Torque & PSI equivalency for air compressor & air ra

[Arky]

Is there a chart somewhere that shows air compressor PSI equivalency for torque/foot pounds?

For instance, is 125 PSI on my air compressor enough torque to put on my lug bolts with an air rachet? How about the alternator fan bolt?
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Arky
62 Single Cab (sold)
67 Beetle (sold)

[chrisflstf]

There is no chart to convert PSI from your compressor to torque. The amount of torque is tool depedent. My 1hp compressor will remove a 150FT LB nut secured with Red loctite with an Impact Wrench.

[arthurnugen]

Don't know about a chart, but I would not use an air ratchet to put on your lug nuts. 85-90 ft.lbs. is correct. If you use an air ratchet/impact hammer it is really easy to over torque and stretch the nuts out. I always use my trusty click-type torque wrench with lug nuts, or anything needing a torque spec for that matter.
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[VWBobby]

A cheap torque wrench is great for lug nuts and all kinds of parts that you should be using a torque wrench on. Good torque wrenchs are expensive, and great for building engines but not needed for the average DIY'r.

Air rachets are not very good for anything besides quickly disassembling an engine or part. I would not use them to tighten anything except for the most meaningless part...too inaccurate and easy to overtorque.

[Mikee]

the have torque sticks for your impact gun, that will give you acurrate torque will using your impact.

http://www.torquestick.com/

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[chrisflstf]

Disassembly is what I use Impacts for. Anything that is important gets torqued.

Watch your hands if your using chrome sockets for impacts. If the socket is worn/chipped, a slice of chrome will do a number on your hand.

[Arky]

Thanks guys. I ordered a 90 foot lbs. torque stick.

I never thought about stretching the lug bolts out. I was only thinking about getting them tight enough.

I've used the impact wrench 2-3 times now on my bug and bus at 125 psi. Should I replace the lug bolts? Any way to tell if they've been stretched? I'm guessing it will be unnoticable to the eye.
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Arky
62 Single Cab (sold)
67 Beetle (sold)

[BarryL]

So how does the Torque Stick work? It breaks off at full torque? Or does the girl stand there and tell you when to stop?

[VWBobby]

It would take quite a bit of force to stretch them, unless you are cranking on them with a (true) 300+ ft lb impact wrench... Usually overtorquing the bolts will pull the threads or warp the drum/rotor.

2 hands on a 4-way lug wrench is plenty of torque. If you need to put wheels on faster than a 4-way lug wrench, you shouldn't be working on a VW in my opinion. I can use a 4-way at least as fast as an air ratchet (slow compared to a impact!).

[gatorwyatt]

the torque is really just equal on all lugs not exact.you can actually break them by using them in reverse.i would use a torque wrench ,not the stick.it is designed for a saleable product to consumers like arky who read and beleive.

[Flipseat]

Torque sticks are not accurate. They will torque a nut/bolt to different specs depending on how long you use it (how long you pull the trigger on your air gun), how many PSI you're running, what impact gun you're using, how worn your gun is, and how worn the torque stick is. I use them every day to get lug nuts/bolts close, and then I set the car on the ground and torque the wheels by hand.

The difference between the torque sticks are their thicknesses. 55 lbs will be a lot thinner than 100 lbs, and thats thinner than 140 lbs, etc etc.
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Insert random important looking club initials here.

[Arky]

Yupp, I have to admit I'm pretty gullible. But thanks to all you pros I've learned a lot. I'll have fun playing with the torque stick anyway.

Note to self: Stop buying things you don't need!
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Arky
62 Single Cab (sold)
67 Beetle (sold)

[Flipseat]

[Arky]

Update: I used the 90lbs torgue stick over the weekend and found that it didn't matter how long I held down the trigger on my impact gun or how much psi I applied, it does not turn the bolts any further.

I was surprised to find the torque stick is a solid 1/2" extension with no moving parts. I expected some type of rachet on the end that stopped turning at 90lbs.

Since I have limited understanding of ?physics? is there a smart body here who can explain for the simple minded how the length and thickness of the torque stick limits torque?
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Arky
62 Single Cab (sold)
67 Beetle (sold)

[BarryL]

[Arky]

It doesn't twist (I thought it would too). It is a solid piece of metal, just like a 1/2" extension. The torque limitation is something to do with the length and thickness (sound familiar? ).

The girl was NOT included!
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Arky
62 Single Cab (sold)
67 Beetle (sold)

[Mr. Bubblehead]

My bro-in-law owns a tire shop and has the whole set of torque sticks. They operate by the same principle as the rear torsion bars in your bus. I think you have to set a certain PSI/CFM/whatever on your compressor and/or wrench for them to work properly, though.
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OGST
Samba Member #4862

[Yellowbeard]

While you're at it, check the input pressure specs for your impact wrench/air ratchet. Mine both set at 90psi. I blew the guts out of my palm nailer with 120psi. Costs more to rebuild than I paid for the damn thing...
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