The Weapon Keensmith is one who has always wondered how one can make a sword, mace, crossbow, catapult etc more effective at fighting. Thought the keensmith's travels they have observed and deduced how to accomplish this.  Wheather it is sharpening a sword a little extra, tweaking a the tension on a catapult, adjusting the fletching on an arrow ETC. This feat temporarily improves gives a +1 to damage and hit, also critical threat range is doubled.  This temporary nonmagical buff expires the first time a weapon/ munition is used. The keensmith must pass a craft check DC 13 per weapon/munition to add said buff.  6 weapons / munition can be buffed per long rest or  2 per short rest.