Impact Wrench versus Impact Driver

[Techniker]

So on the most recent discussion where everyone posted their impact wrench pictures, I saw a lot of people posting pictures of what were actually impact drivers. Having never actually owned an impact driver myself, I was under the impression that they were basically a high-torque drill. Then I saw a picture someone posted that was actually an extension/converter that converted the 1/4" hex into a 3/8" square drive and he had a wobble socket attached to that? Is that correct or am I making that up?

So what is the advantage of having this tool (from an automotive technician standpoint) versus a regular 1/2" square drive cordless impact wrench? What would it do to complement the cordless impact wrench (if anything)?

Thank you in advance,
Techniker

 

[I can fix anything]

You get downward pressure, and that helps "shock" screws loose.

 

[Techniker]

You get downward pressure, and that helps "shock" screws loose.

Thanks for the response. Are you talking screws as in woodworking here or for bolts? Though I guess the principle should be the same regardless.

I'm just having a hard time imagining how it is any different from a drill since the only time I have ever had any marginal interaction with one was in a Sears store. I turned it on and it pretty much seemed like a compact, high-torque drill with a different drive to me. I didn't really see anything that would give it downward pressure?

-Techniker

 

[I can fix anything]

My bad I thought you meant an impact driver that you hit with a hammer.

 

[I can fix anything]

Square drive hits harder.

 

[MrMark]

You get downward pressure, and that helps "shock" screws loose.

HE's talking about the battery impacts that have a female quick release hex output rather than the typical "wrench" impacts that have a normal square drive.

The ones the OP saw were impacts, just the same as the square drive versions, but set up to drive screws, usually. They have enjoyed wide spread popularity as a noisy construction tool for screws. Not sure why, really. They are a little faster but they offer no tactile feedback so they are only good for rough construction.

Those battery impacts can use a hex to square drive adaptor and then you have essentially the same thing but it is not as good as having the wrench with the square drive because the adapter adds woble.

 

[Techniker]

Square drive hits harder.

Sorry, yeah, I was talking about something like this:

 

[Techniker]

HE's talking about the battery impacts that have a female quick release hex output rather than the typical "wrench" impacts that have a normal square drive.

The ones the OP saw were impacts, just the same as the square drive versions, but set up to drive screws, usually. They have enjoyed wide spread popularity as a noisy construction tool for screws. Not sure why, really. They are a little faster but they offer no tactile feedback so they are only good for rough construction.

Those battery impacts can use a hex to square drive adaptor and then you have essentially the same thing but it is not as good as having the wrench with the square drive because the adapter adds woble.

Okay, so really there is no advantage then over a real full 1/2" impact wrench? Also, I assume the torque isn't as high either?

 

[MrMark]

Okay, so really there is no advantage then over a real full 1/2" impact wrench? Also, I assume the torque isn't as high either?

Absolutely not. There is a total disadvantage for auto use where you want to put a socket on the end. With regard to the torque, it's hard to say. Generally I think you are right. The wrenches seem to have a higher output rating than their impact "driver" cousins.

 

[MrMark]

Sorry, yeah, I was talking about something like this:

You know you can get a hex to square adaptor for that and you can get a square drive to hex adapter for the "wrench" version if you want to use the wrench to drive screws like for deck building.

 

[honcho]

Impact Drivers (the ones normally with the 1/4 hex bit chuck) are largely derived from generally more powerful impact wrench. Cordless drill / drivers work well on many screws but just didn't have the "oomph" necessary for driving larger screws / lag bolts, especially without drilling pilot holes. Adapting the hammer and anvil of the power impact wrench to a lightweight cordless tool became the impact driver.

If you compare the specifications of the various impact drivers against drill / drivers and impact wrenches you'll find that the impact drivers can deliver more torque than similar voltage (for cordless tools) drill / drivers and less torque than impact wrenches.

