The Weapon Keensmith is one who has always wondered how one can make weapons more effective in combat. 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 gives a +1 to damage and to hit, also the critical threat range is doubled.  (The effect does not stack when ammo and ranged weapons are both used together) This temporary nonmagical buff expires the first time a weapon/ munition is used. The keensmith must pass a craft check with character proficiency bonus DC 13 per weapon/munition to add this buff.  6 weapons / munitions can be buffed per long rest or  2 per short rest. The effect expires in 24 hours.