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Geocritter's avatar
Geocritter
Explorer
Sep 29, 2013

Advice regarding my air tool/compressor needs

I’m so impressed with the job that the 3/4" drive air impact wrench did for me on my shock absorber replacement that I’m rethinking my rigs air compressor “needs” (my needs really). For the last 28 years I’ve been spoiled with a 20 gallon 7.6CFM @ 100psi air compressor I purchased new in 1985. Unfortunately, it doesn’t fit in any of my storage bays, even with modifications. I’m thinking of purchasing a smaller 10 gallon 4.6CFM @ 90psi air compressor that does fit. The smaller compressor tops out at 120psi. Now here’s where my question comes in. The 3/4" drive air impact wrench I rented was rated at a max torque of 1,100 ft/lb and was designed to run on 6.6CFM and it did run very well powered by my 20 gallon air compressor. Would the same tool work at full torque for a short time, possibly 15-30 seconds on the 10 gallon air compressor at 120psi? I’m not really searching for speculation, but for input from people who’ve used these tools much more than I have. I realize that I can purchase a heavy duty electric impact wrenches, but the air compressor has some many other uses I’d prefer to go that route if possible. Also, I’ve noticed in my internet search that some of the better 1/2" drive air impact wrenches seem to develop adequate torque to meet my future needs. Any comments would be appreciated.

Thanks in advance for any help y’all can give me sorting this matter out.

Steve
  • Since you have a class A and I presume a Generator look at 110 volt impact wrench. I did try the air impact wrench on a small harbor freight compressor VS a nice OLD Craftsmen. I could not loosen the lug nuts on my tires while hooked up to the small compressor but could with the larger compressor. I did not want to haul that big compressor around so I bought a electric model impact wrench. It loosens 250 ft LB lug nut easily. I did not try higher because I do not need higher. I just carry the small compressor to fill tires and operate my air powered hydraulic jack (oh how I like that piece of equipment).
  • One of my issues is that my RV is also my home. Currently I have a storage space nearby, mainly for family keepsakes and for now, my extra tools. However when I hit the road in a month or two the storage space won't be so convenient, hence my desire to have tools with me that can git-r-done. BTW I purchased a torque multiplier and didn't have much luck with it. I talked to the Snap-on tool man about it (I didn't purchase it from him). He said that they're made more for tightening bolts and not for untightening. I just don't know what to believe. He also offered to loan me an air impact wrench, but like a fool I didn't take him up on it.
    Steve
  • Geocritter,
    Well Sir, as has been stated, a 3/4" gun will deplete your "intended" little compressor almost instantly. I too have had the pleasure of having home air, a Sears 20 Gallon, two horse unit for the first 20 years and the one we have now, a 30 Gallon, 3 horse unit for about 19 years. This 3-horse unit is set for 150 psi cut out. It will handle a 3/4" gun, efficiently for about 10-15 seconds of full trigger pull. After then, it's no more power than a reasonable 1/2" gun.

    Yes, you need MASSIVE volume and, at sustained psi. in order for full value of high torque tools to operate efficiently. I too like air tools and having the ability to use them if and when needed. But, in reality, just how much "big" work are you or I, planning on doing while out on the road? I too do all my own work and, it's very handy to have air tools giving assistance when and where needed but, a couple of things prohibit this.

    1. Like what's been stated, you need high volume and high pressure for just about any of them to be of real value.

    2. And, since the one you're thinking of is not anywhere near what you'd need one for, you'd need a seriously larger one to accommodate the drive needed for those tools, and you say you don't have the storage capacity for such a large unit.

    3. Then, there's the tools themselves. There's lots of weight there and, volume of space needed for, whatever ones you plan on toating with you on your adventures.

    Don't get me wrong here, I commend you for thinking that way. Being as prepared as one could be is always nice. I was thinking along the same lines when preparing for a "just in case" situation with my lug nuts, if ever the need arose for removal. 450 ft.lbs. of torque is fairly tough to deal with out on the road or, even at home most of the time. So, long story short, I was thinking of a 3/4" gun and large volume hose, adapters for small line to big line etc. etc. but, instead, I purchased a Torque Multiplier that is seriously strong enough to break those lug nuts loose, if ever needed.

    So, just some info for you if it's of any value. Take care.
    Scott
  • The smaller unit will never keep up to that big honker, you will be constantly waiting for it to recover. Most compressors will put out 100+psi, you need volume. 1/2"gun will not consume as much air but likely won't have the power you want.