Singer 28 bobbin winder spring
I am restoring a 1908 Singer 28K and all is now working well apart from one part. The bobbin winder has a Spring action arm with a small pull knob that holds the bobbin in place. This is the arm at the top left opposite the cupped end above the cam. My problem is the Spring is weak/broken and will not hold the bobbin in place for winding without pushing on the end though out winding.
It is not obvious how to access the Spring. Is the knob screwed or pressed onto the shaft? I guess any small Spring of the right length could be used as a replacement but I need to get to the old one first!
Any help with this would be much appreciated.