A drilled hole will be accurate to about two thousandths of an inch in diameter. Use a reamer if greater precision is required. A reamer looks like a drill bit but it has no point, so it's not useful for starting holes. The reamer is meant to be put into a hole that is only slightly smaller than the body of the reamer, and as the reamer turns it will scrape a small amount of material off the sides of the hole, making the hole a precise size.

Using a reamer

A drill press is a fairly robust machine but it does have its limitations. You shouldn't drill holes larger than about 1 1/2 inches in diameter. In aluminum, you can drill a little larger -- around 2 inches. Going beyond that risks damaging the machine.

Although the drill press looks like an arbor press, it shouldn't be used in the same way. Arbor presses are designed for dealing with large loads, and using the drill press as one might damage the quill feed.

The drill press also looks like it could work as a milling machine, but it is a poor substitute. Both have quills, but the quill on a drill press isn't designed to deal with the sideway forces that milling creates. If you were to use a drill press as a milling machine, and it would look to be cutting as a milling machine does, but the cutting tool would bounce around too much, giving you an unacceptable finish.