Welcome sew4dancers.
The rufflers are great fun - and - they seem to multiply (just like vintage/antique machines) LOL
I see you have a manual - which can be extremely helpful. Some of the manuals will show how and where to adjust if the bobbin isn't winding correctly. It would be helpful to know if your machine is a long or round bobbin. It would also be helpful to see how you have it threaded to wind the bobbin.
Since I don't have a Free Westinghouse of either bobbin type, I'm not sure what you are asking about the needle. Is it that you are trying to use 15x1 rather than the size that was originally intended for the machine?
Janey - Neat people never make the exciting discoveries I do.