How do I tighten the bobbin on an old Kenmore?

Actually, if the thread on the bottom side is "loopy" that indicates a tension problem on the TOP tension disks, not the bobbin. In fact, adjusting your bobbin could make the problem worse. Without the manual, you're trying to fix something flying blind, but here are some things you can try. Remember, all adjustment you make should be in small increments.

Before you start adjusting your tension, make these checks. This is very important, even though it might seem basic.

1. Be certain your machine is threaded properly. Even folks with lots of experience can miss a thread guide. Unthread and rethread it with a fresh spool. Seriously.

2. Be sure your bobbin is properly inserted. Take it out, look it over. Is the bobbin wound evenly? Look in the case for any small thread snips or lint. Clean it out. Reinsert the bobbin and replace the bobbin case properly.

3. Make sure your needle is inserted properly. Needles have a flat side and, depending on your machine, the flat side might need to be facing the back or either side. Just look up into the shaft to see where the flat side goes.

4. Look at the top tension disks. Using a piece of soft cloth or a little brush, gently insert it between the disks and move it up and down a little to remove any lint or trapped thread snips.

After going thru these checks, get out some fabric to practice on...you'll need a couple of good size pieces. Start by sewing a full line of straight stitching. Examine it. If you still have the loops on the bottom, it's very likely your top tension is too loose.

Using the tension knob on the front of the machine, make a very small adjustment to the left, which SHOULD be tighter. I say should because machines can be different but without the manual you're experimenting. Move it a SMALL increment. Now, sew a line again. Carefully examine the new line...are the loops still there? Are they same, or better? Your answer will tell you if you need to adjust the tension knob more.

Each time you have adjusted, sew a line of stitching. I cannot emphasize enough that you should only make small adjustments to correct your stitch, but if it's way out of whack, it might take several small adjustments to get you back to normal.

If after what seems like an eternity of changes, you still don't have a balanced stitch, leave your machine. Don't even look at it for a few hours, maybe a day or so. Then go back and try again. It could be you are tired, frustrated or distracted. You can try again tomorrow. If you have the same result after that try, you may need to have the machine serviced. My mother had an old Kenmore where the tension went out and nothing we did could make the machine retain the proper tension. She had to have it professionally repaired.

Just as an FYI, you can test your bobbin just to confirm the tension is ok there (but I don't think that is your problem in this instance). Manufacturers tend to not want you to mess with bobbin tension so it's not as easy to adjust as the top tension.

1. Take out your bobbin case and dangle the bobbin and case by the thread, like a spider from a web. It should hold. If it doesn't you can make a VERY SLIGHT adjustment to a tiny little screw inside the case to tighten it.

2. If it holds, give the thread a small jerk - the case should drop as some thread releases. If it doesn't the tension is too high and you can make a VERY SLIGHT adjustment to the screw in the opposite direction to loosen (usually counterclockwise).

You need to have patience when troubleshooting this sort of issue, but you can do it as long as there is nothing broken in the machine. Also, if you haven't cleaned the machine in a long time, now is a great time to take care of that.

Good luck!