Why Do I Need 1000+ ft lbs in an Impact?

[zkling]

This is worth repeating. It's hard to get people to understand that when manufacturers say 90PSI max air pressure they mean set the air regulator to 90 with the tool at full throttle free speed. Most people think it means just set the regulator to 90 at rest. Then wonder why the impact has no balls.

I don't think that is what Marlin is saying. What you are referring is static pressure vs dynamics pressure. I don't think you are going to notice that much of a difference in ~5-10psi. At least not the difference between nut come off and nut no come off.

From IR themselves

http://www.ingersollrandproducts.co...es/impact-gun-torque-ratings-science-or-magic

 

[Marlin]

Well it's nice that IR isn't bashful about stating "Made in China" on most of their new stuff.

IR does adhere to the letter of the law, so for the premium line of impacts when it says that it is "Assembled in USA" you can be sure that a "significant transformation" occurred in the US per the FTC rules for labeling assembled in USA.

 

[Marlin]

I don't think that is what Marlin is saying. What you are referring is static pressure vs dynamics pressure. I don't think you are going to notice that much of a difference in ~5-10psi. At least not the difference between nut come off and nut no come off.

From IR themselves

http://www.ingersollrandproducts.co...es/impact-gun-torque-ratings-science-or-magic

We actually measure the pressure at the inlet of the tool after any quick connects with the tool free speeding, so the tool is not seeing any pressure drops caused by the hose or fittings.

 

[zkling]

We actually measure the pressure at the inlet of the tool after any quick connects with the tool free speeding, so the tool is not seeing any pressure drops caused by the hose or fittings.

Just to make sure I understand the terminology. When you say "free speeding" you are talking about just holding the trigger of the gun at full throttle with no load on the drive end?

 

[Marlin]

Just to make sure I understand the terminology. When you say "free speeding" you are talking about just holding the trigger of the gun at full throttle with no load on the drive end?

Correct.

 

[sberry]

Almost any impact will work for this man. He wont use it 6 months in a lifetime. Auto parts stores sale flyers have brand name impacts on sale all the time, brand stuff in HF catalog and Northern. I bet you can buy a decent China gun at Home Depot for 80$ that work pretty well.

I ran in to a set of dipshit installed lugs last week, had to get on hi air to get them off.

 

[zkling]

Correct.

Can you define "Average air consumption" vs "Air consumption at load" and how you determine those please?

Almost any impact will work for this man.

Kinda what I was thinking as well. How about the HF earthquake or a used (USA) 231? Each should be well under $100. Heck I use a POS china made CH gun that I paid $10 for on clearance at lowes. Actually it was a kit for $20 and came with a 3/8" air ratchet as well .

Only time it has let me down was trying to remove a notorious Honda crank pulley bolt. Then again, I'm just a weekend DIY guy that has a tendency to work on rusted junk quite often.

 

[CWP1616L]

I'm pretty sure an old school IR 231 (425 ft-lbs) would take anything off that's on a passenger car. I've used those things and they're a beast.

 

[TwoInch]

average air consumption is the ******** rating they use to make tools appear more compatible with homeowner grade compressors.

"average consumption" on most 1/2 impacts are generally around 5cfm, but the impacts actually use about 27-30cfm in normal use.

the explanation is that the tool is only used for a small percentage of an amount of time. lets say 15 seconds out of every minute(example), and at 50% or 75% max output(example). its a useless rating and just clouds the already ridiculously confusing information available from compressor and air tool companies. none of the consumption and output number systems are directly comparable, but they make them appear is if they are.

 

[redwrench60]

Hmm. I absolutely did NOT know this. I thought you just set the reg to 90 with the tool off.

Why did I grow up so ignorant. I'm 37, shouldn't I know all this ****?!

Yeah, that little nugget was regretfully omitted from our copy of the book of man knowledge our fathers gave us along with our first razors.

And yes, you will notice a big difference in performance if you feed an air tool properly. Air tools gobble huge amounts of air volume and most home setups can't keep up.

 

[zkling]

average air consumption is the ******** rating they use to make tools appear more compatible with homeowner grade compressors.

Hence I would like to hear the definition from Marlin, since he is an engineer at IR. See what he says is the proper use of the specs they provide.

 

[crewchief888]

if you arent looking to spend $200 on an impact,

IR 231 can be gotten for under $150.
ordered my last one from summit racing, $137 delivered to my front door.

i've been using them for years working on const eq.

if i need more power, i go to 3/4" dr, or long 3/4"dr ratchet and torque multiplier.

