Below you will find a picture tutorial for threading a New Home treadle sewing machine.If you've never threaded one before, the parts may look a bit foreign. You can see the names of the parts here. The names for parts shown in the manual will be capitalized.
1. Pass the thread between the Tension Spring and Cap using the slot (Thread Guide) pictured above. Unfortunately, with this type of tension mechanism, tension is not released when the presser foot is raised. As a result, the further you have threaded into the thread path, the harder it will be to pull extra thread. You may find it helpful to loosen the tension a bit using the thumbscrew (Tension Screw) you see above the first few times you thread. Otherwise, just pull extra thread length at the start of threading.
4. Pass the thread behind this loop (Staple on Face Plate). Hold the thread end in one hand, and using a pin or stiletto in the other, pull the thread through the loop, and around the hook shaped take-up lever (Hook of Take-up).
5. Lay the thread in this groove.
6. And thread the needle left to right. (The needle is inserted into the Needle Clamp flat side to the right). If you loosened the upper tension to start with, readjust it now.