Kelsie here is the difference between the one o'clock and the eleven o'clock... you have to look to where the arm is pointing
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Janey you are right, my 15k88 and my 15b both have the 11 o'clock bobbin case but my Omnia M12 has the 1 o'clock case (which is now the standard bobbin case found on most modern machines)
Kelsie, I found this video about the Singer 237: at about 2min, you'll see the lady remove the bobbin case and it a 1 o'clock, like the one you showed on your pictures
https://www.youtube.com/watch?v=QKEtRJ61IN0
EDIT to add: On his website, Thierry Hacquard confirms that the 237 has an oscillating hook system which adds up to the rest of your parts! (I put the link in case you are comfortable reading French
)
http://t.hacquard.free.fr/site4/237.html