try twisting on your sewing machine....I knot the middle of my 'strands to be twisted' or if doing several colors, knot the ends of the 'strands to be twisted' around a bobbin, place on bobbin winder, loosen the clutch on your wheel, and press the food feed while backing your hand away from the machine...if you need an especially long pc, then you need a friend to ride the foot feed while you back away across the room. Works great, fast and I already own it.
I ply large amounts of yarn and although a sewing machine bobbin winder will nicely do small amounts it doesn't work very well for my projects. I ply the large amounts using a spinning wheel but I do have a hand-cranked twister for small amounts. I was just thinking that an electric motor sounded like something I'd just have to buy...lol