Any machine that does a zig zag stitch and has a foot with a big enough hole to accomadate two needles should work. If you only have one thread pin you could set up another spool of thread on a stand behind the machine take the plastic lid off of a small butter tub etc. poke two holes in it. One to put your machine's spool pin through and the other to thread the additional thread through. The tricky part is threading both threads through your machine. You can do great things with a double needle. I have a very good serger but I was not interested in the "chain stitch" that I could have gotten for more money. I can imitate the same stitch with my regular machine and a double needle. The big difference is that I don't have to worry about pulling a thread and having the whole thing unravel. I am sure you have had that happen on a knit garmet with a chain stitch hem. It also allows you to do beautiful pintucks which are very decorative.