Sewing Knotting in bobbin thread?

If the machine has been stored for ages, a tune up might be a good start.
There are tricks with a piece of tissue or light paper under the sewing at the start which some have recommended as doll sewing is fiddly stuff & can easily get pushed down through the plate with the needle rather than the needle poking through to make the stitch .
If it tangled more than at the start I'd say make sure the needle is in correctly, check the tension, & maybe refill the bobbin. But doesn't sound like that's the problem.
Have you put in a new needle so it isn't dull or the tip broken? That could make it harder to start a row of sewing.
Hmmm...trying to think what else to suggest...

 

When you start sewing, are you holding the thread ends to the back (way from you?). I know if I don't hold the threads when I start a seam on my machine it can often tangle on the underside. (My machine also likes to tangle when I use the reverse but not sure if you are using reverse as not mentioned).
Another thing is that the stitching messing up on the underside of the fabric is often caused by the upper thread so make sure you're treading the upper thread correctly, the thread is flowing smoothly and that the upper tension knob hasn't been bumped to something unsuitable.
Hmm, that's all that coming to mind at the mo

 

If you have not touched that machine but briefly in 20 years, it is long, long, long overdue for a cleaning and re-tuning. Fluff and oil build up inside, the tension sets get all wonkey (that's your tension that is giving you the knots, without seeing your knots I can't tell you if it's bobbin tension or top tension) and it needs to be seen by an expert. Ideally a sewing machine should be serviced every year. Especially if you are doing a lot of sewing on it. I do not reccommend you trying to service it yourself, or get a "handy" friend to do it...this will only end in tears and an unusable machine.

Do a websearch on "Bernina Service Near Me." You want to get a technician that is licensed to service your particular machine. They are often the same people that repair vaccuum cleaners.

 

1) Get the machine serviced.

2) Adjust the tension both on the upper thread and the bobbin case - test each adjustment on scrap fabric until you get the settings right.

3) Make sure you have the same wight of thread in the bobbin as you are using as your top thread. Sometimes something as small as using a different brand of thereead in each can throw things off with particularly temperamental machines.

4) Use a new needle (of the correct size and type for the fabric) for each new project or change your needle after each 8 hours of sewing.

5) Make sure your brand of machine doesn't require own-brand, or specific brand needles. Elna machines, for example, used to be notorious for tangling threads if you didn't use Elna own brand needles (they had a slightly different shaft length and it threw the timing out if other needles were used). I don't know if this was ever an issue with Bernina, but it's possible.

6) Hold the ends of the thread taut out the back when you start stitching.

7) Use "leaders" and "footers" when yu staart and finish stitching - this is an oold patchworker's trick whereby you use a couple of small scraps of fabric to start your line of stitching and then run the stitching straight off that onto your actual fabric, and then run off the end onto another couple of scraps (leaving that under the foot/needle as the "leader" for your next bit of stitching).
That way, any tangles that might happen at the start and/or end of your stitching line happen on the leader/footer, not on your actual work-in-progress, you can use these leaders and footers over anad over again until their too stuffed up with stitching, then start new ones.

Hope this helps

Teddy

 

If you are not holding the threads I would be more surprised if it didn't tangle.

I agree with the others, though, do give your machine an overhaul. I used to work in a sewing machines and notions shop and our repairman recommended that a machine be run at least once a month to keep it working well. These macines are made to be used, especcially the older ones.

 

Bernina (sergers at least) are very particular about tension & you may need to unthread & rethread the machine.
A service person taught me to only pull on the thread when the presser foot is up, for my Singer, as otherwise that can also upset the tension setting.
One of my many second hand machines actually has rust in the tension works which causes drag on the thread another possibility after life in a car...
Another of my machines was riding in the back of my car & toppled over. When I went to use it I had to fiddle with the whole tension dial as the fall had knocked it. Still needs to see a repairman, as it the tension now slips adjustment at the knob. But it's sewing so I've put it off. ;}

One last thought as to which end you sew & whether it tangled: are the two fabrics you are sewing the same? And it's flat, straight seams that are balking one way but not the other?

