Thread: Air tools advice/recommendation

My experience is that manufacturers over rate compressor outputs and underrate air tool requirements.
What is the HP rating of the motor and does it have one or two stage compressor?

These guys appear to be fairly reputable.

Here's the compressor, but with a 70L tank:

http://www.westaircompressors.com.au...phase/wa20120/


IIRC somewhere I read that they rate their outputs at 90psi but I can't find it now.

And they have an air tool guide:

http://www.westaircompressors.com.au...-GUIDE-NEW.pdf

which is kind of in line with the tools I've been looking at. As usual, I find myself looking at the biggest, baddest grinders etc but maybe I need to reign myself in a bit.

Here were two of the grinders I liked:

https://www.toolmart.com.au/air-tools/sp-7200.html
https://www.toolmart.com.au/air-tools/sp-7201.html

Originally Posted by Legion

I have a new compressor, rated to 379Lpm/13.4cfm @ 90psi continuous. Having never had one before, I will be looking to build a collection of air tools. First on the list is die grinders. There are a couple I'm interested in and both are rated at "~350Lpm average, ~500Lpm max". My question is, what does this mean with respect to my compressor? How often will I overload the tools and have to back off? For comparison I have an ancient Dremel and as soon as you put any load on it the rpm drops way down and you have to back off the pressure. Will this be a similar thing, where the grinders will spin free no worries but as soon as I lean on them they'll drop right down? If so, is it better to choose slightly lesser tools with lesser torque and lesser flow requirements?

Same with a few air drills I've looked at - if it lists max consumption that is way over my compressor's output the drills will be fine for the average 5mm hole but when I want to drill a 10mm hole through 15mm plate I'll have to keep backing off to let the tank build up a bit?

It's only a small tank, 70L, so I'll be asking the compressor to do most of the work anyway.

This is a link to an air consumption chart for different air tools. It lists consumption depending on your usage cycle (how long the tools is on and how long it is off). A drill is only on and uses air when actually drilling, so your usage cycle may only be 10%. Same with a wrench. But a die grinder may be continuously on for very long periods of time and require you to calculate consumption for 100% usage cycle. http://www.google.com.au/url?sa=t&rc...77648437,d.dGY

Also consider that an air vane motor consumes most air when unloaded and at full idle rpm. As you load the motor (like when grinding) the rpm drops and the shaft power rises. For an ungoverned air motor like all small die grinders, the maximum output power at the shaft is at about half the idle speed. These are the two consumption figures given for your grinder, the lower figure is at full load and about half the idle rpm, the higher figure is at full idle rpm and no load. Both figures are at rated air pressure.

Full idle rpm depends on air pressure. The higher the pressure, the higher the idle rpm, the higher the air consumption. You can reduce both idle rpm and air consumption by reducing the air pressure.

AirMotor.gif
This is a graph I found on the net. green is shaft poer, orange is torque. Start and stall torque depend on the air pressure, so does top idle rpm and maximum output power. Air consumption depends on air pressure and actual rotor speed.

I understand air die grinders, but for many other applications air is far from the best option in my opinion.
I would rarely choose an air drill or grinder. I had the misfortune of using an Atlas Copco 9" air grinder and gutless would be an understatement. No shortage of air either, fed from 1" hose tied into 110mm poly air mains and fed from massive screw compressor.
Air tools are nice and smooth, but not nice on a cold morning.
Impact wrenches, air ratchets, riveters die grinders, jet chisels, needle scalers and similar are all good options, but I'm not so convinced on many of the others.
Why are you so keen on air tools may be a good place to start.

Originally Posted by Karl Robbers

Why are you so keen on air tools may be a good place to start.

I don't need air tools. I will still use a 4" and 5" electric grinder, for example. I wouldn't mind an air drill because I have a couple of ~$100 drills and they've both let out smoke before, when I try to drill 10mm or 12mm or 13mm holes in steel and don't go slow enough and/or stress the motor too much.

Other options are bigger hand drills, a magnetic drill, a drill press. A lot of holes I drill in situ so there's no single right answer.

Die grinders will probably get a lot of use.

Compressor was so that next year I can say "I need a plasma cutter to go with that compressor" and I can try out that lpg torch thing I got. Plus I thought it's just a handy workshop tool. Sometimes air would have been good in the past but I only had a (admittedly very good) 12V compressor putting out about 3.5cfm at 0psi.

