Cari, you were right!
 

I've been dealing with random thread nests on my 401a. I've cleaned it. I took a brush to the bobbin area and removed all the lint. I removed the bobbin case and cleaned it and checked for burrs. I removed the bottom cover and blew out everything with the air compressor. I thought it was clean.

Cari said the bobbin race might be dirty, so I did it all again. I had trouble putting the bobbin case back in, so went to youtube to see what I was missing in getting that thing back in. I pulled up a tutorial with some woman cleaning a 401 bobbin race with q-tips with a drop of sewing machine oil on it. So I tried it.

This is what I cleaned out of that bobbin race. Needless to say, I haven't had anymore trouble with thread nests.

bkay
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Yeah, sometimes you even have to take a pin to that groove in the track. It can be hard to see all the packed in lint. Glad you figured it out!

Cari

I just remove it then clean the rest of it.

YAY. well done bkay and Cari

I need a "like" button! Cari is so generous with her experience with the older machines. And I learn something every time she shares that knowledge with another QB quilter with problems.

Awe, thanks Barb but everything I know has been learned here and on other groups/forums from people who know much more than I do. Sharing and helping is how I pay it forward.

Cari

Do you mean to remove the bobbin race and clean it? If so, I'll have to figure that one out.

bkay

Removing the bobbin race is the only way to be sure it is clean and will run smooth. I routinely take them out as I clean any machine with a drop in bobbin. When I’m sewing I often have to stop and take it out to clean. The 15 type bobbins come out to clean but a lot of times they don’t accumulate as fast as the drop in type.

They are very easy to take out. Getting them back in is another story. The fork goes around the little protrusion thingy.