I have a 306 W. You may want to try this...In the hand wheel there is a large silver "inner" wheel. Hold the outer wheel and tighten the inner "wheel". When filling bobbins on the 306 W this "inner" wheel or large screw gets loosened . This will allow the bobbin to fill with out the needle being engaged.
Needles for this machine can be tough to come by as it takes a shorter needle. If you need any info on the Shmetz number that fits just send me a PM.
The 306W is areal work horse of a machine , Mine was my mom's and saw decades of HARD use before I got it. Mine still runs like a champ and can tackle fabric that my other machine can't.
I have the original manual for this machine if you need any assitance.
Last edited by Lori S; 12-15-2012 at 07:54 AM.