 

[sberry]

chief,,, I figured you could get a good gun for 150. Prices have stayed steady. I bought my last heavy CP for under 2 off the shelf. 727 or 747, don't remember but I like it, got a 4 speed

 

[Kev442]

Bull,

I think the most important thing to come out of 5 pages is that if you don't have the compressor or airlines, you are never going to see 1000 lbs at the gun anyway. After I got those things right, I remove lugnuts at 2 out of 5 on my gun's settings.
Frankly, my experience with the rust belt on passenger cars is that it's going to come loose or simply snap at less than 500 lbs. I don't own or work on a Honda, so no worries there.

 

[crewchief888]

chief,,, I figured you could get a good gun for 150. Prices have stayed steady. I bought my last heavy CP for under 2 off the shelf. 727 or 747, don't remember but I like it, got a 4 speed

i agree. couple of IR 231's i bought off the snapon truck for $150-$165, one from sears at $155,
this time around, even with "processing" charges summit was still the cheapest, and it was at the door within 36 hours of me ordering it.

i get 8-10 years out of a 231 before they are just beat to hell, worn vanes, rusty bearings, and beat up and broken anvils.

 

[redwrench60]

IR 231. Perfect for the homeowner and the budget minded pro. Classic looks, good power, reliable and priced right. Or a good used IR 2135 ti max. They show up at pawn shops near me in the $60-$150 range.

 

[TwoInch]

Hence I would like to hear the definition from Marlin, since he is an engineer at IR. See what he says is the proper use of the specs they provide.

some of the worst misinformation i have heard has come from people that are "professionals" in the air tool business. the waters are so muddied, that even a lot of the guys that know whats up, dont know whats up.

not saying marlin has or will share bad info, just stating my experiences.

 

[CWP1616L]

if you arent looking to spend $200 on an impact, IR 231 can be gotten for under $150.

IR 231. Perfect for the homeowner and the budget minded pro. Classic looks, good power, reliable and priced right. Or a good used IR 2135 ti max. They show up at pawn shops near me in the $60-$150 range.

Yes, but I recommended it first, so if he buys it, I win the contest.

 

[Bull]

But after telling me you can never have too much power, now the idea is that I can get by with any old gun?

 

[redwrench60]

Yes, but I recommended it first, so if he buys it, I win the contest.

Lol, yup you'll collect the bird dog fee this time.

 

[KinzeMech]

Ever work on Farm equipment?
I've got a bush hog that the Nuts are torqued to 650 ft-lbs, add a little rust and some time. 1000ft-lbs might work.
Wedge

Every day.
I had some blade bolt nuts that just would not let go one day. I pulled my service truck into the shop, fired up the compressor, held the unloader pilot down until the tanks pumped up to 210 (popoff lets go at 215, standard cutoff is about 175), got my 3/4" impact with 1/2" air hose and 1/2" couplers, and let it have it.

It's amazing how much you can wake up a gun with more pressure and more volume.

Every time your impact saves you from having to resort to the hot wrench, it has saved you at least 15 minutes.

 

[redwrench60]

But after telling me you can never have too much power, now the idea is that I can get by with any old gun?

Yeah, but you busted us back to private when we tried to involve you in our plans for Snap-Rand world **********.

 

[KinzeMech]

1000lbs would require some high quality sockets. Can you imagine an HF socket at 1000lbs of torque?

I don't have to imagine it. They handle it remarkably well. I have tried my best, but not broken one yet.

 

[Bull]

Do blows per minute or free speed ratings affect bolt-busting potential?

 

[TwoInch]

Do blows per minute or free speed ratings affect bolt-busting potential?

nope, only the speed at which they will bust said bolts free.

 

[zkling]

Do blows per minute or free speed ratings affect bolt-busting potential?

Not really, just speed. Free speed should be how fast it can un thread the fastener after it is broken loose. Blows per minute, the more BPM the faster it should break the fastener loose.

Anxious to see what the IR engineer has to say.

 

[thebeekeeper1]

1000lbs would require some high quality sockets. Can you imagine an HF socket at 1000lbs of torque?

Not since last Saturday. They did fine on an antique tractor wheel disassembly.

 

[thebeekeeper1]

Hmm. I absolutely did NOT know this. I thought you just set the reg to 90 with the tool off.

Why did I grow up so ignorant. I'm 37, shouldn't I know all this ****?!

