On any given day, we receive calls from customers asking which is the best “brand” of air tool. This is almost always a loaded question and rather than engage them in the Ford versus Chevy debate, further questioning usually reveals dissatisfaction with the performance of one of their tools. While in almost all cases, industrial production grade air tools are going to provide better performance than an automotive / maintenance style tool, there are some sure fire ways to ensure optimal performance regardless of the quality of the tool selected. In this article we will focus on the two most important factors in air tool performance, these being pressure and flow.
Proper Air Pressure (PSI) - The vast majority of air tools on the market are designed to run on 90 pounds per square inch of pressure, commonly known as PSI. The misconception is that a 2-1/2″ drive impact wrench requires more air pressure than a small right angle die grinder. The reality is that both of these tools are designed to run optimally on the industry standard 90 PSI. Exceeding the manufacturers recommended air pressure can actually damage components, shortening tool life, and creating a potentially dangerous situation by compromising the burr, wheel, or other accessory in use. To be certain that you are getting 90 PSI of pressure when the tool is running; use an air regulator to gauge the pressure while the tool is wide open. If the needle reads 90 PSI when the throttle of the tool is closed, but dips below that when the tool is engaged; you need more pressure. Again, most air tools are designed to run at 90 PSI and will under-perform if under pressurized.
Air Flow (CFM) - What varies widely from tool to tool is the required air flow rate which is measured in cubic feet per minute or more commonly CFM. Before selecting an air tool for any application, be sure that your air compressor can generate the necessary CFM. As a very generalized rule of thumb you can conclude that for every one horse power that your compressor puts out, you will receive 3 to 4 CFM. To put it in perspective, a small right angle die grinder uses about 25 CFM while a 1″ impact wrench requires 60 CFM. In addition to verifying that your compressor has the guts to power the tool in question, make sure you aren’t starving the tool by restricting air flow through the use of a small diameter air hose. Never use reducers to adapt a 3/8″ NPT or 1/2″ NPT to a 1/4″ air line. In fact, if you can avoid it, try not using 1/4″ air lines at all. Free unrestricted air flow is paramount to maximizing air tool performance and it’s better to error on the side of too large a hose rather than choke the tool. Nothing will sabotage your project faster than an under-powered tool.
In the next installment of this series we will look at why every air tool deserves to be paired with a good filter regulator lubricator.
Thanks for reading…