My Unibits last a long time by buying a couple of 1/4" metal drill bits. I make a pilot with a 1/4" drill bit and then drill with the unibit. I also use a small drill bit when trying to make bigger holes in metal with bigger drill bits. This saves the point. By the time they go bad, I usually just toss them. They are very expensive but I got the most out of them by using my method. I dont have any suggestions for sharpening.
I usually sharpen them on a grinding wheel... You have to get the relief correct or the bit will walk while trying to start a hole. I compare the bit that I am sharpening with a known good bit. I admit that it is some what hit or miss, but I figure that the bit is not working right, so I have nothing to loose.
This idea occurred to me several months ago too. So I brought home my near-the-end-of-it's-life-cycle-unibit and fired up the old dremel. I did the best I could to keep the edges straight, but without some sort of a guide it's quite hard to do. Also where the bit steps to a larger diameter it's difficult to sharpen the edges while maintaining the proper angle of the step...difficult to describe...difficulter to do. All in all it was not an easy task. The results speak for themselves: The bit now works fantastically well! (for making holes in drywall.) And it was nice to finally use a sharp unibit...when I picked up a replacement. I was doing some work in a machine shop so I asked if they would be able to sharpen a unibit for me. Apparently it would take about 2 hours to do and it would cost more than a new bit. I agree with Gibbons and make a pilot hole first and then switch to the unibit. It prolongs the life of the tip at least. I also have a plastic case from a short auger bit, about 3" or 4" long that I store my unibit inside. Then the bit's cutting edges aren't bouncing around hitting stuff and being dulled in my tool box.
Ok I was reading electrical contractor magazine and found an interesting product. Finally someone came up with nice solution to an expensive problem. Let me know what you think and if anyone is going to try them. Brian
Run a small diamond lap along the flat faces, as Reno says, don't touch the diameter. This is a technique I use to keep router bits sharp. Don't overdo it, a diamond lap will remove metal very quickly. Sharpen little and often, as a keen edge lasts longer than a blunt one. A badly blunted cutter may not be revivable. I'm not sure what the 'titanium' coating is supposed to do, apart from giving the marketing departments a bit of snake oil!