Karl, there is a difference in the brands and quality of these index drill bits, I have two different brands. One has black drill bits and I purchased them at Princess Tools here in Canada, Princess tools is very much like a Harbor Freight retailer. I'm not sure of the brand, there's twenty bits to the small container #'s 61-80. The other brand I have is called Hawk, they are a silver colored bit, and they are much stronger than the other brand. I'm not to sure of where I purchased them, but, they must have been at a good price seeing as how I bought 4 sets. I use a full size drill press on low speed, with the regular drill press chuck and if I break a bit, it's usually because of something I did wrong. These bits are so small, that I don't think they should be used in a hand drill. Use a drill press, or, use a dremel type of tool that has the plunge base installed. I hardly ever break a bit, now that I no longer use a hand drill.
Len