Originally Posted by thepolyparrot
Do you have a presser foot on?
If you don't have the thumb screw on the presser foot at the moment, this little screw probably goes on the face plate and the thumbscrew that's on there now goes on the presser foot.
I'm out of ideas after that - and I just finished re-assembling a 15, today. Shows you how short my memory is! ;)
That is the faceplate screw that is loose. I have never seen a 15 with a thumb screw on the faceplate.
Also if it was the stop motion knob screw it would have a shank on it.
Billy