My bobbin won't catch on the bobbin winder, the metal post spins but the plastic singer style bobbin won't spin with it. What's wrong?

SOURCE: Bobbin stuck on bobbin winder, how do I get it off? it will not budge!

Is thread under bobbin? can you turn it? can you pull the thread off the bobbin and then remove it? Bobbin that comes with machine may not be right one. Right one has a light blue tint and a slightly domed top.

SOURCE: Singer Futura 350

Dear Wendy,

The E4, error message means the safety device is activated. Machine is locked up due to thread entangled with the bobbin case. Remove the needle plate and bobbin case. Check for any thread around the hook area. Also check your handwheel. It should turn freely. Good Luck

SOURCE: I have a Singer XL5000

Is your bobbin case holding in place right? See if you can jiggle it back and forth to see if it moves. If it does move, it may have unattached itself in it's inner-casing.

My bobbin case would just go back and forth in the casing. Make sure that your needle plate is inserted right, as it locks the bobbin case in. You may have to unscrew the needle plate, take out the bobbin case, place it back in - pushing it to your left as you glide the needle plate back into place. (go from front to back while inserting). It should catch your bobbin case and lock it into place. Hope this helps. If not I would suggest you take it in for repair. Good luck.

SOURCE: Singer 457 Zig Zag Sewing Machine not catching bobbin thread.

There are manuals avilable online to purchase for the singer machines, SOrry I was not able to locate a site that has them for free.
.... http://sewingonline.co.uk/singer-manuals.html

SOURCE: singer 328k bobbin winder replacement

Follow these instructions, undo the 2 screws on the right hand side plate where the balance wheel is and take the plate off, undo the screw on the chrome stop motion wheel, undo the stop motion and take it off, take off the 2 pronged washer and notice which way it goes on, not a problem if you can't remember, you should be able to pull the balance wheel back so you can get to the screws on the winder, if you can.t and if you have a problem getting the balance wheel all the way then go the very bottom of the machine and you will see 2 big holes and one of the holes will lead you to a big screw and nylon adjuster, slacken the screw and move the nylon adjust so the belt goes slack, you can not take the balance wheel all the way off to get to the screws on the winder, take the old one off and screw the new one on, whilst you have the balance wheel off it would be wise to put some thin oil on the shaft before you put the balance wheel back on, when you have the balance wheel on and the and the belt round the pulley turn the nylon adjuster so the belt is tight and tighten up the screw, put the side plate back on, put the 3 pronged washer back on, put the stop motion wheel back on and just tighten finger tight then tighten the small screw.