I have improved my tools. Maybe that is the problem?
-or-
I think you guys pushed an old bug with your last patch? Someone is working with old code. Get it together.
Man I know this is an old thread, but I found that old bug too. If you don’t have enough materials to do a full repair it takes the whole stack even if you only need a few. 10 % durability repair for an iron pick ate up a whole stack of 10 iron bars. If you have 15 iron bars or more it will repair the item only using what materials are needed.