Like I say I'm not somehow against photos with less-than-perfect sharpness, but sometimes I may want a pinhole photo that's as sharp as possible and other times one that's fuzzier than it has to be. Recently I took the camera described in this thread and just drilled the hole out to 1mm without any deburring or anything just because I wanted a rather fuzzy photo and could use the extra speed in late daytime sunlight given that I was using 100 ISO film. (Arguably I should have just replaced the previous one with another one rather than destroy it but I'm intending to make a better pinhole and change the focal length after that anyway. And I was kind of in a hurry at the time.)
Jim: True enough. Until recently I've just wanted common stuff and Lowes has been a little more convenient to get to, but I'm going to go check out this locally owned independent hardware store and then probably the local Ace franchise. I need to get some varying grades of "jeweler's rouge" type compound for something else anyway.
Just to play with different ways of doing things, I ordered some inexpensive little tiny drill bits, the smallest of which is 0.33mm/0.013". I put the dremel in a drill press attachment, put the bit in the thing, and tried drilling some holes in some scraps of soda can aluminum just to see what would happen. Amazingly the bit didn't break and the holes it made looks pretty good (Aside from the burrs and thickness of course). Then I found out that my new dremel had started running at full 35,000RPM speed no matter what I set the speed control to so I'm having to send it back for a replacement. Anyway, due to the bit wobbling I'm betting that whatever holes it drilled aren't really 0.33mm but it worked better than I thought. I'll probably still just use a needle "lathed" against a grindstone to the proper diameter along with the dimple sand method, though I might see what i can do using some little tiny fine-grain grinding wheels or something.
Oh yea, did I mention that I like playing with tools, technical challenges, and inventing my own processes for things? Most of this tinkering has more to do with that than trying to get the ultimate tack-sharp images.