Believe me guys, I'd love to buy one of those IR2135 guns, but I can't justify the cost of that, or a Snappy or whatever else in that range. I can buy an NOS USA-made Sioux for about $150 shipped. I can't find much at all on the net about the gun but found one place that rated it at 600 or so ft. lbs. I have no idea what scale (breakaway or whatever) that refers to. Or, I can buy an Aircat/Nitrocat for around the same money that supposedly puts out 1000+ torque numbers. That's it.

You can't waste your time reaching for the stars when your arms are stumpy.

I got my I-R 2135 tiMax at a pawn shop--for $119. It was new, but no box/papers. If you aren't in a hurry you might try finding a used one. I looked for over a year before I stumbled across it.

Same shop, shortly after, I got a Fein Multimaster for $139--the one that sells for $400+ normally--also new.

 

[nissan_crawler]

One thing if you get one, replace all your fittings with Milton type V high flow fittings. It makes a huge difference on my impact, 3"'cutoff wheel, etc.

 

[Marlin]

Can you define "Average air consumption" vs "Air consumption at load" and how you determine those please?

Average air consumption is value based on expected or average run time of a tool to gauge whether you can expect to run the tool on a given compressor. An impact has two flow ratings, one at free speed and one at load, which is typically measured with the tool running on a brake adjusted to 9 rpm. Niether of these are really meaningful when trying to understand if your tool will run on your compressor because impacts are not typically run in these conditions for long periods of time. So while the at load flow of an impact might be 23 scfm, you do not need a compressor with that flow rating for normal use of the tool. A grinder or sander would be different, as the run times are typically longer, as is reflected in their average air consumption values.

 

[ndoran]

I know I had a big impact (pun intended) on the performance of my impact when I installed an auxillary tank in parallel with the compressor tank and joined the outputs of the two tanks into a manifold that feeds the 0.5 inch diameter airlines I use. Even my old bluepoint AT555 has not failed to remove anything. When you press the trigger the two tanks provide that initial large volume of high pressure air you need to kick the gun

 

[KinzeMech]

If the load flow of a tool is 23scfm, then listing it with an average scfm requirement of "5" is useless information. That figure is arrived at with an assumed duty cycle, and that assumed figure is rarely published. Incorporating an assumed figure into an equation makes the entire result useless.

If I need a compressor for my shop, and I know I have 4 guys running 4 guns at up to a 50% duty cycle, the only thing I need left to calculate air demand is the actual amount of air the gun uses, while the trigger is held on. Leave it to the end users to calculate their duty cycles and determine flow requirements, as that figure varies widely.

I will give props to IR on this issue. I do believe I have been able to find load flow listed on their website. Most manufacturers do not disclose this. It is usually 4x-5x the listed average SCFM, meaning typically a 20%-25% is what is assumed when calculating the average.

 

[Delray]

First model HF Earthquake and an older cheap HF 3/4" have been working well for me.

If I could afford better I would probably go with a SO or IR titanium based on what I've seen.

By the way the ******* on my Milton connectors are slightly less than 1/4" and my compressor is rated at 14cfm @ 155psi. I'm not an engineer but being my compressor cannot maintain 155psi with some high volume tools I think I can assume my lines are capable of a 14cfm flow at the least.

 

[KinzeMech]

It's not that simple.

How much of a pressure drop exists at that rate of flow? Does it do one much good to have 30 cfm of flow if there is a 60 psi pressure drop across that junction?
It's not enough to just get flow through the junction, you have to retain pressure as well.

 

[TwoInch]

Average air consumption is value based on expected or average run time of a tool to gauge whether you can expect to run the tool on a given compressor. An impact has two flow ratings, one at free speed and one at load, which is typically measured with the tool running on a brake adjusted to 9 rpm. Niether of these are really meaningful when trying to understand if your tool will run on your compressor because impacts are not typically run in these conditions for long periods of time. So while the at load flow of an impact might be 23 scfm, you do not need a compressor with that flow rating for normal use of the tool. A grinder or sander would be different, as the run times are typically longer, as is reflected in their average air consumption values.

good info. but i disagree about the actual flow being non-meaningful. the average is useless, and in my eyes, much less useful than the actual air consumption of the tool. once you have the actual air consumption, its much easier for the end user(me) to decide if my setup will be adequate in my usage patterns. IR does not know if i am changing tires all day, or doing suspension work mostly, or assembly. all would have a vastly different ratio of on/off time.

if air tool companies would drop the "average consumption" ******** ratings that are simply an attempt to make tools appear "compatible" it would be much more straightforward when deciding on compressors and tools.

