Impact wrench

[Wayne Orwig]

I should have thought of this earlier. Someone might have gotten me this tool as a Christmas gift. 

Being a cheapskate (Guzzi content), years and years ago, I bought a cheap 1/2" Harbor Freight air impact wrench. It generally does what I need, but I know it isn't that powerful. Then, maybe 10 years back, I needed to change the clutch in my daughters car. But there were a couple of bolts in the bell housing that refused to move. I did some quick online searching, and a nearby Autozone had a highly rated air impact gun. I sent my daughter to get that while I continued working. So it turned out, that this new highly rated impact wrench did not help. And in fact, felt like it had less power then the cheap Harbor Freight model.

Well, today, I was doing some searching. Just for grins. I was looking a Home Depot, and the Ryobi brand. Since I have a load of those tools, and batteries, and I am happy with them. But there best model is rated at 300 ft/lb , I think it was. And if I go to Harbor Freight, they have some rated at like 1500 ft/lb.

So, are the Harbor Freight specs total BS. Is it possible they are close to correct, but only if you have a 400PSI compressor driving it?

Tell me about impact wrenches? And I suspect I do not really want another battery to charge, but I also don't want to replace my old 120PSI compressor. I just want to very occasionally put some hurt on a stuck bolt.
 
On the clutch. I just put the car back together, and a month later when visiting my brother, we replaced the clutch. He has all Snap-on tools. His air impact wrench did not even hesitate on those bolts. But that one wrench probably cost more than my entire toolbox full of Craftsmen tools, so that isn't happening.

[RinkRat II]

     I have  a Chicago Pneumatic 1/2' drive with a extended anvil ( designed for tire work) that I bought in 1974. It has never let me down and I have religiously lubed it every third or fourth use.  Recently I bought a package deal from Bosch that came with an electric drill driver and 1/2" impact wrench. I can honestly tell you  that the Bosch is every bit as powerful and has removed some bolts that I thought I was going to need the CP to get off. Highly recommended Mod#GDX18V-1600 impact, the drill driver eh, not so much. Kit came with the tools, batteries and charger and case for $150.00.  Good Luck!

      Paul B

[Ratso88]

It's really subjective. I have a few impact wrenches and drivers. One for each job I suppose.

The 1/2" drive is an Ingersol Rand I bought in '79 when I got my first mechanics job. Still going strong.

Also have 3/8 drive butterfly, 1/4 drive electric and 3/8 drive smack it with a BFH type.

I have no experience with any larger electric impacts but 1500 ft/lbs would probably twist your arm off. Maybe it's in/lbs?

I've use 3/4 drive air impacts for heavy diesel and that'd be it for me.

Higher torques at work we use a torque multiplier.

[egschade]

I have a Ryobi 18v cordless which is rated at 300lbs. Does OK but can't handle heavy stuff like over tightened wheel lugs. Had a 1200 lb pneumatic wrench that did much better but it went away with my large compressor. The pancake I have now doesn't push enough air.

[kballowe]

Air pressure/volume turns a cheap air impact tool into a respectable one. 
My go-to is an old off-brand 1/2" and it works well as long as you have 120 PSI in that 40 gal tank.

Doesn't work worth a hoot on my little pancake compressor.  It's got the PSI but lacks the volume.
OK, well if it comes loose in the first five or six ca-chunka ca-chunka's then it's OK

[lucky phil]

The question is how are impact guns rated, by which methodology. It's a fair question and I dont know, but if you look at the myriad of variables involved in getting a specific torque applied to a fastener with a simple torque wrench I suspect the way different manufacturers rate their impact guns is going to be more smoke and mirrors than science.

Ciao

[SIR REAL ED]

The question is how are impact guns rated, by which methodology. It's a fair question and I dont know, but if you look at the myriad of variables involved in getting a specific torque applied to a fastener with a simple torque wrench I suspect the way different manufacturers rate their impact guns is going to be more smoke and mirrors than science.