For construction / assembly purposes, the downside of impact drivers (and impact wrenches) is the lack of a torque limiting clutch mechanism to prevent the user from just pounding a fastener deep into the surface. This isn't as much of a problem for mechanical use but, like with using any impact tool, excessive torque can damage fasteners or the items being worked-on.

Particularly for disassembly of items with lots of fasteners (think dashboards) the small impact drivers are terrific tools. I use mine for as kind of a powered speeder wrench. It produces 800 lb/in of torque which is about 65 lb/ft. It is very compact and lightweight. Bosch PS40

 

[dr_clyde]

like previously stated, anything with lots of fasteners that don't need heavy torque, those things rock. The one I have you can get it configured as either a 1/4" hex or a 3/8 square and for me, it beats having to get out the air tools for small stuff. I also use it for driving long screws into 4x4s or stuff like that.

 

[petee_c]

You get downward pressure, and that helps "shock" screws loose.

I think the impact is rotational, not downwards.... I have a Makita 18V one, and it's great for driving screws in a construction/renovation setting. I think I saw a schematic/how it works article in either WOOD or Family Handyman.

I have used mine on the car because it is smaller than my electric corded impact wrench. Used it to spin off rusty suspension nuts. It was a nut that was hard to spin off because of rust, and there was only enough swim to move 1/8th of a rotation with a ratchet or gearwrench.

Ideally, I'd like a 3/8" air ratchet, but I can wait for one to go onsale.

P

 

[demographic]

For construction / assembly purposes, the downside of impact drivers (and impact wrenches) is the lack of a torque limiting clutch mechanism to prevent the user from just pounding a fastener deep into the surface.

To be fair, you have to be fairly cack handed to drive it deep into the work.
I have a Hitachi impact driver and its a great little tool.
I tentd to use a bit of trigger controll on normal drill drivers anyway and hardly ever bother with the torque settings as its usually going into wood and its not that reliable in the smaller screws.

No getting round the fact that when driving big screws in its very loud though.

 

[Hip2u77]

IMO, the best thing about an impact driver is how it's far less likely to strip out a screw head. Anyone that's ever fought with a rusted screw knows hows frustrating it can be when you barely try to turn it and the head wants to strip out. An impact driver will minimize that.

I've got the Bosch PS40, M12 Milwaukee and even the Ridgid right-angle one. And while all these are rated at 750 - 850 in. lbs of torque honestly not a one of them will drive a 1/4" lag as easy (or as fast) as a Ridgid drill that only has 350 in lb of torque.

But they're gold when it comes to rusted screws. (A few weeks ago I replaced the wear blade on a 30-year-old Toro snow blower and that was another incident where one came in handy.)


For auto work they come in handy for anything interior related. Especially the Bosch one since it has a ring of 3 LED lights around the nose.

 

[cortez]

Works good on rusted screws?? That's all I needed to hear, I'm going to get me one of them!!

 

[usdemt]

I got one for my grandfather and he loves it because it is much easier on his arthritic wrists and hands. They are much louder though.

I have one of each and prefer the impact to the driver, it has more torque. But when driving screws I will go to the drill or driver. Another advantage to the drivers to a drill is that they are shorter with no clutch or long chuck.

 

[mikevango]

I have the makita 18v lithium impact driver. Use it for driving screws and with a 3/8 socket adapter. It's rated at about 90 ft pounds or so. I can remove lug nuts with it

 

[Just_Locin_by...]

I find this thread interesting because I am currently looking for an impact wrench for automobile use however, because of searches, have since discovered impact drivers. According to a tool website, the "Bare 1/4 in. Volt Cordless Impact Driver has 850 in. lb. of torque for work on decking, fencing, drywall or pulling apart engines" and the "1/2 in. Electric Impact Wrench has 230 ft. lb. of max torque". This doesn't seem to corroborate with what I see posted in this thread/forum. Have things changed this much over the years? I don't want to purchase the wrong tool. Also, is there a way to use the impact socket bits with the impact driver? Impact driver appears to be female whereas impact driver is male but would like the tool with the most torque. Please forgive the extra long post. Thank you for your insight.

