CFM - My compressor has a CFM rating of .39. And I know I said I wasn't going to get technical, but CFM (amount of air flow) is an important number to look at when shopping for an air compressor. Every air tool requires a certain amount of CFM, or amount of air flow, to operate. The greater the CFM, the more air the tool uses. So you need an air compressor that will produce more CFM than your most powerful tool requires. And I have a handy chart to show tools and CFM:
Brad Nailer: 0.3 CFM Ratchet: 2-5CFM
Sander: 11-13 CFM Spray Gun: 2-4 CFM
Impact Wrench: 4-5 CFM Die Grinder: 4-6 CFM
My .39 is enough to use my nailer; however, it wouldn't be enough for a sander. I would need a larger compressor for the higher CFM tools. Also, some people look at the PSI rating only. Well, most air tools require 90 PSI to operate and the majority of air compressors produce at least 90 PSI. So you should be good here. Just make sure that the compressor has a high enough CFM.
Pressure Regulator Knob - Adjust this knob to regulate the amount of air going to the tool. Turn to the right for more, and to the left for less. When turning on the air compressor, make sure this knob is all the way to the left (closed) so the tank can fill up. You can see what the pressure is on the outlet psi gauge.
Outlet PSI Gauge - This gauge shows the amount of air going to the tool. For nailing and stapling, pressure should be between 90 psi and 100 psi. You can increase or decrease the psi with the pressure regulator knob.
Tool Holder - This handy hook is for storing the nailer.
Release Valve - Pull on the release valve to drain the air from the tank.
On/Off - The power switch.
Gauge - Nail guns vary in the length and gauge (thickness) of nails they can drive. I have a finish nailer that can only do small nails and staples. The smallest size of fasteners are normally 24 to 22 gauge and generally have no head. They are used for attaching beadings, mouldings, etc. The next size up is the 18 gauge, often referred to as a "brad nail". These fastenings are used in the same way as the smaller fastenings; however, they usually have a head which leads to some hole filling. The next sizes are 16 and 15 gauge, or "finish nails". They are used in nailing softwood and MDF trim (such as baseboards) where the holes are filled and painted. The big brother to my finish nailer is a framing nailer which uses the heavy-duty big nails.