Be sure to read the "Handy Tip"
I love this tool. However, my first one didn't come with instructions. The "Handy Tip" from Artbeads.com is a must read. To maintain the grit on the drill bit be sure to use water to lubricate the tip. I had mine for many years (8+) before I ruined the tip drilling stone without water. Second drill is sharp as ever after 5 years. My third purchase is a gift for my niece. (And I still have found uses for the first "ruined" drill on soft material.)
Geat tool in the beginning...
Then it starts to lose it's grit. I have used this many times to ream out beads. But now it's useless to me. The little files have lost their grit. I think the other tool, TOOL-113, would be a much better one because you have more choices to work with. I plan on purchasing one as soon as they come back in stock.
This bead reamer with diamond-dust coated tips works very well..using it, of course, with water as you're drilling. It would be nice if there was an even SMALLER drill tip included. Overall it's an excellent tool to have on hand if you're stringing beads with unpredictable hole sizes.
It is the best I have benn able to buy to enlarge my pearls, at a very good price.