[mikeweb]

Hey guys,

Im trying to get this stubborn driveshaft spindle nut off but it doesnt want to budge. Im running an oiled 20gal 5.7cfm@90psi compressor with an Ingersoll Rand twin hammer 1/2" 600ftlb impact gun.

My question is, would I see better results with a higher rated impact gun or a larger cfm compressor?

[59 wagon man]

larger comp way undersized

[Rambo_The_Dog]

Originally Posted by 59 wagon man

larger comp way undersized

59 wagon man is correct - you're barely at the CFM you need for the minimum impact to operate...

...Air Consumption: 5.0 cfm/142 l/min.; @ Load 24 cfm/680...

[oldred]

Make sure you don't have that gun choked down with a small hose and/or fittings, you should have a 3/8" hose and fittings since 1/4" will reduce the power a LOT. You can use that little compressor if you start off with it at full pressure but you will only have full power for a few seconds so as soon as it kicks on stop and let it recharge.

[mikeweb]

Ok, thanks for the info guys.

Im running 3/8" hose (with 1/4" ends) and 1/4" couplers/fittings.

Would it be ok to use the same hose (and purchase a 3/8" adapter) then just get 3/8" couplers/fittings?

or would it be pretty much the same thing as I currently have?

[oldred]

Just make sure it is not choked down at any point, it only takes one place.

[427v8]

Originally Posted by Rambo_The_Dog

59 wagon man is correct - you're barely at the CFM you need for the minimum impact to operate...

Nope doesn't matter.
The compressor rating only becomes important when it's running, it shouldn't even start if he's only taking off one nut.

Now if he's running it continusly all day long it's a different story

Untill the compressor starts it's all about getting air out of the tank, like said above, use the big connectors...

Keith

[Rambo_The_Dog]

Originally Posted by 427v8

Nope doesn't matter.
The compressor rating only becomes important when it's running, it shouldn't even start if he's only taking off one nut.

Now if he's running it continusly all day long it's a different story

Untill the compressor starts it's all about getting air out of the tank, like said above, use the big connectors...

Keith

His compressor doesn't put out enough CFM to allow the impact gun to work at the max advertised torque of 600ft lbs - only the min. which is around 150ft lbs of torque at 5.0 cfm - the connector size will not amount to much if any difference if the required force to break the nut loose is greater than 150ft lbs.

[oldred]

Originally Posted by Rambo_The_Dog

His compressor doesn't put out enough CFM to allow the impact gun to work at the max advertised torque of 600ft lbs - only the min. which is around 150ft lbs of torque at 5.0 cfm - the connector size will not amount to much if any difference if the required force to break the nut loose is greater than 150ft lbs.

I have to disagree, until the compressor kicks on the gun will not know what size the compressor is since the tank discharge rate is determined by the size of the hose, fittings and the tool demand. With that little compressor he will have only a few seconds at full power before he will need to stop and let it recharge but with an impact that will usually work out ok since a few seconds is sometimes all it will take. The connector size will make a big difference and will be the determining factor as to what CFM is available to the gun until the tank discharges down to a pressure low enough to affect flow at which point he will have to stop and wait, if he had a bigger compressor with a flow rate that matched the gun he would not have to wait.

[Rambo_The_Dog]

Originally Posted by oldred

I have to disagree, until the compressor kicks on the gun will not know what size the compressor is since the tank discharge rate is determined by the size of the hose, fittings and the tool demand. With that little compressor he will have only a few seconds at full power before he will need to stop and let it recharge but with an impact that will usually work out ok since a few seconds is sometimes all it will take. The connector size will make a big difference and will be the determining factor as to what CFM is available to the gun until the tank discharges down to a pressure low enough to affect flow at which point he will have to stop and wait, if he had a bigger compressor with a flow rate that matched the gun he would not have to wait.

Maybe I don't understand the specs on the impact gun...?

Air Consumption: 5.0 cfm/142 l/min.; @ Load 24 cfm/680...

I read this as

142 lbs @ 5.0 CFM minimum (I'm thinking this would be the most he could get with a burst like you described since his compressor is rated only @ 5.5 CFM)

680 lbs @ 24cfm under load (I'm thinking this would be the max output of the impact thus needing substantially more CFM to get a similar burst to this level of torque)

I thought I was wrong once, but I was mistaken...

[427v8]

You actually believe the specs printed on Impact wrenches?

I bought a cheap 400 ft/lb wrench that couldn't take the lug nuts off my car.
(torque wrench said 90ft/lbs to remove them.)

A more expensive tool with only slightly better specs does it easily, Hmmmm

[SteveU]

No need to get adapters & 3/8" fittings. Go to a parts store that sells automotive paint supplies & get some 1/4" HVLP fittings & connectors, they allow more FLOW which results in more POWER. Looking thru the holes in the type V HVLP fitting compared to the type A or M that most everyone uses is like the difference between a .357 and a .22. The larger hole makes it easier to oil your tools and keeps everyone from borrowing them as they won't work on the type A or M connectors BUT, the type A & M connectors work with type V connectors so you get the best of both worlds I don't know about the torque involved but my Nitrocat running the HVLP fittings took off a spindle nut that my neighbor who weighs 200 lbs bouncing on the end of a 4' cheater bar wouldn't budge. This was on an older 4wd PU in the rust belt that has been used for plowing snow, etc. Maybe try alternating between tighten & loosen, sometimes that will break something loose that's being stubborn.
Good Luck,
Steve

[oldred]

Originally Posted by Rambo_The_Dog

Maybe I don't understand the specs on the impact gun...?

Air Consumption: 5.0 cfm/142 l/min.; @ Load 24 cfm/680...

I read this as

142 lbs @ 5.0 CFM minimum (I'm thinking this would be the most he could get with a burst like you described since his compressor is rated only @ 5.5 CFM)

680 lbs @ 24cfm under load (I'm thinking this would be the max output of the impact thus needing substantially more CFM to get a similar burst to this level of torque)

The discharge rate and pump charging rate are two different things. The published CFM output is the recharge rate at which the pump charges the tank and if it equals the demand then the compressor will keep up but if the demand exceeds the recharge rating then of course the compressor will run out of air with the amount of the demand determining how fast. The actual air CFM rate available from the compressor can be quite a bit more than the compressor rating BUT only until the pressure drops to a point low enough to slow the flow, in the case of this small compressor/impact wrench only a few seconds. With a big enough hose and fittings that little compressor could supply a 50 CFM discharge rate but probably for less than a second!

Also that air consumption you have listed is the metric conversion-5 CFM/142 Litres per Min. @24 CFM/680 Litres per Min

[oldred]

Originally Posted by SteveU

. and keeps everyone from borrowing them

I would always get a kick out of seeing the puzzled look on someone's face when they picked up one of my old Snap-on 5/8" drive sockets and tried to put it on their ratchet No one borrowed MY sockets!

[mikeweb]

wow, lots of good info guys

Would I be better off getting some HVLP 1/4" plugs/couplers or go with regular 3/8" 's?

I have a 50' 3/8" hose w/ 1/4" ends