sberry
Banned
Sure.
CFM doesn't really matter with a impact gun,Right?
- Thread starter Nealcrenshaw
- Start date
Sure.
theoldwizard1
Well-known member
An impact wrench is the best example of "getting by". Air chisel/hammer is second. That is pretty much it. Most other tools require air flow for more than 30 seconds.
My 2 hp oil-lubed 240V compressor can not keep up with my HF cut off wheel for more than about 60-120 seconds.
theoldwizard1
Well-known member
So what is the outlet size of your little compressor ? If you really are going ahead with this plan, get an auxiliary tank (the bigger the better) with a 1/4" inlet and a 3/8" outlet.
bcradio
Well-known member
No, you will want to set your regulator at whatever will give you 90psi while the gun is running. This setting will change based on what hose you have connected as well as the different fittings connected in your system.
If you set your regulator to max, you risk damaging or shortening the life of your gun.
dave89iroc
Well-known member
At my old shop we ran everything on 175psi , quality tools lasted forever
ez-duzit
Well-known member
Good post.
A small inexpensive compressor may have a small pressure regulator which will never flow (deliver) 30 cfm at 90 psi. One might be better off to connect before the regulator and set the maximum pressure of the tank to say 100 psi.
Alternately, feed the compressor output to a spare air tank made form a 20 lb propane tank for extra reserve. Keep all the hoses as short as convenient.
<style type="text/css">p { margin-bottom: 0.1in; line-height: 120%; }</style> Notice that all the nail guns have an air reservoir in the handle, enough for the shot.
Alternately, feed the compressor output to a spare air tank made form a 20 lb propane tank for extra reserve. Keep all the hoses as short as convenient.
<style type="text/css">p { margin-bottom: 0.1in; line-height: 120%; }</style> Notice that all the nail guns have an air reservoir in the handle, enough for the shot.
shampoop
Well-known member
That might be true, but I bet no auto shops have regulators on every single air line in their shop and made sure it's adjusted to exactly 90psi working pressure and adjust it every time they get new guns.
I'd be willing to bet most all just make sure it's damned high enough, sounds like it's a common thing and the guns have no problem handling it to me. Most air impacts last a VERY long time in a professional use setting being used all day every day. In a home shop setting where they're used 100X less frequently, possibly shortening the life isn't a big deal. And most peoples compressors only max at like 120-130psi anyway.
sberry
Banned
We tested most of this type of thing. Changing out a hose from 50ft on a reel to 15 thru a good connector delivered +10# to the tool, huge improvement. On a low pressure comp this would be a huge boost.
On a 100 ft circuit changing the main from 1/2 to 3/4 pipe would net less than .2# difference.
On a 100 ft circuit changing the main from 1/2 to 3/4 pipe would net less than .2# difference.
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in the morning im gonna try it again with a higher psi, but so far:
my 4cfm @ 90 psi, Husky 8 Gal Portable Electric Air Compressor, 125psi max,
which i equipped with 50' long, 1/2 inch thick hose with 3/8 inch fittings,
can't even properly power my 3/4" central Pneumatic Earth Quake air impact wrench. (1400 ft lb. torque) I was thinking i could do work with it because "CFM doesn't really matter with an impact gun, Right?" I say wrong. Running a gun that big on an ac that small is gonna overwork your ac, too, b/c it is refilling every 10 seconds (if that) of gun use. The gun sounds starved for air. (I am returning it for an AirCat/NitroCat 1250k because it requires less CFM and has same foot pounds torque.)
It can't even remove the hub nut off this 95 honda civic i play with. (neither can my generic 1/2" air impact wrench rated at 750 ft lb. torque., 4CFM at 90 psi: so a bigger than 1/2" air impact wrench is justified to me)
I noticed a decent jump in power on my 1/2" impact when i went up to a 1/2" hose, but i just want something that will remove my hub nut, and any future nut. Some here say a shorter hose would make a big difference, maybe i will try that, too.
Getting ticked off thinking about having to purchase a bigger compressor... Unless i am able to remove the hub nut with a shorter hose and more psi... Learned a lesson about buying an ac:
Buy the biggest compressor you can get that still uses 120V (which will probably only be 6 or 7 cfm) unless you plan on never changing an axle. (I'm too small and weak for hand tools. I tried heating it.)
