Impact wrench

[OREGON85]

My wife got me an impact wrench and I am trying to figure out why it doesn't perform too well. It says it does 350 ft/lbs, but it seems to only torque lug nuts to about 80.

What is the limiting factor with a small air compressor? Does low CFM mean low mean more wait time or less torque? Is CFM the speed the compressor fills or puts air out?

Thanks!

 

[gijohn40]

usually on the bottom there is a knob that you can turn that increases the torque or decreases it... yours might be on the lowest setting...

 

[I Lean]

The 350 is typically the removal rating, not necessarily tightening torque.

Low CFM means more wait time to refill the tank, or less ability to keep up with usage. If you're getting full pressure to the gun, you're getting the full torque it's capable of.

 

[Cherokeester]

Make sure you oil your gun! My impact guns generally don't get the advertised torque ratings but I figure that is what a good torque wrench is for.

 

[Unimog]

You will get a little more juice out of it if you put a lead hose on it before the quick connector. The way most of us put a quick connect right at the tool causes a restriction and accompanying drop in pressure at the tool.

 

[rambrush]

Plus my thoughts are that it the torque is supposed to only be utilized to remove the object.
Sure run the lug nut down tight but use a proper torque wrench or extension made for the manufactures specifications. The studs can only stretch so many times before they become fatigued and break at the wrong time.
I use a cp 745 with a 3/8" x 3' whip it has the swivel fitting at the gun. Generally a good sized storage tank on the compressor is a good thing so there is reserve available.

 

[OREGON85]

Low CFM means more wait time to refill the tank, or less ability to keep up with usage. If you're getting full pressure to the gun, you're getting the full torque it's capable of.

Okay, thats what I was thinking, but I wasn't sure.

I not sure how a lead hose would help, could someone explain that a bit?

 

[UNSTUCK]

It wont, much. What he means is that the QD has a 1/4 inch opening. This allows just a small amount of air to enter the gun. So if you run a whip, that puts the QD a few feet away allowing the whip to act as a small air tank. But it's so small that after one or maybe two hits, that "tank" is empty and you are back to getting air from the compressor witch will pass through that 1/4 inch opening again.

What size gun is it and how old is it? What size hose are you using? CFM IS everything. Most guns have a rated torque at a given CFM. One of my 1/2 inch guns is an OLD snap on. It was the best gun in it's time. But it has hundreds of hours on it and is weak. Keeping it oiled helps, but it's just like an old engine. They get tired.

 

[Caleb]

You also get what you pay for. If it's a cheap CH, Harbor Freight, etc gun, then don't expect too much from it. Get a nice IR, Snap-on, etc gun and you will see a night and day difference.

 

[MikeGyver]

Thats probably the removal rating AND reaching that rating takes like over 10 seconds (not 1 or 2).

 

[TEAM FRED]

More air pressure = more torque.
If your tool is rated at 100 lbs that means you need 100 lbs with the tool running.

 

[OREGON85]

It is a new Kobalt. I've only used it once and I was using a 50ft long 3/8'' air hose.

Reverse says it does 370 and 350 on the highest setting forward at 90 psi. At 150 psi it does 80-90 ft/lbs forward. Although my compressor is pretty small and CFM isn't too high, it seemed to keep up okay.

 

[pfinder]

i have a cheap-o- harbor freight impact that claims to do 425 pounds of torque and i have beat the living hell out of it and it keeps up. but i always use a torque wrench when torque settings are needed