I use any thread but I do mostly use connectingthreads thread. I have not had any problems but I did buy from
http://www.shop.sew-classic.com a new spool pin that has a hole in it so provide a place of you to run the thread through if you are using a cone on a cone holder. They also sell a little spring to put over the spool pin that they say makes the spool turn easier if using a normal size spool of thread. I have purchased from this store several times and am very happy with their shipping prices and fast shipping. I like that idea about the Sonic straw.