Guys, I have developed a drill bit that will drill 36" deep in end grain in one minute flat. This drill is normally used by woodturners to drill out the center of a tall turning. However, I also have a variation that fits into a half-inch electric drill that will drill at about the same speed without the wood turning. My question is: What are the common sizes you guys normally drill? No use making a 3/4" diam drill bit if no one uses that diameter, eh?

Thanks,
James Johnson
Kerrville, TX