CFM is like the ONLY thing that matters on an ac.
my 4cfm @ 90 psi, Husky 8 Gal Portable Electric Air Compressor, 125psi max,
which i equipped with 50' long, 1/2 inch thick hose with 3/8 inch fittings,
can't even properly power my 3/4" central Pneumatic Earth Quake air impact wrench. (1400 ft lb. torque) I was thinking i could do work with it because "CFM doesn't really matter with an impact gun, Right?" I say wrong. Running a gun that big on an ac that small is gonna overwork your ac, too, b/c it is refilling every 10 seconds (if that) of gun use. The gun sounds starved for air. (I am returning it for an AirCat/NitroCat 1250k because it requires less CFM and has same foot pounds torque.)
It can't even remove the hub nut off this 95 honda civic i play with. (neither can my generic 1/2" air impact wrench rated at 750 ft lb. torque., 4CFM at 90 psi: so a bigger than 1/2" air impact wrench is justified to me)
I noticed a decent jump in power on my 1/2" impact when i went up to a 1/2" hose, but i just want something that will remove my hub nut, and any future nut. Some here say a shorter hose would make a big difference, maybe i will try that, too.
Getting ticked off thinking about having to purchase a bigger compressor... Unless i am able to remove the hub nut with a shorter hose and more psi... Learned a lesson about buying an ac:
Buy the biggest compressor you can get that still uses 120V (which will probably only be 6 or 7 cfm) unless you plan on never changing an axle. (I'm too small and weak for hand tools. I tried heating it.)
CFM is like the ONLY thing that matters on an ac.
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ez-duzit
Well-known member
You can re-sell it and buy an adequate unit.
i might be interested in selling this central pneumatic earth quake 3/4" air impact for $170. used only once on that weak husky ac. I oiled it a lot too. and i would recommend it for big trucks and for those who already have a big ac.
The Husky i have used very little over the last 1.5 years and will sell for like 70$.
would def recommend the husky ac for tires and nails and light airbrushing and other stuff that i cant think of.
to replace with a HF 29 gallon 150 psi vertical ac (6 or 7 cfm)
and an aircat 1250k.
The Husky i have used very little over the last 1.5 years and will sell for like 70$.
would def recommend the husky ac for tires and nails and light airbrushing and other stuff that i cant think of.
to replace with a HF 29 gallon 150 psi vertical ac (6 or 7 cfm)
and an aircat 1250k.
sberry
Banned
You wont gain much, there is only so much power gonna come thru the little wall outlet. It seems the concept that that dinky comp isn't going to run a 3/4 air gun is hitting home. Probably demands 50 or 60 cfm, gonna be out of air before it even gets up to power.
sberry
Banned
Assuming one has a 6 gallon tank with a 1/2 hose hooked to it and its pumped to 125, how long before it isn't 125?About a second?
sberry
Banned
I should have said 1/2 here.
sberry
Banned
If a guy waits till the comp shuts off it adds to the problem, the best air from a small unit will be while the comp is running and just prior to kick off. A good operator with a sander and maybe even air gun with a small unit should be able to make it run steady and use the air off the top so to speak.
1 brief break and I can sand almost steady with 3 hp. I have a lot of tank on, about 200 gallons, I have 2 comps but only leave 1 on. It was off the other day when I started sanding which means system will be down to kick in at 135, the comp had been running a couple minutes which meets about half the demand and I was done before air was an issue.
A thing that would help is a momentary or flow switch that would start as soon as the tool did so it isn't waiting to 90# tank pressure before getting the pump going.
In the end its good way to get some understanding and it is really cheap education, the problem its a slow way to learn.
This is why I harp on some of these specific themes,,, they are ones I learn hard and slow, smarter engineer types can learn faster in most cases but I am not always sure how long it takes for it to be an instinct to use a hose. Over 30 yrs as a mechanic and just now really getting a feel for the reactions of flow/pressure drop in relation to all the factors including being on a tank type system,,, many things would be easier to understand provided it was on a steady supply like city water.
1 brief break and I can sand almost steady with 3 hp. I have a lot of tank on, about 200 gallons, I have 2 comps but only leave 1 on. It was off the other day when I started sanding which means system will be down to kick in at 135, the comp had been running a couple minutes which meets about half the demand and I was done before air was an issue.
