That's weird, I was thinking 3 and wrote 2. In my defense I said that when you make 2 bronze ignots (3 copper, 1 tin) you can crit to make 6.^^
As for the bonus crit item I bought one off the AH and gave it a try. You are correct, it displays 50% crit chance. I do not understand this though,as it says I have a base 5% and the item ups it by +44%.
-If the game added the percentages directly and simultneously then it'd be 49% crit chance
-If the game had a chance for one crit to occur, and if that failed then the other, then it would be a [1-(1-.5)(1-.44)]=46.8% crit chance
Something is being displayed incorrectly. I doubt the crafting system is so complicated that there is a hidden factor, rather that something is being rounded up. However with normal iron tools (+2%) it displays a 51% chance to crit. With crit iron tools (+4%) it displays a 53% chance to crit.