The badge says Simplex Sewing Machine Company, Washington DC but tucked inconspicuously under the motor is, "Made in Occupied Japan". That places it's manufacture date between 1945 and 1952 and from some of the features, I would place it towards the end of that period.
I can't find a JA Number, but "TSM" is cast into the under side of the bed. If anyone knows what that means, please comment (Toyota Sewing Machines?) Toyota began producing 15 Class sewing machines in 1946, according to their website, so it's altogether possible that this machine was made in their factory.
Many things were wrong with this one! The only things I was surprised to find in perfect adjustment were the needlebar height and the thread gap between the shuttle driver and the shuttle. There is no shuttle cushion spring on this model, so the shuttle can become noisy fast if that gap is not correctly adjusted.
1. There is a roller in the feed dog circuit, just above the hook assembly. It was frozen and the follower was sliding, rather than rolling.
2. The upper tension was assembled incorrectly.
3. The check spring was bent totally out of shape.
4. There was so much lint packed between the rows of teeth on the feed dog that the feed dog could no longer rise high enough to feed the fabric.
5. The feed dog height was out of adjustment (possibly because of #4 above).
6. The feed dog was not centered in the slot.
7. There were several loose mechanical connections and pivot points. One in the feed dog circuit made the stitch length lever vibrate when sewing.
8. The motor was so dry, it chattered when running.
Every defect corrected just led me to another, a very fun afternoon.
I will probably never get rid of this one, no one seems to want vintage sewing machines that don't come from one of the big manufacturers - Singer, Bernina, Pfaff, Necchi, etc. but it gave me an afternoon of satisfying tinkering, I didn't have to replace any parts except the bobbin case, and I can always return it to where I got it.
