I just finished fixing a frozen bobbin winder for Towne Cleaners here in Fallbrook, CA and I figured I would post the solution here since the Juki DDL-8500 is a common machine. These machines, and almost every other machine needs regular maintenance to prevent parts from freezing up. Without regular lubrication, the metal parts in your sewing machine will bind up and could completely ruin your machine beyond repair. The bobbin winder is no exception to the rule. Thankfully with the DDL-8500 its very easy to keep the bobbin winder lubricated. Read below for the solution and how to keep it from freezing up and not working.
If the bobbin winder is not working on one of these machines it’s most likely because the bobbin winder has bound up due to lack of lubrication. To confirm, all you need to do is try to turn the bobbin winder manually with your hands.If the bobbin winder moves freely when you try to turn it, but it won’t properly wind bobbins, then you may need to have a service technician come look at it as there may be something more serious going on. If it doesn’t move at all then all it needs is some lubrication to get it working again. If you inspect the bobbin winder closely you will notice a small hole facing upwards to the left of where you put the bobbin. This is where you are going to add oil to get the bobbin winder moving freely again. It’s a very small hole on the shaft and you may not notice it at first if there is grease or other gunk built up so you may need to clean the bobbin winder shaft before it becomes visible. Once you’ve found the hole, you will need to clean it out if there is any buildup inside. Otherwise oil will not be able to penetrate and get where it needs to. After cleaning the buildup out, apply a few small drops of oil and try turning the bobbin winder. You will notice it loosening up little by little. Apply a few more drops of oil and keep turning the bobbin winder by hand until it turns easily. Now try to wind your bobbin and it should be working just fine!