A thing that would help is a momentary or flow switch that would start as soon as the tool did so it isn't waiting to 90# tank pressure before getting the pump going.
In the end its good way to get some understanding and it is really cheap education, the problem its a slow way to learn.
This is why I harp on some of these specific themes,,, they are ones I learn hard and slow, smarter engineer types can learn faster in most cases but I am not always sure how long it takes for it to be an instinct to use a hose. Over 30 yrs as a mechanic and just now really getting a feel for the reactions of flow/pressure drop in relation to all the factors including being on a tank type system,,, many things would be easier to understand provided it was on a steady supply like city water.
sberry
Banned
Even poco electric,,, relatively stable and can provide more to the service than the normal user can demand, not so with small air comp or water wells. This all actually effects piping efficiency,,, put 30# down a garden hose or 60#, 2x difference volume on the same system a minute later.
Now it isn't a 5cfm comp at 90,,, it used 10cfm for a second, then some at 90 and now making 5 at 40, each step down adding loss, increasing the hose would help a little to try to meet demand but soon that would be irrelevant.
Now it isn't a 5cfm comp at 90,,, it used 10cfm for a second, then some at 90 and now making 5 at 40, each step down adding loss, increasing the hose would help a little to try to meet demand but soon that would be irrelevant.
sberry
Banned
If a guy must have 120V it looks like those 30 uprights would be the best. Some say 150 but never used one, heard it works. Keeping a short hose would really help an air gun, not any real benefit with a rotary tool as it is going to run out of air shortly anyway but with limited and dropping head pressures it or larger hose couldn't hurt. I use a 1/2 on my service truck but have a longer hose and larger tools. Not in restricted environment although I could use a whip.
sberry
Banned
I really been working I plumbing 5 decades, really over the last 5 years got way more instinctual "feel" or understanding to make running it all a reflex where I can get all of it out at a rate that doesn't drop system pressure etc.
How much one can apply before the pressure falls off, if its going to work or not, people always visualize circuits as being 20A but we are only drawing a pinch off most the time and occasionally 13A and not at long distance, the part of a general you may be on may be shorter etc etc and then some. Difference between use and demand and duty cycle, it all goes together.
How much one can apply before the pressure falls off, if its going to work or not, people always visualize circuits as being 20A but we are only drawing a pinch off most the time and occasionally 13A and not at long distance, the part of a general you may be on may be shorter etc etc and then some. Difference between use and demand and duty cycle, it all goes together.
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theoldwizard1
Well-known member
Good info !
theoldwizard1
Well-known member
I think the proper way to answer the question (CFM doesn't really matter with a impact gun, Right?) is can the required CFM be delivered to the tool (impact gun) at the required PSI for the length of time that the tool is ON.
Bigger hose and connectors help but ONLY IF the outlet from your tank and regulator are not limiting the flow,
Can a cheap little 1/2 hp 3 gallon pancake power an impact to remove lug nuts ? Yes, most of the time. If you have to hold the trigger longer than 10-20 seconds on any of your lug nuts, expect that you will have to wait for the tank to refill.
Why someone would buy a compressor to simply remove lugs nuts is beyond me ! I have a good portable compressor (2 hp, oil lubed), but there are times when it is less hassle to just use my 1/2" breaker.
Bigger hose and connectors help but ONLY IF the outlet from your tank and regulator are not limiting the flow,
Can a cheap little 1/2 hp 3 gallon pancake power an impact to remove lug nuts ? Yes, most of the time. If you have to hold the trigger longer than 10-20 seconds on any of your lug nuts, expect that you will have to wait for the tank to refill.
Why someone would buy a compressor to simply remove lugs nuts is beyond me ! I have a good portable compressor (2 hp, oil lubed), but there are times when it is less hassle to just use my 1/2" breaker.
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sberry
Banned
I got to agree, buy a breaker bar and 4 way or battery impact.
theoldwizard1
Well-known member
4 ways are "old school cool" !
