worry about broken wrists
Good to know, I was wondering that myself but then seen a couple of Bosch bits that used huge hex shanks so I assumed that’s what they were good for
Anyone ever try spinning a hole saw with one of these? Seems like it could be nice for an electrician.
Tired it with mine once broke a brand new arbor
Where did it break? on the 7/16 shank or where the arbor connects to the saw bell?
I once saw a guy get his wrist broken while drilling a hole with a 1/2″ Milwaukee corded and a 2 1/8″ holesaw. The harder you lean on them the greater the torque reaction if they bind. Be careful out there!
That’s why I’m so curious about these. That shouldn’t be as much of an issue with an impact driver.
Been an electrician for almost 30 years, and have yet to meet or hear of anyone who’s actually broken their wrist with a Hole Hawg or other high-torque drill. A little common sense goes a long way, plus we tradesmen aren’t built like accountants, no offense to accountants. It’s more of a thing the old guys tell the young guys, to scare ’em.
Oh, and while I plan on trying one of these sooner or later, they do make a 7/16″ hex adapter for a 1/2″ anvil, so a high-torque impact wrench should be able to be similarly utilized.
Some line construction crews in my neck of the woods eschew corded electric tools altogether and don’t seem to have yet adopted cordless tools (perhaps a anti-theft mentality on the part of the utility). After Hurricane Sandy – I noticed crews using hydraulic tools – not sure what brand – but here’s a link to Greenlee:
I am a plumber and i use this drill daily with the 2 5/8 milwaukee self feed bit. It work faster and safer than my old corded angle drill. the only con is the noise, the wood mess u do on your cloth and the fast use of the edge of the bit.
im a telco lineman for a major communications company. all the impacts we use are 5/8″ hex drive. Milwaukee makes a corded version of this, and use to make a cordless however i cannot find one now.. 5/8″ hex is an even more rare size, and is almost impossible to find anything other than a few basic attachments for. 7/16″ hex, which is favored by power companies, is actually much more popular, and a pretty decent assortment of items are made to fit that.. i actually wish my company would switch over. would also be nice if Milwaukee would make a fuel version (or any version) of a cordless 5/8″ hex drive now.
Lenox makes a few hex adapters i know they have 1/4, 3/8, and 7/16 hex drive adapters. Maybe time to change out as there are a lot of 7/16 stuff.
Apex is another industrial tool company that has drive tools and adapters. Every electrician knows what an Apex bit holder is.
I read in a forum about the 7/16″ hex and had to google it. Found this write up.
I can see how these are becoming more popular as the torque on these tools starts to increase.
Masonry wall ties ,heavy-duty ones of course
It’s an electronic version of an hydraulic acklee gun used for drilling on utility poles ( wood power poles)
We used them with a selection of specialized bits for installing buckles (clips) on conveyor belts. The buckles can be used to join two ends of a belt or to repair rips or small holes.
Hey, were can I find 7/16 shanked impact bits and affordable and will ship abroad. My main concern is finding one to drive 5mm hex buggle screws. Iv got by with adapters but it would be nice to simplify it as i do such volumes of them. Apex bits make the bit im after but unfortunately they do not ship abroad. Any recommendations would be much appreciated.
I’m a plumber and I use to drill lists
Large holes through joists
I use one of these as an agricultural fencing contractor. Often need to drill right through an 8 or 10 inch pressure-creosoted gate post to fit a hinge. Takes a toll on even the beefiest cordless drill, and the augers can bind up too. It also negates the need to carry a drill and an impact driver/wrench, as the one tool can also drive the big coach screws for latches, locks, plate hinges, etc. I used to use a 1/2″ square with an adapter, but it would often pull off and leave the auger in the hole!