Air Impact Wrench

Bird · Apr 25, 2002

Would it be as simple as half closing the regulator to get 500 ft pounds?

Not really, it would be very imprecise, for maybe somewhere in the neighborhood./w3tcompact/icons/laugh.gif

We've been through a lot of this in previous discussions I think, but remember that every impact wrench I've known of was rated at 90 psi air pressure. The power will be less if you have less air pressure, and it'll be more if you run higher air pressure. A lot of mechanics have two stage compressors with about 175 psi, so their air tools are much more powerful, and they break or wear out more frequently which sure helped my business./w3tcompact/icons/laugh.gif The manual may also say something about "ultimate" torque, which means if you hold the trigger until the bolt just won't turn anymore, but a lot of ratings are for a 5 second burst of air; i.e., the torque after holding the trigger for 5 seconds (you can even buy a regulator that allows 5 seconds of air and cuts it off - used on assembly lines mostly).

Oops, gotta go. I'll try to answer more later.

MikePA · Apr 25, 2002

BTW, these compressors are a lot like our tractors....
I was afraid someone would say this! /w3tcompact/icons/laugh.gif

I was looking for an inexpensive compressor that would run an impact wrench for use on the mower deck and other tools for maintaining the tractor. These are my 'inexperienced' requirements;

- Portable (wheeled - see third requirement)
- Vertical (less floor space)
- 110 volt (no 220 where it will be kept plus it would also allow me to take it to other locations and find power easier)

Jeff396 · Apr 25, 2002

Can't help you with that. I have never owned or used a 110v air compressor. However, with the exception of my sand blaster I have a guage where I turn down the pressure to that indicated in the manual for each tool. I think my impact specified 90 psi maximum. I would think you wouldn't have any problem checking the rating on a particular compressor against the different impact guns. They don't use any where near the air volume as my blaster.

Jeff

gordon · Apr 25, 2002

As usual Bird has it correct. First don't ever trust the setting on any air tool for even close to precise torque values. Ballpark at best and I mean for not only impact guns but air ratchets as well. The only safe way to measure torque is a torque wrench, if your trying to get closer than a ballpark measurement.

Also if your going to invest in air tools, protect your investment and oil your tools after each use! This can't be under stated. To also help on the life of the tool use a pressure regulator and a water/oil separator before the tool. Sharpe makes some nice simple setups.

As Bird said most air tools are rated for 90 psi some are rated for less. So that is the reason for the regulator. It will save the seals of the impact gun, ratchet, shear, grinder, drill, buffer, hammer, sander or what ever your using./w3tcompact/icons/smile.gif

Gordon

Knight9 · Apr 25, 2002

Mike,

My compressor meets all of your requirements. It is a Husky from Home Depot. Vertical compressor with wheels. Not oil-less. It is a fairly heavy unit on wheels with a nice handle for wheeling it around. I've only used it for tires and some air blowing so far, but an impact wrench is planned for later in the spring /w3tcompact/icons/wink.gif/w3tcompact/icons/smile.gif. It was a reasonable price.

Kevin

Bird · Apr 25, 2002

Mike, the other thing to consider is how often you will use the compressor and how long it will run when you use it. I have, in the past, recommended against the oilless (or oil free) compressors because they have a life span of about one-tenth that of a compressor with a crankcase and oil, but if you're only going to use it briefly or occasionally to air up tires, use an impact wrench, etc., they may be good enough for your use. If, on the other hand, you want to use a sandblaster, forget the oilless; you'll burn it up before you get the first job done. [/b]However[/b], the good news is that you can completely rebuild it in less than an hour with $40 to $60 worth of parts.

And, yes, they're like the tractors; just depends on what you like and how you intend to use it. Most "professional" mechanics wouldn't even consider a Campbell-Hausfeld product (throw away tools - when it doesn't work right, throw it away and buy another one 'cause it'll cost more to fix it than it's worth). Well, I agree; never saw a broken one that I could buy parts for and fix for less than it was worth. However, properly cared for (which is nothing more than keeping it clean and lubricated), they'll probably last a homeowner 20 years, so they could very well be the best value for you.

And like the tractors, try to think of every tool you might want to use with a compressor (impact wrench, air ratchets maybe, air up tires, use a blow gun to clean things - those are the obvious, but how about paint gun, sandblaster, hammer/chisel, drills, sanders, saws, etc.?). You're highly unlikely to ever need more than 90 psi, but look at the volume ("cfm" or "scfm") required for each tool, and buy a compressor rated for that volume. I'm like Jeff; the sandblaster requires the most. And I don't "sweep" the floor in my shop with a broom; I use a long stemmed air gun to "blow" everything out the door; sometimes takes awhile and the compressor may run quite awhile. Look at the compressor specs; does it warn you against running it more than a certain length of time - probably 10 minutes.

I've owned Campbell-Hausfeld, Sanborn, DeVibiss, Craftsman (made by DeVilbiss), and Puma compressors; none of them are bad if you get the model rated for the jobs you want to do. And of course, I've spent a bit of time in the business of repairing/rebuilding air tools. I've got some Ingersoll-Rand (my personal favorite for impacts at least) tools, but I've also got some cheap Harbor Freight "Central Pneumatic" tools that I've used for years.

On the impact wrenches, be sure to read the specs (example: the Chicago Pneumatic CP734 is rated at 425 ft/lbs and is quite possibly the most frequently "cloned" half inch impact there is, but most of the clones are rated for 250 ft./lbs.), then buy cheap is probably your best bet.

And this is getting too lengthy. If you run into any specific questions, e-mail me and I'll try to help you.

MikePA · Apr 25, 2002

Bird, Thanks so much for your informative reply. I will ponder my potential uses. It seems that the 110v models top out between 5.5 to 6.0 cfm at 90 psi. Higher means 220 which means loss of portability.

Did you use a torque wrench on your mower deck blades when re-installing them?

Bird · Apr 25, 2002

I have an Ingersol Rand IR2131 which is their top of the line 1/2 inch model

Ain't that a blast, Jeff?/w3tcompact/icons/laugh.gif The first time I saw one was when I got one in to repair, I thought a plastic impact wrench - no way./w3tcompact/icons/shocked.gif Of course they call it "composite" instead of plastic./w3tcompact/icons/laugh.gif Well, I learned a few things, and repaired a bunch of them (all due to severe abuse such as dropping them in mud puddles, using 175 psi, letting the car lift down on them, and little things like that); (1) it's their top of the line, most powerful, as you said (popular with diesel mechanics), (2) it's less susceptible to moisture damage than most, (3) it's the easiest one to disassemble and assemble (after you learn how - the manual on that topic has one serious error), and (4) parts are cheaper than for many others. A great tool! And did you know that Matco, Craftsman (and I don't know who all else) have their own versions - different model numbers, different colors, but the same tool made for them by Ingersoll-Rand?

MikePA · Apr 25, 2002

Is this the one you're talking about? $210 at Harbor Freight.

Bird · Apr 25, 2002

It seems that the 110v models top out between 5.5 to 6.0 cfm at 90 psi.

That's about right, and that's usually enough, except for sandblasters, some of the sanders, and really big paint rigs. And you can use small sandblasters if you don't mind stopping to give it time to catch up every few minutes, and if it won't hurt the compressor to run almost continuously.

Dis you use a torque wrench on your mower deck blades when re-installing them?

Nope, it's recommended and I even agree with the recommendation, but for me personally, I just use my IR231 impact wrench./w3tcompact/icons/laugh.gif