How do I put a bobbin holder securely back in a singer 4210?

SOURCE: Installing the hook and bobbin assembly.

The plastic bobbin case should sit on top of the raceway, it should slot in quite easily, once the bobbin case is in put the small metal clip at the top over to hold it in place.

SOURCE: can't put the plastic bobbin holder back into position

make sure the needle is all the way up and the bobbin is in the case the right way. check to be sure there is no lint or dirt impeding the case. you may have to take out the piece the case fits into to do this. i have found this to be the problem more times than not.

SOURCE: The bobbin case on my Singer Inspiration 4210

From what I gather on other sites, your thread has to be threaded under tension.... You have to make sure you hear a click when your bringing your thread down to the bottom of the "arm". Also, I thought the bobbin case was rather loosely held in its place, I adjusted this by unscrewing the black plate and moving it over just a smidge. The bobbin is supposed to have some wiggle room, but it kept popping up and making the tiny adjustment seems to have done the trick....for now...

SOURCE: The bobbin case on my Singer Inspiration 4210

unscrew the black plate that holds in the bobbin case and move it over to the left just a little bit, but make sure there is still clearance between the lower right corner of the case and the plate. The case should be able to wiggle a little, but not so loose it can pop out..