Just don't use them to do the final torquing of your lugs. Way to easy to over tighten !! (Learned at age 15 !)I keep a 5 gallon twin stack next to my 60 gallon for small jobs like rotating tires. It charges in no time and doesn't need to recharge until after the 5 nuts are off one wheel. It is actually faster and easier than pulling out the breaker bar. Besides, I don't think anyone buys a portable just for lug nuts. I've done suspension work on rusted sedans with it and not had an issue with power.
Given that I can also run an air hammer, nailer, etc. off it it's probably less of an indulgence than getting a battery powered impact. YMMV.
Im never gonna buy an electric impact wrench, then i gotta buy an electric hammer gun, electric tire filler, electric sandblaster, electric drill electric this and electric that.... NO - all will be air powered, because i don't mind lugging around my compressor. If some situation calls for electric i will get it, but i havent encountered anything like that yet.
I got my hub nut off, finally, using the 1/2" impact wrench 750 ft lb torque, it finally magically worked after i cranked up the psi over 90, oiled the gun a lot, and upgraded to 1/2" thick hose. even though the outlet aint a 1/2" on my compressor, bigger hose helped a lot.
Im still kicking myself for buying the 3/4" impact wrench, thanks to this forum and it's people who talk out of there asses! (except a select few) I am returning it, and MAYBE get the aircat 1250k for the future. Unless someone want to buy the 3/4" for $180 (retails $250) http://www.harborfreight.com/34-in-professional-air-impact-wrench-68423.html
i know it would be an awesome gun for the price, if your compressor is at least 9 CFM.
I got my hub nut off, finally, using the 1/2" impact wrench 750 ft lb torque, it finally magically worked after i cranked up the psi over 90, oiled the gun a lot, and upgraded to 1/2" thick hose. even though the outlet aint a 1/2" on my compressor, bigger hose helped a lot.
Im still kicking myself for buying the 3/4" impact wrench, thanks to this forum and it's people who talk out of there asses! (except a select few) I am returning it, and MAYBE get the aircat 1250k for the future. Unless someone want to buy the 3/4" for $180 (retails $250) http://www.harborfreight.com/34-in-professional-air-impact-wrench-68423.html
i know it would be an awesome gun for the price, if your compressor is at least 9 CFM.
sberry
Banned
Finally cranked the air??????????????????
no matter how you slice it, a small compressor won't always do the job. regardless if it says it has 5cfm at 90psi, or 10cfm at 90psi. the outlets on it might not be large enough to run some high consumption tools that say they take an average of 8cfm to run. but in reality do that in large bursts of 20-30 over short uses. and some compressors just don't have the outlets capable of allowing that kind of pull. theres a reason i never pull out my 3/4 Chicago penumatic impacts at home. they hurt more than help unless you swap out all the fittings to 1/2" and put a 10foot hose on it
you should consider grabbing electric, i've got a wide array of air tools as well as electric, and i can't remember the last time i used a pneumatic drill over an electric one. and i'm slowly switching to impacts the same way. the flip side is that there are some super compact pneumatic impacts that can get in some tight spots vs electric. but where there is a will, theres a way. and the peace and quiet of not running a compressor can be nice on lazy days.
touché - i got the advice i paid for
yea i finally cranked the air up, sberry, but in the manual it clearly states not to -
so it must shorten tool life.
i would consider an electric impact if it was super compact
and i ran into a situation where i had to have it.
about that axle nut, im only 140 lbs. at the most, i had a breaker bar, and a long pipe on the end and nut wouldnt come off, and i wanted to do this on my own. I was about to try hand tool method again (had my little compressor not worked) only this time with an extension on the breaker bar, supported at the end by a scissor jack, so that it held the socket on the nut firmly as i try to torque it.
just learned i need to be using impact sockets, as opposed to regular sockets, and also never use a 12 point with an impact because it will round the nut off as it takes it off. This is how i know i'm a noob
yea i finally cranked the air up, sberry, but in the manual it clearly states not to -
so it must shorten tool life.
i would consider an electric impact if it was super compact
and i ran into a situation where i had to have it.
about that axle nut, im only 140 lbs. at the most, i had a breaker bar, and a long pipe on the end and nut wouldnt come off, and i wanted to do this on my own. I was about to try hand tool method again (had my little compressor not worked) only this time with an extension on the breaker bar, supported at the end by a scissor jack, so that it held the socket on the nut firmly as i try to torque it.
just learned i need to be using impact sockets, as opposed to regular sockets, and also never use a 12 point with an impact because it will round the nut off as it takes it off. This is how i know i'm a noob
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sberry
Banned
You need to put this in context and we been trying to say for 3 pages you don't have enough air pressure. Running it all day at 175 will shorten life, you couldn't wear out a gun with 2 or 3 of those comps.
