I have been using scissors for 35 years and have tried them all. You try to tighten that center screw then for some reason the jaws keep tightening on their own, even if you try to loosen the screws they keep tightening with your use so I don't mess with them because I don't have time keep loosening or tightening the screw, so I just throw it away. done, but for now these scissors seem acceptable. I bought them a month ago and they look like they could take the punishment of a professional metal worker. 8 hours a day 40 hours a week. and they exist. they are worth it Clauss 18423 Titanium Bond Airplane Scissors - Left Clauss 18430 Titanium Bond Airplane Scissors - Straight is mainly used for workshop work. Aviation scissors Clauss 18421 with titanium bond for sheets with right cut. Both red and green colors are used on fields.