Sometimes, if you're working with an older sewing machine, your bobbin winder won't disengage, and the needle will go up and down while you're trying to wind a bobbin. This can be caused by 2 things. #1) you've got some old oil on the shaft inside that needs to be removed. Or #2) the ring under the bobbin winder clutch is in the wrong position. Here's how to fix it...
Here's a picture of a bobbin winder clutch. It's on the handwheel of this old Kenmore. First, loosen the small screw on the center knob. You don't have to take it all the way out, just loosen it. Then twist the center knob to the left (righty-tighty, lefty-loosey) until it comes off. This is a picture of what you'll see under the knob. Can you see the metal ring that's sitting on the center shaft? Remove it.
You may need to take the top lid and/or the side panel off to allow the handwheel to move in and out. If you're not sure you can get the belt back on correctly, you don't need to take the belt off, just loosen the outer panels so you can move the handwheel on it's shaft, like this...
Can you see how the center shaft has moved back inside, as I push the handwheel out? Use some "solvent" (WD-40) to remove the old, gummy oil on the shaft. Squirt it inside the hole and work the handwheel around until the gum is dissolved. Then wipe out as much of the solvent as you can. If you have a can of air, you can blow it out -- we use an air compressor at the shop. Also use the solvent to wipe the old oil off of the metal ring and center knob.
Put 2 drops of oil on the shaft and put the machine back together.
The metal ring under the knob will have 2 or 3 raised nubs on the inside.
The raised side of the nubs should be facing outward. Put the ring in place, with the nubs in the slots on the shaft. (Take a closer look at the second picture above.) Then screw the center knob back on and tighten the little screw. You should be able to release and re-tighten the center knob.
Run the machine and see if it's doing what it's supposed to do.
If the machine isn't working well with the ring in its current position, turn it counter-clock-wise one position. Screw the center knob back on and tighten the little screw.
That should take care of it!
Here are some pictures of "tensioners." They're a small post with a springy part. When you wind a bobbin, you need to wrap the thread all the way around the tensioner. On most machines, it makes a "figure 8" as it wraps around. If the thread doesn't go into the tensioner properly, you'll get a sloppy, loose bobbin.
My neighbor just called me to come check her sewing machine. She has a Bernina 801. Great little machine! Her complaint was that it wasn't feeding the fabric through. When I got there, here's a list of what I found.
1. The feed dog drop switch was set for "darning," but the feed dog height was also low. So we moved the switch to "sew," and raised her feed dog height.
2. The needle was in backwards. We put the needle back in the right way, with the flat side to the back.
3. The bobbin tension was way too tight, and the upper tension was set loose. So we put the upper tension on its "normal" setting, and loosened the bobbin tension. Then I did a sew off sample, and balanced the tensions by adjusting the bobbin tension.
4. When I asked for a different color thread for the top thread, she handed me some "hand quilting" thread. I told her to NEVER use "hand quilting" thread on a sewing machine. You CANNOT get a good stitch with "hand quilting" thread. And you may get a burr when it tangles and pulls the needle into the hook.
