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air impact wrench question

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  • air impact wrench question

    Hello, I'm new. Got some good info from this forum. Got a quick question. I live on a farm, plus i'm a registered nurse. have a bunch of farm machinery at home. I purchased a VT6271 air compressor for the garage. Reason why I purchased it: it's mobile and borderline between professional and at home air compressor. Basically, I'm going use it to remove nuts off of machinery and maybe an occasional paint spraying job around the house. no auto work.

    Specs on the Vt6271 are:
    3 Running HP, 26 Gallon Cast Iron Compressor powers a variety of air tools for the serious do-it-yourselfer, professional, or contractor. Product life up to 5,000 hours. Durable and safe ASME code tank for greater storage.
    CFM @40 PSI = 11.5
    CFM @90 PSI = 10.2
    Max Pressure = 135
    Pump type cast iron

    I know it's not the most fanciest air compressor out there. I was thinking about getting a 3/4 in impact wrench. Was thinking the Chicago Pneumatic Air Impact Wrench — 3/4in. Drive, Model# CP772H. Specs are

    Drive (in.) 3/4
    Average Air Consumption (CFM)6
    CFM at Load 24
    Speed - No Load (RPM) 4200
    Blows Per Minute (BPM) 900
    Max. Torque (ft.-lbs.) 1000
    Working Torque (ft.-lb.) 100-700
    Inlet Size (in.) 3/8
    Min. Hose Size (in.)1/2
    Hammer Mechanism dynapact clutch
    Standard Bolt Capacity (in.) 1
    Variable Speed yes

    Will this wrench work on this compressor? CFM at load confuses me. Will this compressor be sufficient enough to support this impact wrench? Any advice would be greatly appreciated.

    Last edited by Redonmyhead; 11-30-2009, 02:17 PM.

  • #2
    Re: air impact wrench question

    yes it should run it,

    no it would not run it continuously, but the way an impact wrench works is you normally use it in short bursts, and since you have a reasonable sized tank, you will have enough to run it for 30 to 45 seconds and then you may need to let the compressor catch up, on a big truck lug nuts, that is taking all the wrench can do, you may have to let it build up and work on a lug nut and then if it loosens let it build back up and go on to the next one or keep working on the one that is fighting you,

    If you look at the specs you posted on the wrench it takes 24 CFM to run it, but do to the moving from and to different lug nuts or bolts, and the on off use it averages at 6 CFM,

    get a proper sized hose you would do your self a favor if you went with 1/2" hose for that gun, the effectiveness will be much better, you may want to by pass the air regulator if it has one on the tank and plumb in in front of the regulator for the impact wrench,

    I use my 3/4" and even my 1" impacts, but I use my 1/2" most, I would guess I use my 1/2" 90% of the time, my 3/4" 6% and the 1" about 4% of the time.
    on most cars and pickups the 1/2" is more than enough, and the number of times, I need the 3/4 over the years is just a hand full, and the one inch, but when you need them you need them or a long cheater bar.
    (I use my 3/8" much more than the large units),

    I am not saying do not get the 3/4" unit but you may want to try out a good 1/2" and see how good it does for you first,

    I have up to 1 1/2 ton trucks, a few one ton, I there are a number of other cars and ligher pickups, and tractors, and other, (many times I may have both the 1/2" and the 3/4" (such as working on the tractor, and loosen them with the 3/4" and then switch to the 1/2" to finish removing, (the weight is a lot to maneuver around, and you drag that 1/2 hose around for some time, and the lighter 1/2' starts looking nice).
    Push sticks/blocks Save Fingers
    "The true measure of a man is how he treats someone who can do him absolutely no good."
    attributed to Samuel Johnson
    PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and the current state of the economy............the light at the end of the tunnel, has been turned off.


    • #3
      Re: air impact wrench question

      thanks for the awesome reply BHD. appreciate it.

      I think I'm leaning towards the 1/2in wrench 1st. I thought about buying the 3/4in impact wrench and then getting a 3/4in female / 1/2in male adapter to accomadate my 1/2 sockets to save money. I assuming the adapter would not be a wise choise, probably hard on the impact wrench and the adapter probably won't last long? probably smarter to invest on a 1/2in and 3/4in wrench. can never have too many air wrenches around the house.

