I don't usually take the time to review a product because there are so many reviews already, but this item deserves a review. I rework carburetors for Porsche vehicles and, after machining aluminum bodies, smooth out sharp edges by hand with hand deburring tools, scrapers and files. It's quite strenuous and also a bit hard on the arms and elbows. I thought it would be worth the price to try this pencil sized grinder and despite some negative reviews I bought it. Brief History: Works like a champ! Runs smoothly and appears to be well made. I use a flow control valve to adjust the total airflow to the tool to slow it down a bit and with the carbide bit installed it makes my deburring job a lot easier! I wear hearing protection as it produces a high pitched hum which I am happy to accept to improve my performance. I have no comments on the durability or reliability of the coffee grinder. It runs smoothly and there are no crashing issues as other users have reported.