We simply cannot overstate the importance of wearing high quality safety glasses when performing any machining operation. Regular glasses are not designed to withstand the impact of a flung piece of metal and can shatter, causing even more damage. Any time you are working with a cutting tool that is tearing hot bits of metal from a part, whether it is on the lathe or the mill, you should be wearing eye protection. Even when no tools are running, they help keep you from inadvertently wiping your eye with chips on your hand. These high quality glasses are light, comfortable, produce minimum optical distortion and wrap around the end to protect your eyes fully. No one who has ever had a piece of a shattered tool bounce off their glasses or been to the doctor to have a rusting chip removed from their eyeball will ever turn on a machine without eye protection in place. Neither should you. As it says at the beginning of every one of our pages of instruction: "Foresight is better than no sight!"