I do a lot of stuff to my car and other similar gear and an impact wrench would be very useful, as would ratchet wrenches. I'll have to gather a whole new collection of impact sockets though since all my sockets are normal hand ratchet sockets. At the moment I use stronghands and hammers and all sorts of stupid uncomfortable things.

Air over hydraulic ram to power my tube bender would be nice ...

Lots of applications.

Most people fall down in sizing the air lines then blame the tools for poor performance and water issues.

With a simple endless air mod, you can also use your air tools anywhere you take your car:
http://www.grungle.com/endlessair.html

> I wouldn't mind an air drill because I have a couple of ~$100 drills and they've
> both let out smoke before, when I try to drill 10mm or 12mm or 13mm holes in
> steel and don't go slow enough and/or stress the motor too much.

Air drills will not let out smoke. You can stall them as often as you like, and they just restart.

> I do a lot of stuff to my car and other similar gear and an impact wrench would be
> very useful, as would ratchet wrenches. I'll have to gather a whole new collection
> of impact sockets though since all my sockets are normal hand ratchet sockets. At
> the moment I use stronghands and hammers and all sorts of stupid uncomfortable things.

Air tools are smaller and lighter than equivalent electric tools. No need for dangerous electric cords, no batteries to charge and to replace. Air tools do not create commutator sparks that could ignite petrol fumes. Air tools remain cool in use, and do not burn out if overloaded. Air tools do not need to take in cooling air like electric tools, hence can not be clogged by dust. Air tools have many times over the life time of any equivalent electrical tool (you still only get what you pay for, but at a given power and price the air tool will outlast the electric tool at least 5 fold).

Make sure you use proper air tool oil (its very thin, and must be able to absorb water). Some tools with vane motor say no need for oil.... but what they really mean is no need for oil if you accept a greatly reduced life span. Use a water coagulation filter. And a good quality air hose from compressor to tool (I found this 80Bar hose as normally used for agricultural spraying to hold up excellently for air: http://www.google.com.au/url?sa=t&rc...77648437,d.dGY. and I attach my own couplings). Make sure the air hose couplings you use are the real thing, eg if you choose Nitto couplings then buy the genuine stainless product, not cheap "nitto style" clones made of soft Aluminium or iron that rusts.

Originally Posted by cba_melbourne

>
Air tools are smaller and lighter than equivalent electric tools. No need for dangerous electric cords, no batteries to charge and to replace. Air tools do not create commutator sparks that could ignite petrol fumes. Air tools remain cool in use, and do not burn out if overloaded. Air tools do not need to take in cooling air like electric tools, hence can not be clogged by dust. Air tools have many times over the life time of any equivalent electrical tool (you still only get what you pay for, but at a given power and price the air tool will outlast the electric tool at least 5 fold).

The weight advantage of air tools is a definite plus, but the relatively inflexible air line can be a nuisance. Wurth make a beautiful 8mm air line that you could nearly lace your shoes with. As with everything Wurth branded you will pay through the nose for it.
While it is true that the tools themselves do not produce sparks to ignite flammable vapours, the cutting tools they use such as drill bits and burrs definitely can produce sparks capable of igniting said vapours.
There are definite advantages in environments such as bodyworks where dust can certainly play havoc with electrical tools.
The fact that the air that runs the tool also cools it can be both an advantage and a disadvantage. Using aluminium bodied air tools on a cold morning is just plain miserable for your poor hands. Polymer bodied tools are better in this regard though.
As long as you do your homework and buy air tools for the right reasons they are a good option although I have yet to see air tools with the same grunt as big electric tools - which of course not everyone looks for.
If it were me, I would set up a couple of dedicated air tool only hoses, (not for spray painting or blowing down surfaces to be painted) and run an inline oiler with proper air tool oil so that your tools are always lubricated.
I will definitely agree that cheap air tools will last better than cheap electric tools. My die grinder was only a cheapie - $40 back in 1994 and it's still going and has done an absolute power of work.
Quite often name brand air tools come up on ebay as part of factory clearances etc.

Originally Posted by LordBug

With a simple endless air mod, you can also use your air tools anywhere you take your car:
http://www.grungle.com/endlessair.html

Had one set up on my Suzuki tray top, fantastic for on site work and pumping up tyres after 4WDing.
Kryn