My papaw was a boot maker and did shoe repair and saddle/leather repair for almost 63 years, I still have access to his machines. A friend asked me to stitch a separation in a breast collar, which would be no problem if I could remember how my papaw showed me to thread the machine. I have the parts manual but no diagram for threading it. I have put fresh wax in the wax pot and I think I have the top side correct but it will not pick up the bobbin thread. I am sure it is something very simple that I have overlooked. I would really appreciate anyone who could tell me what I am doing wrong.