 

[krdiesel03]

if you are taking off large bolts, lugnuts you need a 1/2 impact wrench, but they are heavy. if you are working on smaller stuff a lighter impact driver is nice.

Lets look at the cman C3 impact driver, it is 1500 Inch pounds, that is 125 FP
The 1/2 impact wrench is 240 foot pounds and made to take true impact sockets.

 

[Wakefield]

The small electric impact drivers and the hand impact drivers such as the Snap On PIT 120 and KoKen Attack Driver are not quite the same thing? But almost? The hand drivers best for stubborn Phillips screws? Is the FBS9 which converts the 3/8" drive of the PIT 120 to hold 5/16" hex bit strong enough not to break? (I hope)

 

[rlitman]

I find this thread interesting because I am currently looking for an impact wrench for automobile use however, because of searches, have since discovered impact drivers. According to a tool website, the "Bare 1/4 in. Volt Cordless Impact Driver has 850 in. lb. of torque for work on decking, fencing, drywall or pulling apart engines" and the "1/2 in. Electric Impact Wrench has 230 ft. lb. of max torque". This doesn't seem to corroborate with what I see posted in this thread/forum. Have things changed this much over the years? I don't want to purchase the wrong tool. Also, is there a way to use the impact socket bits with the impact driver? Impact driver appears to be female whereas impact driver is male but would like the tool with the most torque. Please forgive the extra long post. Thank you for your insight.

First off, 1 ft-lb = 12 inch-lbs. So your 230 ft-lb impact wrench has 2760 inch-lbs of torque.

As said above, the 1/4" hex shaft gives less torque than a 3/8" square.
I have an M18 Milwaukee Fuel impact driver (1/4" hex). The 3/8" square drive impact wrench version of the same tool has almost a third more power. Why? Because the 1/4" hex shank of the tool will twist a little bit with each impact, like a spring. That limits how much torque the tool can deliver.

The same thing is true with a 1/2" impact gun. You get more power when driving the socket directly, than when driving it through a long extension.

Personally, I don't mind that my impact driver has a little less torque, as I can always step up to a real pneumatic tool when I need the power. And I prefer that the longer 1/4" hex has less wobble than a square drive.

Either one you get, there are adapters to do the other. Unless you get one of those really cool Bosch deals that are a combination 1/4" hex / 3/8" square.

 

[Skin]

The small electric impact drivers and the hand impact drivers such as the Snap On PIT 120 and KoKen Attack Driver are not quite the same thing? But almost? The hand drivers best for stubborn Phillips screws? Is the FBS9 which converts the 3/8" drive of the PIT 120 to hold 5/16" hex bit strong enough not to break? (I hope)

Basically. Impact wrenches will destroy a philips fastener from the repeated hammering if its stuck enough. Impact drivers are all about downward pressure, relieving the tension/stress on the threads, so the chances of cam out or otherwise tearing the Philips fastener up are pretty miniscule. You can snap them right off though.

I tend to prefer old school impact drivers for anything like frozen philips, flat, and small hex or torx screws (t-stat housings, sensors etc..). Seems to preserve both the fastener and the bit socket the best. Hex fasteners don't benefit from hand impact drivers if there is no shoulder and even on a bolt or nut that has one you're still losing quite a bit of your energy since its not being focused straight down the threads unlike a hex/torx/Philips head where you're hammering down on center.

 

[Monte]

So on the most recent discussion where everyone posted their impact wrench pictures, I saw a lot of people posting pictures of what were actually impact drivers. Having never actually owned an impact driver myself, I was under the impression that they were basically a high-torque drill. Then I saw a picture someone posted that was actually an extension/converter that converted the 1/4" hex into a 3/8" square drive and he had a wobble socket attached to that? Is that correct or am I making that up?

So what is the advantage of having this tool (from an automotive technician standpoint) versus a regular 1/2" square drive cordless impact wrench? What would it do to complement the cordless impact wrench (if anything)?

