I'm assuming you meant chains for a 12" bar, so if you can't hand file the best inexpensive tool for small chains is the Stihl that kthompson mentioned.sharpen her little 12 inch Stihl chains;
Agree...I bought the Pferd version Same thing but a little less $$. I would learn to do a better job but I am just a hack and good enough is good enough. BTW, I have a buddy who is an arborist and cuts for a living. He was impresses with my little "toy".