Hi I have a union special 39500. It has a curved needle. I can not figure out how to change the needle. There is a small hole that that needle bumps against on the screw. Does the needle go in there? I have tried many times putting it in the hole or either putting in this ridge that is there and either the needle over shoots the hole it is suppose to go in or it is too far to the left. Please if anyone know if they could let me know. Thanks! Jim