It isn't going to hurt the gun in the least. If you were to put a pressure gauge at the inlet of the gun and watch it while you're putting the gun under a load, you would see that the air pressure that the gun is seeing during use is far below the 90 psi required for peak rated power. Every shop I've ever worked in ran around 120 to 140 psi static air pressure to compensate for the pressure loss from the (usually 3") hard line plumbed in the wall. A good 3/4" gun can drop that 140psi to 100 or less through a long 1/2" line, with no loss of head pressure at the compressor. In your case, compressor head pressure is dropping as soon as you hit the trigger, even if the line is adequately sized. You need all the head pressure you can get so those first few strokes of the gun have something close to the rated air pressure and volume flowing at the gun's inlet. After that, you might as well hang it up till the compressor recovers.
dnschmidt
Well-known member
Impacts use a ton of air. Luckily, they use it sporadically. You have a much better chance of using an impact with an undersized compressor than you do a die grinder. Typically you use a three second burst with an impact and the job's either done or it ain't going to happen. A 20 gallon compressor can handle that.
With a 3/4" impact 1/2" hose with 3/8" couplers are mandatory. Otherwise the tool will never reach it's designed power level. If you can supply 30 cfm for three seconds that's typically all you need.
With a 3/4" impact 1/2" hose with 3/8" couplers are mandatory. Otherwise the tool will never reach it's designed power level. If you can supply 30 cfm for three seconds that's typically all you need.
The key word here is duty cycle which is on time over off time.
Impact duty cycle is dependent on CFM. Granted there is the extreme low, but impacts are one of the most forgiving of low CFM units as most people that don't own a large compressor won't be in the need of a high duty cycle impact use.
Example: Take off one lug nut, let it charge for a minute between other nuts (low duty cycle) vs quickly zip off all 5 in rapid succession (high duty cycle).
Impact duty cycle is dependent on CFM. Granted there is the extreme low, but impacts are one of the most forgiving of low CFM units as most people that don't own a large compressor won't be in the need of a high duty cycle impact use.
Example: Take off one lug nut, let it charge for a minute between other nuts (low duty cycle) vs quickly zip off all 5 in rapid succession (high duty cycle).
Sticks McGee
Well-known member
I have a 33 gallon oiless sears compressor at home and here is what I found.
With a good 3/8" hose and hi flo fittings (the same ones I use at work) and a known good IR 1/2" drive impact and the compressor with 150 lbs or air, I could not get some lugs busted off of my dad's F150 truck. I ended up doing some investigating and what I found was is that my craftsman compressor has the air outlet coming out of the tank with a 1/4" NPT fitting running through a tiny hose to a tiny manifold and thru a regulator, out through this manifold and to a coupler that my air hose plugged into. I decided that my issue HAD to be a highly restricted flow. Just over from the manifold was a fitting on the tank (1/4" NPT) with a pop off valve threaded into it. I went and bought myself a T and put my coupler right there so I could bypass the regulator, manifold and restrictive piping. It made all the difference in the world. The impact now acts as it should and when I pull a wheel off the air gauge on the tank barely even drops pressure. I have ran a die grinder with a cut off wheel on it to cut a few things and had it run several minutes without slowing down. yes the compressor kicked back on to fill the tank but I did not have to stop and wait for the compressor because it ran out of good air flow. Now I am not saying I could continuously run an air D/A sander but it now does what it needs to do to supply me air..
