Do two sports make a worst?

Worsted that is.

I'm a stripe away from finishing the front of the bias top and it looks like I'm going to have some left over yarn. Now if i double-strand the Microspun (sport weight) do I get what would be a worsted weight yarn? Yes, I know I should do a swatch, but I figure I could ask first and see if I'm way off. I figure if it works out, then I could make a boobholder with the rest of the yarn.

Oh and where does "DK" yarn fit into all this? I have a bunch of skeins that are dk, is this close to worsted? I've tried looking all this stuff up, but the whole stitch count but needle size changing is quite annoying. There should be a standard needle size we measure to so that a fingering yarn would have say 30 stitches or something but then a bulky yarn on same needles would have 1. That way you just look at the stitch number.