Singer tension really loose
 

Can anyone help? I have a Singer 403 and it sews beautifully when set, but the tension knob is very loose and when I am sewing the vibration of the machine moves the dial so that the dial moves to 1 and I end up with birds nests on bottom. Is there anyway to tighten this?

Have you tried taking apart the tensioner and cleaning it and reassembling it?

The 403 is my machine of choice... Once you get it straightened out you will love it. Some times your owners manual will have info how to do your tension. If not, there is a repair manual on line and it is free. Here are some links.
The 401 info will do for this.
http://www.ismacs.net/singer_sewing_...ng-machine.pdf

I like to print them out and scribble on them you can make extra

401a repair manual - you have to scroll down 125 pages more or less to get to the 401
http://parts.singerco.com/IPsvcManuals/306W25.pdf

Since it has been coming off - it probably isn't put on right - you will need to read the instructions very carefully - you can't simply undo and fix this one. I wonder if the set screw on the side of the machine is loose or missing? I do know the directions are pretty good and helped me fix more than one that came with missing parts.

http://www.quiltingboard.com/vintage...s-t170748.html Here is one I made a week or so ago

Thanks for the link. I put it on a disk for future use. I have a 403 but it doesn't have the tension problem Cheryl222 is experiencing. My problem was with the bobbin case but I have Featherweight 221 info and it worked on the 403 bobbin case so it's working just fine. It sure helps to have this kind of info on any vintage machine.