Impact wrench - PeachParts Mercedes-Benz Forum

hs_300e · #1 03-25-2003, 11:05 PM

Do any of you use an electric impact wrench?

What are your thoughts and any feedback is appreciated.

TIA.

#2 03-26-2003, 07:36 AM

I haven't seen an electric impact wrench in years although I'm sure they still make them. Unless they have changed drastically, they are heavy and bulky with limited torque.

There are so many good air impacts of all descriptions economically available these days, I'm not sure why anyone would consider an electric one. If you don't have a compressor, one of the small 110V pancake or contractors compressors would drive a set of air impacts just fine. Where such compressors come up short is for items requiring continuous volumes of air such as paint guns.

If you had one of these compact, inexpensive compressors, you could then collect a complete selection of air tools such as air ratchets, butterfly, 1/2" pistol grip and maybe an air hammer. These are DEFINITELY worthwhile gadgets to have handy.

Good luck,

Potomac Pat · #3 03-26-2003, 08:51 AM

I don't use one, but we have a DeWalt here & it is pretty hefty !!

G-Benz · #4 03-26-2003, 12:48 PM

I would suspect that the biggest issue with electric impact tools is weight!

The electric tool must self-contain whatever mechanism and power supply is needed to drive it effectively...and that's a lot of stuff to heft around!

At least for air tools, the compressor is the power supply and is remotely located...not strapped to the tool!

william rogers · #5 03-26-2003, 09:29 PM

air tools are greatest thing since "talkies" they are inexpensive compared to ele.counterparts and are smaller and safer.I have I have eight different air tools and will add more........
William rogers.........

Southern · #6 03-28-2003, 09:53 PM

I recently have purchased some air tools since I acquired a 60 Gal 7.5 HP air compressor at an estate sale. Air tools are very handy when working on cars and air impact wrenches make taking off lug nuts much faster.

I have to disagree with Larry on one point. A small compressor (with low CFM output) will struggle to break loose a nut torqued to more than 120 Ft lbs. I tried to break loose my harmonic balancer bolt using my neighbors pancake compressor. After 5 sec. of continuous use the air from the tank was depleated and could not supply enough CFM to operate the impact wrench.

Concerning your original question about electric impact wrenches. I believe that the latest trend is cordless electric impact wrenches. I do not have any info on them.

#7 03-29-2003, 05:02 PM

rjohnnie,

Pressure is pressure. You probably didn't have the regulator pressure turned up high enough on the pancake. The only down side to the pancake is that it makes very little volume, but air tools don't need much.

I run my 5HP compressor at no more than 120, you can get 120 out of small portables. I have one that is similar to a pancake with a different shaped tank. It makes 120, no problem.

You may have your 7.5HP monster cranked up to some pressure higher than what a pancake will make. If you do I would not recommend using high pressure unless you really need it for a stubborn bolt. Your air tools will last much longer with lower pressure and run only slightly slower, not enough to notice.

Good luck,

william rogers · #8 03-29-2003, 09:00 PM

-It's also easy to twist the head off small bolts with air set to high most 1/2 inch impact guns have a pressure adjustment on near the air inlet.I perfer to use a tight fitting box end or scoket on stuborn bolts or nuts I apply down pressure and tap the handle with a hammer then when loosened run it out wit an air racthet or impact gun.........
William Rogers.........

Imatation · #9 03-29-2003, 11:15 PM

Most of the major tool companies (I know dewalt and milwauke) make electric impact wrenches, and there are even some cordless ones. I do agree with pretty much everyone else though, a shop definatly is not complete without some type of air compressor. I have a small pancake type compressor made for moulding work, and it works fine for most of the things i can come up with.

BoostnBenz · #10 03-30-2003, 12:53 AM

I've seen and heard of electric wrenches before, not impressed by them though. All seem kind of weak and heavy. If you insist harbor freight sells one with like 250ft/lbs for ~$20.

Quote:

A small compressor (with low CFM output) will struggle to break loose a nut torqued to more than 120 Ft lbs.

Three different things here, size, volume, and pressure. Just because a compressor is big doens't mean it puts out a lot, nor does small mean that either. There are HUGE compressors out there, single staged with little output (CFM). On the other hand some pancake compressors can out pump pretty much any "normal" single stage compressor. I've seen 6+CFM in a pancake before, but I've also seen the worst CFMs (<2 CFM :p) in them before too.

Quote:

It's also easy to twist the head off small bolts with air set to high most 1/2 inch impact guns have a pressure adjustment on near the air inlet.

While this is very true, it seems like the hammering of an impact wrench helps free it up easier. It seems much more common that I snap heads off with breaker bars than with a impact wrench (granted the torque difference, but i think there sometimes is a bad 'moment' put on the head of a bolt with a breaker bar). I guess I've just learned my limits from experience, if the 425ft/lb ingersol rand can't do it, it means either risk a breaker bar or get out the torch.

I really don't favor using the 900+ ft/lb 3/4" drive impact wrench on those stuborn nuts/bolts.

I believe almost all air tools are designed for 90psi max pressure.

#11 03-30-2003, 02:09 PM

Can someone give me an example (brand name, harbor freight number, etc.) of a pancake compressor that would drive air tools.

Thanks,

Southern · #12 03-30-2003, 05:27 PM

Larry,

I agree with you that pressure is pressure but that was the problem with the small pancake compressor. I had the pressure set for the max (110 psi) and when the impact wrench was run continuous the air depleated from the tank causing the pressure to drop below 80 psi. The tiny motor for the compressor was not capable of replenishing the air quick enough. The motor was about the size of the air compressors that you plug into a 12VDC receptical.

I do not have a need to crank up the air pressure for my 6.5HP (correction it is not a 7.5HP) compressor, the compressor switch shuts off at 125 psi. I have three air taps for my compressor. Two are located after the pressure regulator and one located before the pressure regulator. I found a handy device at Menards for my air tools - it is a small oiler which I put quick air connections on it to use as an inline oiler. This way I do not contaminate my air hoses with oil and the air tools gets lubricated as I use them.

The 1/2" air impact wrench that I have requires 4CFM @90psi. In order to size an air compressor you would need to take the air tool which requires the most air consumption (CFM and PSI) and compare this to what the air compressor is capable of delivering. In my case my dual action sander requires the most air (6.5CFM @ 90psi).

Imatation · #13 03-30-2003, 05:32 PM

any pancake compressor will drive air tools, as long as it will go above 90 or so psi. Here are some links:

Dewalts smaller compressors:

http://www.dewalt.com/us/products/tool_detail_listing.asp?categoryID=882

porter-cables small pancake style compressors:

http://www.porter-cable.com/index.asp?e=547&p=2581
http://www.porter-cable.com/index.asp?e=547&p=2582

porter-cable small side tank compressors:

http://www.porter-cable.com/index.asp?e=547&p=2586
http://www.porter-cable.com/index.asp?e=547&p=2585

BoostnBenz · #14 03-30-2003, 08:51 PM

Does anyone know the conversion between CFM & SCFM. I believe SCFM means standard cubic feet minute, but there always seems such a difference between the two different ratings. For instance my compressor is rated at 8 SCFM @ 50psi, yet can't keep up with a 5 CFM die grinder.

Dweller, any air compressor can run air tools, but if the compressor itself can't keep up with the volume of air the impact wrench uses it would deplete the air supply to nothing in a short amount of time.