First off, welcome to our humble little home on the 'net...
 | Quote: |  | | |  | Originally Posted by Jordan.Misner |  | | | | | | | | | I hear you guys saying piece #542, #502, et cetera -- none of that means anything... | |  | |  | |
The store where you bought the Dremel should also sell individual bits, along with the cutoff wheels and such. At the top of each pacage there should be a number, designating which bit is in the package. THAT's what people are talking about when they talk about cutoff wheel #426, or diamond-tip engraving bit #582 (just for example, probably not the righht numbers anyways...), as seen
HERE
As far as the cutoff wheels, that's what their primary use is, cutting stuff off. The stock ones are good for general purpose cutting, but the reinforced ones (#426, I think) are the best bang or the buck if you're going to be doing a lot of cutting. You CAN use them to do what you're talking about, but if you don't have any wheels that are already the right size, go ahead and get used to being saddened. Unless you start the slot with the cutoff wheels, and then use a reciprocating saw with a metal bit to finish the line, you're going to have to save the worn-down cutoff wheels and use them instead.
Your level of ability is only limited by your imagination, and your willingness to try and fail in order to learn to do it better...