Help with tension
 

My boyfriend's sister gave me her sewing machine that she said she used maybe once a few years ago. I left it at my boyfriend's so that I could see both at my place and his. It is a brother cs6000i. The tension is off and I don't know how to fix it. The blue is the top thread and the tan is the bottom. I can pull the blue thread at the end of my scrap fabric and it pulls all the way out. I've loosened the top tension to 1 and it does the same thing. I've turned the top tension up to 4.5 and while I can't pull the top thread out, the bottom thread still shows through. It's on the straight stitch setting. Any suggestions???

I think your problem is with the bottom tension. If you look at the bobbin holder, you will see a very very tiny screw just below the slot where the bobbin thread comes out of the holder. You can tighten the bobbin tension by turning that tiny screw to the right. But be very very careful. Start with just 1/8-1/4 of a turn. See if that makes a difference. BTW I use my DH's computer screwdriver set to do this. They seem to be the only ones small enough to fit.

Here's all you need to know about tension.

https://www.threadsmagazine.com/2008...thread-tension

I don't know about your machine, but I have a Baby Lock that has specific instructions in the manual to not adjust the bobbin tension on the special bobbin case. I think that's unusual, however, and I have made that very slight adjustment on a few machines. It never seems to help me, however. Sometimes what looks like a problem with the lower tension is actually caused by the thread not getting engaged properly in the upper tension. Sometimes there's some thread or fuzz caught in it. Try rethreading, and always cut the upper thread at the top and pull the piece out from below. You may need to take the machine to a shop to clean out the upper tension area, which - if that's all it needs - is not a very costly or time consuming fix. I hate that the tension disks are in where we can't see or reach them on modern machines.

If you have the instruction manual it will show you how to adjust the bottom tension. Taking a picture of the setting before adjusting is a good idea.

I do hope you've solved your problem. my bobbin thread is messing up for the second time. grrr. i hate changing anything. usually do no have to.

It looks to me as if your fabric is loosely woven. That could be a problem. Can I suggest you use a finer thread and then see if you need to change your tension?

I would take the machine to get it serviced. By just sitting around, who know how much dust and/or moisture has settled in the gears. Good luck.

Have you made sure the thread is coming off the bobbin in the correct direction? Some bobbins need to rotate clockwise and some counterclockwise.