All I know about it is that is has 'SEAMSTRESS' on the arm and it was made by the National Sewingmachine Company. I know how to fill the long bobbin, but haven't a clue how to thread the machine. When the cord is plugged in and the machine turned on, the needle does go up and down just fine, but need to know how to thread it before I can see how the stitches are. I can not find either a picture of one like it, nor any place that has a booklet that tells how to take care of it. Sure do love the looks of it. I'd like to paint the case, but is seems to be paper covered wood - a very sturdy case.

Why not just try threading it in different ways til you see what works?

Ditto!! It should have the arm going up and down and a tension wheel, try putting the thread through in the same order as any other machine. Trial and error until it works. Good luck.

Take it to a sewing machine dealer and see if they can help.

Ask the Board - Lostn51 - Billy has a lot of knowledge on various vintage machines. Or post a picture on the Vintage machine blog... since Billy has been sick, others on the Vintage blog may be able to help you out rather than folks on the MAIN blog.

This one looks like one of the Singer clones made in Japan. Look around the machine and see if you can find a serial number and check the Singer website. It has lists of clones serial numbers if they were made with the Singer blueprints so it might give you something to work with.

That machine has the leaf spring tension. It is definitely not a Singer clone, they had the round dial tension on the far left side (end??) Maybe you can Google "Threading a leaf spring sewing machine"

That is an interesting machine--it looks kind of 40s or 50s to me with the body styling, but then it has the leaf tension on top and the long bobbins, which seem like features common to older machines.

No clue how to thread it though.

http://www.ismacs.net/national/home.html

Hope you can find their phone number through the website listed above.
JOY