I like a particular brand of v-neck tee-shirts that run a little long, and I hem them myself. First, I baste the bottom to the length desired. {I have a serger w/cover stitch, but I don't use it.} Instead, I prefer to do them on a regular straight-stitch machine, a double needle and wooly nylon in the bobbin. Just remember the wooly nylon has to be hand-wound onto the bobbin. Most sewing machine manuals have directions to use a twin/double needle. With two threads on top and wooly nylon in the bobbin, sew a seam from the top side and then trim as close to the hem as possible. I do sweat shirts in the same manner, as well. HTH, Emily