question about air pressure for air tools

[The motor guy]

So if the air tool states 90psi maximum. Is that when the tool is running that you can run 90psi through it or is it not running? Cause when I set the regulator on the compressor to 90 psi when you start using the tool it drops to around 70psi on the regulator. So is it 90psi when your using the tool or 90psi when not using it?

 

[229]

90psi running will be fine if it is a quality tool. Oil daily if you remember.

 

[kasedian]

Turn your air up as high as it will go. Unless you're using some Harbor Freight junk, you won't have any problems.

 

[Trav]

90 psi with the tool running.
Keep in mind some tools e.g. sand blasters, DA sanders, cut off wheels etc have high CFM consumption and can drop the pressure quick on smaller compressors,

On tools like this with a smaller unit (60 gal 3HP or less) i bleed the top of the tank off by running the tool for about 15 sec then setting the running pressure, on big units 80+ gal 5HP+ it doesn't matter.

Note Some real small units with oil less pumps have 5HP on the label, this is some mickey mouse calculation the real number is about 1.5 HP

 

[The motor guy]

Ok. I'll just set it at the required psi for the tool while running. Thanks! I have a craftsman 33 gallon compressor so it runs most tools with no problem.

 

[JHZR2]

Is pressure or flow more important? If I get 100cfm at 75 psi or 50 at 90, what is better?

 

[tom slick]

Originally Posted By: JHZR2
Is pressure or flow more important? If I get 100cfm at 75 psi or 50 at 90, what is better?


Depends on the tool but most "pressure" or "power" problems are actually flow problems.

 

[Donald]

When you start using the tool and the regulator drops to 70, what is the pressure in the tank before the regulator? While as others have pointed out 70 should be OK, the problem may be that you need all 1/2" connections in the regulator and maybe hose. Its also possible that some regulators of the same size (1/4") may be more restrictive than others.

I am almost complete going to all 1/2" with respect to filter/regulator/lubricator. And they are all IR. An upgrade from 1/4" HF.

Also a larger tank could generally help. And if the compressor is some distance away, then a local tank could help.

Years ago I worked in a roof truss factory and they had a monster compressor like 25HP with a dryer, and I am not sure what size tank. Next to each machine they also had local tanks. While the actual pressing of the plates was hydraulic, they did use air for clamping the wood, etc.

 

[JetStar]

And that 90 PSI would be right at the tool, at the end of the hose, while working. I made a little block with fittings and a pressure gauge. If you can't maintain 90 at the tool (provided you have adequate source pressure), then you have a flow problem. This can be caused by plumbing and fitting sizes, including right at the tank, regulators, and hose. I have also found over the years that junk air tools use a lot of air, but don't do much work. I asume it's blow by.

http://www2.northerntool.com/air-compressor-buyers-guide.htm

 

[tig1]

Originally Posted By: kasedian
Turn your air up as high as it will go. Unless you're using some Harbor Freight junk, you won't have any problems.


Actual 90PSI for air tools. As for the HF remark, I have several HF air tools and they all work very well.
Straight and 90% die grainders. 1/4 inch air rachet is outstanding. Air chesel works great.

 

[deeter16317]

I've went over that a couple times on a cut-off and impact...with 150psi and 1,100CFM available, it sure makes air tools sing!

But as others have stated, the inlet pressure of 90psi should be your goal for optimum power...but it should still work at lower pressures.

Since you've stated the pressure drops at the compressor/regulator to 70psi, that indicates either the regulator or the supply line feeding the regulator is the problem (your hose and fittings are likely fine). I'm going to guess its like my CH and they have plastic push-loc 1/4-inch tubing piping the OE regulator? To solve that problem, I pulled a plug from the side of my compressor tank, and ran bigger hose and a separate regulator for using higher consumption tools like sanders and impacts.

 

[Trav]

Quote:
If I get 100cfm at 75 psi or 50 at 90, what is better?


At 90 would be better but if your getting 100 CFM even at 50 PSI it doesn't matter as even at 90 it would still have lots to spare.
It would have to be a gigantic 2 stage unit to deliver 100CFM though.