@Enterich: They should be in there, but the table assumes that class-specific items and other weapons are equally distributed when gambling, and I'm not sure if that's correct (there are 7 weapons a wizard can get but when I gathered data from gambling 1000 weapons back in May/June it actually seemed as if class-specific weapons roll twice as often, so the expected amount of blood shards would only be 50% of what it says in the table). Regardless, it's pretty low either way and I would not recommend anyone to gamble jewelry or weapons - ever. It's statistically just really really stupid.
@BadLarry68: As I've pointed out in another thread, this "I need to get a Furnace to succeed" tendency is getting a bit crazy. There are totally viable alternatives that are just slightly worse than an ancient Furnace - and an ancient Furnace is an item you might not find even if you reach paragon 1000. Really, free your mind and stop looking for this imaginary item and rather resort to other ancient and readily available alternatives. Maybe one day a Furnace will drop, maybe not. Stop worrying about it and most importantly stop believing that a Furnace will help you to magically get 5 levels higher (because it doesn't).