      I'll be using it mostly on our farm trucks and tractors. Yearly, I work on our 6 head disc mower. biggest nut on it is 1 1/4in. it's a pain in the butt to work with a socket set. figure the impact would save me time and some bloody knuckles. so many nuts on that dang mower to get to the grease reservior and to replace the mower blades. Also, we have tons of flats on our farm due to honey locusts (thorn trees.)

      how big is your compressor? I imagine it's pretty big since you have a 1in impact gun. My mechanic knowledge is pretty shameful. Of course, I grew up in the city and my wife moved me to the country side. Her father has 1800 acres of land. He's about 80 years old and now I'm the sole caretaker of the land. My mechanic skills are slowly growing. Just wish I knew more.

      Thanks again for the info. appreciate it!

      Last edited by Redonmyhead; 11-30-2009, 11:07 PM.


      • #4
        Re: air impact wrench question

        Ingersoll-Rand can't be beat!

        I've got an older version and there's nothing it won't take off!


        • #5
          Re: air impact wrench question

          For years all I had was a small portable air compressor about a 2 hp unit, and use the 1/2" a and the 3/4" wrench, and in the past few years I built up a 5hp three phase motor, on a 80 gallon tank, with a two stage head, and pipe the metal shop for air, one of the nicest Item I got was a air hose reel,
          I got mine from harbor freight, cost about $40 with 50 foot of hose, (not the greatest hose, but its nearly 5 years old I am guessing now and still working well).
          I got the 1" wrench a few years ago, when my son got a small semi truck for his scrap Iron business, and for working on the old fork lift he/we bought for the scrap iron work. (he is currently driving truck),

          on the tires you may consider for the slow off road work tires from "Gensco"
 I would suggest the bolt together rims as well, the side walls on the ones I got have side walls nearly 3/4" thick and the tread area about 1 1/4" thick, they can not dissipate the heat so not for highway use, yes they are rated for up to 200 mph if that is less than 2 miles, and you will not have to worry about over loading them as the weight capacity is amazing,

          I put a set on the pasture pickup, nearly 10 years ago now, (I have had the vale stems rot off), but no flats as of yet, when using car or truck tires on the pickup I many times would fix a tire ever time I would drive in the pasture, one day I had four flats on it,
          I know the locust trees would make them work hard but they would help a lot, there stop leak fluid is good as well.

          One other thing I found (used on the lawn tractor where I mow under some locust trees), is a liner, from Gemplers they work to an extent, but I have found the recycled aircraft tires the best, and they will most likely out last you,

          as far as using adapters I do that a lot,

          I have a very good set of 1/2 impact sockets, there Proto,
          but my 3/4" sockets are impact import, and my 1" are as well, and have served me well,
          (I do have adapters that allow me to use the 3/4" with 1/2" and vice versa, and even the 3/4" to 1" and vice versa,

          some times you may run into a smaller nut that is smaller than the 3/4 sockets and you need that little extra so you use an adapter, I did that with the changing of the tires around on the farm tractors this summer, a few of the nuts on the adjustable rim were more than the 1/2 could handle,

          on that 1 1/4" bolt if it is tighten correctly you will probably need a 3/4" drive to handle it.

          I strongly suggest the use of Impact sockets with an impact wrench,
          many places will not warranty a regular socket if it has been used with a impact wrench, and yes one can tell if it has been used with one,


          one more thing some of the larger impacts have different type of retainers for the sockets (mine use a rubber pin and ring), where the 1/2" at one time had a spring ring on the tip of the drive,
          Last edited by BHD; 12-01-2009, 08:32 AM.
          Push sticks/blocks Save Fingers
          "The true measure of a man is how he treats someone who can do him absolutely no good."
          attributed to Samuel Johnson
          PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and the current state of the economy............the light at the end of the tunnel, has been turned off.


          • #6
            Re: air impact wrench question

            thanks again for the info.

            Newman, funny, I was checking out that wrench. That puppy has some power. pay what you get. was also looking at the IR 2100G from

            BHD thanks for the info. I'll have to check those tires out from Gensco. very interesting after checking their website out. That would be a life saver for us. Been constantly spraying and irradicating those honey locusts but they tend to populate some where else. Father-in-law never really controlled those trees and now there are adult trees everywhere. Cows love eat those pods and then crap the beans out everywhere. oh well, just keep killing the adult trees until they're all dead.

            would love to get a bigger compressor. but eventually we will be moving into her parent's house and i would hate to tear apart an elborate setup and start over again. so the portable is fine for now. Thanks again for the info.