Ciao

It is the impact that generates the higher torque.  Remember not being able to loosen a bolt by pulling on the wrench, then loosening the bolt easily by smacking the wrench with a hammer.  Same principle.

The ratings are real.  Also the torque goes up with the number of hits.  Letting the impact wrench pound for 20 seconds yields a higher torque than only five seconds.  Watch the socket and see how it continues to turn with more hits up to the maximum torque at some duration of time.

I have a Ryobi 18V rechargeable rated at 300 ft-lbs.   Almost always does the job.

I've been tempted to augment it with a rechargeable Milwaukee rated at 1500 ft-lbs, but too many $. If I ever need more torque, I'll probably get a cheap 120v impact wrench.  Just like other electric tools, the plug into the wall types have "a lot more ass" than the rechargeable ones. 

Learned that lesson with a 1/16" cutoff wheel the other week. 18v tool will cut a little for 10 minutes or so then it needs a recharge.  With the 120 v tool you can lean on it and "let er eat!" and burn up an entire wheel without the grinder getting too hot and dying.

The other trick with impacts is to always minimize slop between the wrench and the nut/bolt head.  Put on three extensions then the socket and it won't tighten or loosen worth a damn.  Put the socket directly on the wrench and you get the impacting power back.

If you ever can't get something loose with your impact wrench, grab the socket/extension closest to the wrench with your free hand and twist it as hard as you can in the direction of loosening.  By taking out the slop, the impacts are more efficient and suddenly, your impact wrench has a lot more torque than just a few seconds ago, even though realistically, you've probably only added 10 ft-lbs or less with your hand.

Done that lots of times, especially if you have no choice but to use multiple extensions/adaptors.  You can pound on it all day without result, do the hand twist to take out the slop and boom, you're done.

[Ncdan]

I have a 50 year old electric 1/2” drive impact that has never failed to break loose any nut I’ve ever put it on. This includes 1 13/16 bush hog blade bolts that’s not been removed in years. I hope it last as long as I need to break hard to budge nuts😉

[lucky phil]

It is the impact that generates the higher torque.  Remember not being able to loosen a bolt by pulling on the wrench, then loosening the bolt easily by smacking the wrench with a hammer.  Same principle.

The ratings are real.  Also the torque goes up with the number of hits.  Letting the impact wrench pound for 20 seconds yields a higher torque than only five seconds.  Watch the socket and see how it continues to turn with more hits up to the maximum torque at some duration of time.

I have a Ryobi 18V rechargeable rated at 300 ft-lbs.   Almost always does the job.

I've been tempted to augment it with a rechargeable Milwaukee rated at 1500 ft-lbs, but too many $. If I ever need more torque, I'll probably get a cheap 120v impact wrench.  Just like other electric tools, the plug into the wall types have "a lot more ass" than the rechargeable ones. 

Learned that lesson with a 1/16" cutoff wheel the other week. 18v tool will cut a little for 10 minutes or so then it needs a recharge.  With the 120 v tool you can lean on it and "let er eat!" and burn up an entire wheel without the grinder getting too hot and dying.

The other trick with impacts is to always minimize slop between the wrench and the nut/bolt head.  Put on three extensions then the socket and it won't tighten or loosen worth a damn.  Put the socket directly on the wrench and you get the impacting power back.

If you ever can't get something loose with your impact wrench, grab the socket/extension closest to the wrench with your free hand and twist it as hard as you can in the direction of loosening.  By taking out the slop, the impacts are more efficient and suddenly, your impact wrench has a lot more torque than just a few seconds ago, even though realistically, you've probably only added 10 ft-lbs or less with your hand.

Done that lots of times, especially if you have no choice but to use multiple extensions/adaptors.  You can pound on it all day without result, do the hand twist to take out the slop and boom, you're done.

I'm not debating the fact they work to a greater or lesser effect and how just the rating methodology. Whats the accepted testing/rating standard?

Ciao

[SIR REAL ED]

I'm not debating the fact they work to a greater or lesser effect and how just the rating methodology. Whats the accepted testing/rating standard?

Ciao

I really don't know who controls the rating system.  I'm sure ASTM or SAE has some standards.  Search engine time.

