Singer-Inspiration 4220/4228 New Machine- bobbin not fitting in casing tightly, keeps coming out. Also when the needle comes down in it hitting the metal cylinder that the bobbin sits on. The diagram in the instruction book doesn't show me how it's supposed to go. Please help, I don't have a service place around me.

Send this machine back where it came from! machine. You have described a timing problem which you can not and should not need to do.
Change the needle first and test it to be sure the needle still hits on the hook. If it does,follow the above instructions. If it no longer hits then it's possible it is not as serious as I first thought.I'm not sure if the bobbin keeps coming out or the bobbin case(the plastic part the bobbin sits in) comes out.If it is just the bobbin, insert the bobbin in the case and pull on the thread. The bobbin should turn COUNTERCLOCKWISE. If it turns the other way, turn it upside down and try it again.
If it is the bobbincase,then Remove the needle plate and take the bobbin case completely out. On this machine there is a small lever which holds the bobbin case in position. Looking down on the bobbin case the lever is located at about 11 o'clock and has a small slot in it. It is also probably spring loaded which means it is not easy to turn without a small screwdriver. Insert the screwdriver in the slot and turn it to the left. Lift out the bobbin case and Carefully examine it for any nicks, scratches or rough spots. If you find any, they will need to be removed with an emery stick and or a sharpening stone. Buff with a very fine steel wool for total smoothness.
To replace the bobbin case use the screwdriver to open and hold the lever open while you insert the case back in. The straight part of the case will be on the right and you need to place the case so that the circular part rides on the slight grove in the hook.(The metal thing it sits on). Once you have it in place you can release the lever you've been holding open . It should fit over the edge of the bobbin case and not allow it to come out. Rethread the machine and turn it by hand a few times to see that it is working properly. Good luck!!!
sewman7

This is a very common problem with this modle. Will keep happening over and over and over. In most cases it has to do with the needle, they are cheap and you should change them often...the other thing you can do if you are stuck with the machine is to keep an ear out you can hear it about to happen usually when you really get going fast on the machine with a thick material if you learn to listen for it you will catch it before it gets bad enough to pop the bobbin case out. Start with changing the neeld or using the right needle for the job.