Thank you in advance,
Techniker

for automotive use i would get a 1/2" impact wrench...it´s better...

<iframe width="420" height="315" src="//www.youtube.com/embed/rdnOxaznvzQ" frameborder="0" allowfullscreen></iframe>

 

[vinnythestick]

Basically. Impact wrenches will destroy a philips fastener from the repeated hammering if its stuck enough. Impact drivers are all about downward pressure, relieving the tension/stress on the threads, so the chances of cam out or otherwise tearing the Philips fastener up are pretty miniscule. You can snap them right off though.

I tend to prefer old school impact drivers for anything like frozen philips, flat, and small hex or torx screws (t-stat housings, sensors etc..). Seems to preserve both the fastener and the bit socket the best. Hex fasteners don't benefit from hand impact drivers if there is no shoulder and even on a bolt or nut that has one you're still losing quite a bit of your energy since its not being focused straight down the threads unlike a hex/torx/Philips head where you're hammering down on center.

 

[NoahG]

I use 2.5" and 3" drywall and wood screws by the bucketful. Impact drivers take all the stress off my shoulder and wrist. I had a coworker with a bunch of elbow problems and he was sold on Impact Drivers in the first 5 minutes of using mine. For 1 5/8" and less, sometimes I'll go with a regular drill/drive, but my Impact Driver does have a torque selector, and being a conscious user, I don't just blast away at every fastener till it stops moving.

 

[djb2]

Note that this threat was brought back from the dead by a confused new user.

There was a little confusion in the original thread about a hand impact driver -- the kind you hit with a hammer -- and a battery power impact driver. The original question was why some battery powered impact tools were called drivers rather than wrenches.

The ones called drivers tend to be have 1/4" hex drive rather than square drive, and have a non-anvil-impact mode until higher torque is needed.

Impact drivers are great tools. They weren't needed when battery powered drill/drivers were low torque. But now battery tools can put out arm-twisting, hand-smashing torque that can do real damage when a fastener suddenly grabs. The impact mode is "reactionless", eliminating this problem.

 

[Westly]

The little hex drive electric impacts usually built into drills are dangerous to have around. They're meant to be used on screws mainly but nothing will strip a screw head faster.

A hand impact driver avoids that problem because the turning motion is accompanied by a downward force, both coming from the hammer blow. It's hard to strip a screw head with it because of the downward blow from the hammer into the head. Hard but not impossible; a really stuck screw made of really soft metal will still strip.

 

[Farmall450]

My bad I thought you meant an impact driver that you hit with a hammer.

Same here.

 

[pauls_workshop]

I have now both a 1/4" cordless impact driver and a 1/2" cordless impact driver just recently acquired, both in Ryobi 18v formats. The 1/4" is great for woodworking, driving up to about 3" screws into wood, predrilled or similar. I have used it on the cars for various things and loosening/tightening up to 1/2" bolts with it, but it has about 1500 in pounds of torque. Can't do things like lug nuts on wheels with this. This type of 1/4" impact driver is the only way to install drywall after I've used it on my basement project. Use screws not nails in drywall and use one of these type drivers to do it fast and easy. You could easily use the 1/4" impact driver with a 3/8" end for 3/8" sockets and would work fine. You could also use a 3/8" end on the 1/2" size impact driver too, but risk overtorquing/breaking 3/8" size sockets with that (see below) so woul dhave to be careful there.

I got the 1/2" with 200 ft pounds ability to handle any bigger job and auto use, but also for bigger woodworking uses, for long big bolt driving or loosening or whenever needed. You would not want to use that for all needs, as the 1/4" size covers the smaller bolt or screw tightening or loosening needs much better than the big one and much lighter to hold. Risk is the big one will drive things in too far too quickly or to too high a torque. It also is heavier to use all the time. Two tools to do the jobs. An air powered impact would be more powerful by far with a good compressor, but for occasional (not a pro mechanic) use, the 1/2" battery powered impact driver will cover most of my needs well as my homeowner big dog tool. For final torquing of any critical fastener, a torque wrench by hand must always be used to set the proper torque. You don't want too little or too much torque on any critical joint. These are to either loosen or to get you close to final torque but not all the way. For non-critical joints, I just use the 1/4" impact and let it finish the job. If I very very rarely need more torque to loosen a fastener than the 1/2" impact can do, then pull out that two foot long 1/2" Harbor Freight manual breaker bar for that.