I don't even know if the rated torque is achieved after 3, 5, 10, or 30 seconds of pounding.

[RinkRat II]

  In the USA the ANSI(American National Standards Institute) oversees the specifications produced by the HTI(hand tool institute) a cosortium of manufacturers basically policing themselves and providing their own tests.  As long as the tool gets an ANSI rating you are assured it has undergone testing and achieved a certain rating.

        Paul B

[wymple]

I bought one this year, and after researching a bunch, I bought the DeWalt 1/2 inch cordless. It had the most rated torque I could find, somewhere around 1200 ft lbs. Anything bigger required an air compressor, and a good air compressor at that. No way that hose was getting dragged around. I haven't seen the lug nut it can't handle, and that included some fused on with rust. I'd do it again.

[Tom]

I've been using a plug in electric Harbor Freight one.  Works better for me than the air/w air compressor.  I string an extension cord versus running air lines and starting up the air compressor.  Not sure about the battery powered impact wrenches.

[bmc5733946]

Air powered impact wrenches can have 1 or 2 hammers in the impact mechanism. As a general rule Ingersoll Rand have 2 and Chicago Pnuematic have 1. The sound of the impacts can be heard in the increased frequency of hits as it operates. The last few wrenches I used while working were IRs with dual hammers and composite bodies. Fatal failures were fractured housings usually from drops from heights. They were lighter to handle and provided a real 600 pdft of torque forward as measured with a certified torque wrench and 1300 pdft in reverse. Great impact gun. If I was buying battery powered today I would buy what matches my other tools for ease of charging etc. I would say, when going into battle, choose your weapon carefully. I really think that much like today's cars, most of what you can buy are pretty good stuff and pretty powerful.

Brian

[Murray]

There is a youtube channel that covers this and does quiet a lot of testing, most are rated on I think a 1/2 inch bolt for the battery ones anyway, physics dictates it takes a fairly heafty nose dive as soon as you start going larger. Some of the cheap ones will also produce inconsistant torque which is almost as useful as not a lot of torque. I still do final tightening of things like wheel nuts by hand with the tool carried in the vehicle it gives you a good chance of undoing them on the side of the road when you really need too.

[bad Chad]

Like Ncdan, I have a 12v impact driver too.

But mine is a Harbor Freight and is only 10 years old.  It’s a half inch drive and has never left me high and dry.   Just saying.   Not sure how it would do under super heavy use, but it sure handles lug nuts with ease.

[Mike Tashjian]

I have a Milwaukee M18 1/2 impact gun rated at 1400 ft lbs in reverse and 1000 ft lbs in forward.  I also have  a couple of air guns, one being an Ingersol Rand which has 800 ft lbs in reverse when running 120 lbs of air in a 3/8 min hose. Let me put everyone's mind at ease when I say the Milwaukee gun is the real deal.  It's a bit on the heavy side but when you factor in no hose and total portability it's a keeper.  It has three setting and one is max power but instantly slows down when a lug nut is loosened so it doesn't mess the threads up or spin across the floor.  I have to keep my eye on it as everyone who tries it wants to own one. Not a real bargain unless you own some other tools already, but I can say they are for real. 

[steven c]

 A one man consumer reports. Guys amazing.
https://www.youtube.com/results?search_query=project+farm+impact+driver

[AJ Huff]

Man I have learned a lot from this post. Thanks!!

-AJ

[PeteS]

I had a Harbor Freight air impact wrench for a number of years. It wasn't able to remove wheel lug nuts nor torque them over 100 ft lbs. I used a torque wrench for the final torque spec. Two years ago I got a Harbor Freight 1/2" Earthquake XT. Night and day. Has rusted lug nuts off in seconds. If thats the one you are looking at its a good deal.
Price varies. List is about 159 but I have seen it on sale for as low as $119. The 20% off coupons never apply to Earthquake items in the fine print.

https://www.harborfreight.com/12-in-composite-xtreme-torque-air-impact-wrench-62891.html

Pete