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Grex air-powered die grinder
There are two aspects of this review I feel were overlooked: where does the exhaust air come out, and how hot does this unit get if you use it for an extended period of time when doing heavy carving. One design aspect of any air tool, but especially an air grinder, is to inspect where the exhaust air comes out and in which direction. At first this may sound odd, but considering that you need to add oil into the air supply on a very regular basis, it will eventually blow out the exhaust. Typically this oil will be in the form of extremely fine droplets which if exhausted anywhere near the “business end” of the tool (near the cutter/sander) will possibly stain or contaminate some porous materials like wood. This can lead to problems with subsequent coats of paint, particularly any water based finishes. I look for tools that exhaust away from the workpiece. Another aspect which can be troublesome if you are going to use any tool hard and for an extended period of time is how much heat it builds while it is tightly clenched in your hand. Typically electric tools are the worst and air tools are better (since they have natural air cooling). Typically but not always. Some smaller high speed tools such as air grinders will build up more heat in their bearings than the air flow will reduce, eventually the tool body simply gets too hot to hold comfortably. A tool with a metal body will conduct the bearing heat faster to your hands than a plastic or insulated tool body. Of course this doesn’t happen in the first minute or two, but if you are trying to carve model figures from solid wood and working for 20, 30 minutes or longer, then problems can show up. Information like this in the review would help readers to be better prepared in making buying decisions.