Air impact wrenches

[30-9]

Hey folks here's another novice question.

Is there a formula for psi to Tork?

In an example when using the impact gun on tire lugs how do you know how tight is tight and not too tight or not tight enough.

[Lawson Cox]

Ford mechanics never used torque wrenches. Just get them "Tight".

[Scotty's 52 F3]

Impacts are not to properly torque anything. They mainly are used to speed things up.

Most tire shops will use them to remove lug nuts and run them on lightly with a torque wrench to finish.

Use them enough and you get a feel for them but, usually not used for critical torque specs.

Most people at home just run them down tight by feel. A good impact can break or strip a wheel stud/nut.

[30-9]

Thanks I wasn't going to use on anything critical. How many psi is a good level for general use (like tire lugs, shocks, etc)

[deuce_roadster]

If you must use an impact wrench to assemble something like lug nuts, (I wouldn't ever) get a 1/2" fine thread bolt and nut, put the bolt in a vice and run the nut down and see what torque it tightens to. Experiment with your equipment, what mine might do is irrelevant.

[Scotty's 52 F3]

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Most air tools are rated @ 90psi. Most people I know just use full system pressure from their compressor as there is a pressure drop across long hoses.

I used to put 175 psi to my impacts from my service truck. They were super powerful and fast but, I blew up a lot of hammers.

[Graeme / New Zealand]

Originally Posted by deuce_roadster

If you must use an impact wrench to assemble something like lug nuts, (I wouldn't ever) get a 1/2" fine thread bolt and nut, put the bolt in a vice and run the nut down and see what torque it tightens to. Experiment with your equipment, what mine might do is irrelevant.

Nothing like experimenting with your equipment

GB

[deuce_roadster]

Don't put too much torque on "your equipment"!

[36coupe]

Try using a torque limiter, basicly a extention that flexes when it hit close to a certain torque valve, then check with a torque wrench if you want.

The air pressure in and torque out depends on the type and size of gun. Not all 1/2" guns are equal.

[30-9]

Thanks guys

[42guy]

I know Snap On sells the torque limiting extensions. They come in different torque ratings.
I purchased one for 90 lbs.

[flatford8]

Alot of tire shops use " torque sticks". They come in different sizes and flex when you get the fastener tight. If you want accurate torque values I would use a torque wrench. I have a 3/8 air gun for smaller fasteners...... Mark

[john in illinois]

I have a 3/8 Dewalt lithium ion battery impact. To me it is one of my handiest tools. I use it for small fasteners,especially under the car. It is their smallest model and I use it to remove small bolts. I install fasteners just snug and tighten by hand.

I bought one of these after I watched a mechanic climb inside my combine and remove and install a bunch of nuts in cramped quarters with a small battery impact.

For air impacts I have my shop air set at 100lbs.

John

[Vics Stuff]

Just like 36coupe indicated . For larger nuts / bolts there is a tool called a torque stick. They are a special socket / extension that can be used on lug nuts and the like . They only allow the nuts to be torqued to their specific torque using a impact whench.
Vic