Chris,
The owners manual is date coded: 6-53. So I'd say mid 50s.
It is the only Kenmore I have that uses this odd needle. The needle point looks like the Singer 206-13 needle. It has a very short point below the eye, just like the 206-13. So it's not only the odd length that causes the problems, but the short point too.
I have a 1930s Kenmore 117-812 made by White. Uses 15x1 needles. Sews good and will be running when I'm long gone. Also have a 158-13470 from the 70s that uses 15x1 needles and it's one of the best machines we have. Just got a 158-523 that also uses 15x1s and it is coming right along. Got some pieces to get freed up, but it sews nicely. Joe
Joe, thanks for this information. I'm guessing neither of mine are an experimental model ~ hoping so anyway ~ and I'm also guessing one dates from the 50s, maybe earlier, and the other is an unknown which also needs to be looked at and worked on. Here's to hoping both of mine require 15X1 needles. Thanks for sharing your knowledge with all of us on the board.
Chris