Thanks for the info everyone.
I have heard that Cobalt bits can be brittle and considering how expensive they are, I think I will just go with another HSS set. Possibly TiN if I see a great deal. Like Stuey said, I can always pick up specific sizes in Cobalt for hard metal work.
Any thoughts on brand? I will spend whatever is necessary to get a quality set. I will be using these a lot.
I have seen the HF step bits in newspaper ads and have considered trying them. They are really cheap so I can always give them a shot and if they don't last get something better. Just curious, what is a good price for a Unibit 3 pc. set? $45-50?
I actually interviewed someone from Vermont America for a very indepth story on drill bits a few years ago.
REAL TiN bits are coated with what amounts to a dry film lubricant. The friction of a drill bit isn't limited to the cutting area on the flutes. In fact, there shouldn't be friction there--they should be cutting. The sides of the hole are what creates the heat, and will contribute to wearing out a bit--as the temp in the whole tip of the bit increases due to friction on the sides of the flutes, the temper of the cutting edges will go away.
Cobalt bits are steel with... well, cobalt in them. The bits are very hard, and will cut through very hard materials, but they are brittle--they can't take any kind of side load or they'll snap. No hand drilling--machine tools only.
As a really cheesy experiment, I put 1/2-inch HSS Cobalt bits through my chop saw and timed how long it took to grind through them: it took almost twice as long to go through the cobalt bit.
Imported TiN "coated" bits are really just gold colored... there's no coating on them.
I can't remember if the TiN (the real one) makes the bits tougher or not. But the Vermont America engineer told me that while the bits cost almost twice as much as HSS bits, they get 3 to 4 times the number of holes out of them before the cutting tip goes away.
So that's my contribution there.
There was a post about a year ago about the Harbor Freight step drills, and they were overwhelmingly popular. I got a set, and am very happy with them.