With a good 3/8" hose and hi flo fittings (the same ones I use at work) and a known good IR 1/2" drive impact and the compressor with 150 lbs or air, I could not get some lugs busted off of my dad's F150 truck. I ended up doing some investigating and what I found was is that my craftsman compressor has the air outlet coming out of the tank with a 1/4" NPT fitting running through a tiny hose to a tiny manifold and thru a regulator, out through this manifold and to a coupler that my air hose plugged into. I decided that my issue HAD to be a highly restricted flow. Just over from the manifold was a fitting on the tank (1/4" NPT) with a pop off valve threaded into it. I went and bought myself a T and put my coupler right there so I could bypass the regulator, manifold and restrictive piping. It made all the difference in the world. The impact now acts as it should and when I pull a wheel off the air gauge on the tank barely even drops pressure. I have ran a die grinder with a cut off wheel on it to cut a few things and had it run several minutes without slowing down. yes the compressor kicked back on to fill the tank but I did not have to stop and wait for the compressor because it ran out of good air flow. Now I am not saying I could continuously run an air D/A sander but it now does what it needs to do to supply me air..
same deal with my 33gal which is why i dont run big stuff on it. don't want to hassle tearing it apart to get to the wide openings to run big tools.
also why OP's little compressor is likely to never be able to run a big gun no matter what size fittings is on it, it likely has an even smaller opening than the 33gal craftsman compressors.
im saying though, i have two impact wrenches, one is 1/2" drive the other one i already sent back had 3/4" drive. My ac couldnt power the 3/4"drive. My ac powers the 1/2" drive just fine. my compressor is 4cfm. the gun uses 4cfm at 90psi, and it removed the hub nut, and many other nuts that i would have never been able to remove by hand.
but i see what you mean, if i had a gauge at the guns inlet, it would read lower than at the tanks outlet, so its ok to crank it up. And i could also benefit from some spare CFM's too. I have been looking at new ac's still. but that Husky is super portable and cheap for 4 CFM's. It doesnt run in cold weather at all though.
Everyone on here states that you need these super high CFM levels (20-30+) to use an impact, but i say no, it all depends on the size of the gun and the nut/bolt. And i have seen people have to use an impact for extra amounts of time on big seized truck wheel bolts, so extra CFM and a big tank will help you there. But a big 20 gallon tank doesnt mean jack if you have a low CFM.
i see the point with duty cycle affects from CFM too
i'm not the Op of this thread, however i agree that my little ac will never run a 3/4" drive, or probably any gun over using 4CFM@90PSI. But you gotta start somewhere. Again the best thing to help the little ac i found was upgrading to a thicker hose
but i see what you mean, if i had a gauge at the guns inlet, it would read lower than at the tanks outlet, so its ok to crank it up. And i could also benefit from some spare CFM's too. I have been looking at new ac's still. but that Husky is super portable and cheap for 4 CFM's. It doesnt run in cold weather at all though.
Everyone on here states that you need these super high CFM levels (20-30+) to use an impact, but i say no, it all depends on the size of the gun and the nut/bolt. And i have seen people have to use an impact for extra amounts of time on big seized truck wheel bolts, so extra CFM and a big tank will help you there. But a big 20 gallon tank doesnt mean jack if you have a low CFM.
i see the point with duty cycle affects from CFM too
i'm not the Op of this thread, however i agree that my little ac will never run a 3/4" drive, or probably any gun over using 4CFM@90PSI. But you gotta start somewhere. Again the best thing to help the little ac i found was upgrading to a thicker hose
One can (and I have) easily run an impact wrench off of an air tank with no compressor at all installed on it, -0- cfm. Just pressurize it to 120 or whatever and haul it out to the field. You just won't be able to run it for long ...
on a similar note for an idea. if you want to run something big like a 3/4" or 1" impact to get that super big blast of power to get something off.. buy a secondary tank with a large outlet on it, hook your compressor up to that tank. and put your 1/2" directly out of the secondary tank. this way you have a high CFM flow from the secondary tank which will refill from the main tank, without having to change out a bunch of fittings and lines on the main compressor. you might be refilling it a lot, but you'll get the breakawy power you need.
great idea, Kracin. what secondary tank with larger outlet do you or anyone recommend?
Mandres: i too sometimes fill my ac tank up, unplug the ac, and wheel it to a junk car, and use the impact real quick before air is gone. But how is that ZERO CFM?
Mandres: i too sometimes fill my ac tank up, unplug the ac, and wheel it to a junk car, and use the impact real quick before air is gone. But how is that ZERO CFM?
Just meant to illustrate that even a "zero cfm" compressor can run an impact gun long enough to do the job sometimes
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