Actually, see the one on the left? I bought one just like that around 40 years ago and it only recently decided to no longer workCheap chinese steel, thats why.
by the time that you get them home in the bag that they gave you, they are already broken.....into smaller BITS.FYI: China is using a new element to make the tools, it's called Chinesium.
Chinesium drill bits are to be used only on warm chocolate or unrefrigerated margarine.