Also, use IMPACT sockets with any impact wrench/driver to avoid sockets breaking. Impact sockets are different than normal chromed sockets and made to take impact loads. Chromed normal sockets might work fine, but can also break and do sometimes and are dangerous as a result. Impact sockets won't break. Similarly, use normal chromed sockets for normal (non impact) hand wrenching as they are best for that use. Also, the above Ryobi impacts are the same as Craftsman C3. Ryobi rebadges all the Craftsman C3 tools and makes them all. C3 has slightly different battery than Ryobi, but guts are same and tools are same. - Paul

 

[jdmstr]

So on the most recent discussion where everyone posted their impact wrench pictures, I saw a lot of people posting pictures of what were actually impact drivers. Having never actually owned an impact driver myself, I was under the impression that they were basically a high-torque drill. Then I saw a picture someone posted that was actually an extension/converter that converted the 1/4" hex into a 3/8" square drive and he had a wobble socket attached to that? Is that correct or am I making that up?

So what is the advantage of having this tool (from an automotive technician standpoint) versus a regular 1/2" square drive cordless impact wrench? What would it do to complement the cordless impact wrench (if anything)?

Thank you in advance,
Techniker

yes you can use a 3/8 or even 1/2 adaptor with these. i have a Bosch PS-41 that makes 930 in lbs of torque or 77ft/lbs. They don't make as much power as the 1/2 square drive but they are also more compact and are good for engine work or interior work.

 

[rick carpenter]

HE's talking about the battery impacts that have a female quick release hex output rather than the typical "wrench" impacts that have a normal square drive.

The ones the OP saw were impacts, just the same as the square drive versions, but set up to drive screws, usually. They have enjoyed wide spread popularity as a noisy construction tool for screws. Not sure why, really. They are a little faster but they offer no tactile feedback so they are only good for rough construction.

Those battery impacts can use a hex to square drive adaptor and then you have essentially the same thing but it is not as good as having the wrench with the square drive because the adapter adds woble.

I hung drywall for a week straight with my Bosch 18v impact driver. I had very few screws driven through or left proud. All you have to do is learn when to stop driving. Easy. Others may disagree but my buddy and I got 'er done just fine. I even converted him away from a drill/driver for drywall to an impact driver.

As for others' comments, the impact action on these tools is rotational. They work great for driving phillips heads because the impact action lets the bit reset each time for fewer cam outs. The other advantges are the shock effect, as one poster mentioned, and the greater torque.

Much much better for driving (any) screws than a drill/driver imo.

 

[monomach]

Okay, so really there is no advantage then over a real full 1/2" impact wrench? Also, I assume the torque isn't as high either?

The only good reason for using an impact driver to do an impact wrench's job is not having access to an impact wrench.

It's a poor substitute.

I find this thread interesting because I am currently looking for an impact wrench for automobile use however, because of searches, have since discovered impact drivers. According to a tool website, the "Bare 1/4 in. Volt Cordless Impact Driver has 850 in. lb. of torque for work on decking, fencing, drywall or pulling apart engines" and the "1/2 in. Electric Impact Wrench has 230 ft. lb. of max torque". This doesn't seem to corroborate with what I see posted in this thread/forum. Have things changed this much over the years? I don't want to purchase the wrong tool. Also, is there a way to use the impact socket bits with the impact driver? Impact driver appears to be female whereas impact driver is male but would like the tool with the most torque. Please forgive the extra long post. Thank you for your insight.

Inch pounds and foot pounds are not the same thing, silly.