Alan Horowitz wrote:
>
>> Pardon the fairly wide net of groups I'm posting to; I'm trying to
>> catch the guy who knows how to answer this question.....
>>
>> Harbor Freight has a 5-gallon, 125-PS air tank that is small enough
>> to be hauled around inside a rolling peice of luggage, which is how I
>> would do it in my field-service type of work.
>>
>> Can that amount of air, run a impact wrench long enough to crack a
>> tough-dog nut to the point where a normal long-handled hand wrench
>> would handle it? My experience is that I can do it by hand once it's
>> down to 70 foot-pounds of torque. Depending upon how badly placed the
>> thing is inside a crowded cabinet, above/below my arm level, etc. But >> let's use 70.
>>
>> Given an air tank rated in X gallons @ Y PSI, how do I calculate the
>> time it would deliver air at Z psi to an impact wrench at a
>> consumption rate of Q cfm, where Z is smaller than Y? And how much
>> power is that, in terms of (let us say) watthours?
You don't need to go through all this exercise when all you want is high torque long enough to break free a difficult nut. It is only torque you need, not "work."
Buy a really good electric impact and forget air. After all, you can always put a pipe wrench on the extension to give the power tool a boost if needed. That's been my solution to "need more torque" since I was a kid with worn out impact tools. A 3/4 impact driver, now there's a man's tool. If air you won't run that very long off a 5 gallon tank.
Don't forget, air pressure in a small tank with an undersized compressor drops rapidly as does the torque it produces. An air impact will maintain torque running continuously all day, till you plain wear it out.
> Who sells a flexible drive that is (say) five feet long, and can >> handle the torque required to bust open a rusted nut, if the >> emplacement is such that I can't get a power tool directly onto the >> socket?
You cannot direct the torque 100% in a flexible drive
5 feet long.
If this is for your work, Alan, I suggest you invest in buying > one of the small tanks and trying it out. Time is money ..
If he is on the clock already, time is money in his pocket.