that my .02, but i bet people with a decent understanding of how this stuff works would agree(vast majority do not understand, hence the issue)

 

[TwoInch]

By the way the ******* on my Milton connectors are slightly less than 1/4" and my compressor is rated at 14cfm @ 155psi. I'm not an engineer but being my compressor cannot maintain 155psi with some high volume tools I think I can assume my lines are capable of a 14cfm flow at the least.

you are trying to compare compressor ratings with flow at pressure. you cant do that directly. that 14SCFM@155psi is a measure at the intake of uncompressed, atmospheric pressure air. has nothing to do with pressurized air coming out of the regulator, or flow through orifaces at pressure.

your lines are capable of much more that 14cfm at 155psi, by the way. but to figure out what it actually will flow, we need to air line I.D. and length. a simple .25" orifice or hole will flow about 150cfm to atmosphere at 155psi, with no hose. add lengths of hose and it drops drastically.

i have heard guys claim that their compressor will over run their safety pop off valve. which is completely untrue and impossible with a functioning safety valve. they flow a ton of air, many times what any compressor in any of our shops will make.

 

[Marlin]

good info. but i disagree about the actual flow being non-meaningful. the average is useless, and in my eyes, much less useful than the actual air consumption of the tool. once you have the actual air consumption, its much easier for the end user(me) to decide if my setup will be adequate in my usage patterns. IR does not know if i am changing tires all day, or doing suspension work mostly, or assembly. all would have a vastly different ratio of on/off time.

if air tool companies would drop the "average consumption" ******** ratings that are simply an attempt to make tools appear "compatible" it would be much more straightforward when deciding on compressors and tools.

that my .02, but i bet people with a decent understanding of how this stuff works would agree(vast majority do not understand, hence the issue)

In most cases we try provide both. If we only provided the at load number there would be a lot of people that would feel that their 5 hp compressor would not run their impact.

 

[Delray]

you are trying to compare compressor ratings with flow at pressure. you cant do that directly. that 14SCFM@155psi is a measure at the intake of uncompressed, atmospheric pressure air. has nothing to do with pressurized air coming out of the regulator, or flow through orifaces at pressure.

your lines are capable of much more that 14cfm at 155psi, by the way. but to figure out what it actually will flow, we need to air line I.D. and length. a simple .25" orifice or hole will flow about 150cfm to atmosphere at 155psi, with no hose. add lengths of hose and it drops drastically.

i have heard guys claim that their compressor will over run their safety pop off valve. which is completely untrue and impossible with a functioning safety valve. they flow a ton of air, many times what any compressor in any of our shops will make.

So are the ratings simply pump displacement times rpm? I always thought the ratings were of supplied air at listed pressure but at the displacement of uncompressed AP air.

 

[Rico.]

In most cases we try provide both. If we only provided the at load number there would be a lot of people that would feel that their 5 hp compressor would not run their impact.

Well then that would be the fault of the stupid people for not reading the information.


I'm not talking to you directly Marlin, but I am so sick of manufacturers and distributors
marketing goods and equipment to the lowest common denominator idiot morons with
information that benifits neither them or normal people who take the time to understand
how things work and how to do a simple calculation.

When it comes to air tools all we really need to know is full load cfm and minimum psi
to run it. Thats it. how can any manufacturer "assume" a duty cycle... Me in my little
DIY garage taking off one wheel and two suspension bolts is going to be slightly
different than a pro dissasembling a car for 8 hours and the information given to us by
air tool companies is next to usless for both of us. But at least the Dumb **** idiot
down the road will be happy because he thinks his 1.5hp POS will run the new impact
wrench he just bought.

Anyway... rant over... We now return you to regular scheduled thread.....

 

[TwoInch]

So are the ratings simply pump displacement times rpm? I always thought the ratings were of supplied air at listed pressure but at the displacement of uncompressed AP air.

displacement, but also the efficiency of the pump. for instance, i am sure you notice that there are generally two or more ratings on a compressor, usually xSCFM@40psi and xSCFM@90psi. the reason for those two different measures, and the reason why the 90psi rating is always lower than the 40psi rating is because there is always a small amount of air left between the head/valves and piston. as the PSI in the tank increases, the air that is left in that piston/head clearance space will expand back into the cylinder as the piston goes down for another gulp of air through the intake, thus allowing less air into the cylinder for the next stroke. the pump becomes less and less efficient as the PSI increases.

so in short, no its not a rating of supplied air out of the tank. it only use AS IS is for compressor comparisons. not at all for air tool selection.