Definitely time for a needle. And a good tuneup. If you were in ny I'd recommend one of my local Bernina guys, they're as skilled at clockmakers when it comes to machines.

 

Yup, that's all tension. The closest Bernina store may be able to give you good quick tips in the meantime. It would be worth asking, I e always found sewing machine folks helpful.

 

Have you tried adjusting the tension on the bobbin case? If it's a metal case you put the bobbin into, there should be a little screw on it that you can turn (screwdriver proably came with the machine) to loosen or tighten the bobbin ttension. Experiment with altering this, and the upper thread tension in case it's just got out-of-whack while the machine wasn't being used.'

Teddy

 

{nods} Been there - Sometimes I put a tiny dab of correction fluid or nail varnish to mark a spot at the edge of the screw-head and the casing, so I can more easily count how many full (or partial) turns of the screw I've made in either direction, and be more sure of getting it back to it's starting position if adjusting it doesn't work. My needlework teacher at school thought I was being overly cautious - she just went at it with the screwdriver adjusting until it worked... Mind you, she used to freak out when I sewed over pins and I've never had a problem with doing it so each-to-their-own.

Teddy

 

It think it's a good idea to be careful about the bobbin tension.
You absolutely can adjust it yourself, but it's also completely possible to overtighten the screw and mess up the spring to a point where it need to be replaced and that's kind of an expensive part. Same mechanic as I mentioned before recomended adjusting the screw no more than "five minutes" at the time, meaning you imagine the screw head being a clock face and turn it only the equivilent of five minutes rotation at a time, then check the tension before adjusting it more.
I can't tell you how common it was with machines coming in where someone had tried to adjust things like that without realizing how delicate some of the parts are.

Also, you need a good way to tell if you have it right or not.
There is a trick where you thread the bobbin in the casing and hold it up by the end on the thread and judge by how fast the casing drops, but that only works if you already know what is right for your machine.
You can of course thread the machine and try sewing a seam, but that only works if you are absolutesly sure that the upper thread tension is spot on and unobstructed (if there is lint or gunk in the tension mechanism, that will have an effect on the tension.)
If you get thread loops on top, the bobbin tension is too low.
If you get loops underneath, the upper thread is too loose.
If the entire seam is so tight it wrinkles the fabric, but no loops can be seen either side, both threads have too high tension.
If everything just tangles up in an uncontrolled mess, both threads could be way too loose, but it could be a number of other things as well. (Including, but not limited to: bad thread, poorly wound bobbin, lint build up under the stich plate or in the bobbin case, misaligned parts after a botched cleaning job in the area where you insert the bobbin case, damage on the needle, stich plate, presser foot, bobbin case and so on.)

Bernina is one of those brands that are a little bit all over the place. I have seen some great machines and we had several regular customers that swore by them and used them in their work. But it was also fairly common that Bernina machines came in with tension problems. We did have a case where the machine ran beautifully in the store and the car ride home was enough to require things to be readjusted again. This was the kind of adjustments that could be easily done at home, so no damage done, but still, I don't think I ever seen a machine that sensitive before or after.

If I was you I would have it serviced by a reputable professional before starting to make adjustments of my own, just in case there is a build up of dust, solidified grease or anything else in the machine that could cause things to break if you start to turn knobs and run the machine. I say this mostly in the light of how long this machine has been unused.

But if you do want to try to fix things yourself, this is my advice based on what I've seen in too many machines where such home fixes have gone wrong or at least failed to solve the problems.
1. Adjust one thing at the time, only. Never be tempted to randomly start fiddle with this and that in the hopes that is will magically solve anything. If you think you are on the wrong track or have gone as far as you can with one thing, reset it to the original position before moving on to something else. If you don't you will never know exactly what made the difference even if you find yourself getting resaults. And take notes. lot's of them.
2. Never adjust something that you don't have a way to evaluate the effects of.
3. If you fail and then turn the machine over to someone else, make sure to tell them what you have done when trying to fix things. This is especcially important if you have opened the machine up. This is in part to make their job a little bit easier, but there is a second reason. This is going to sound a bit fabulous, but did you know some machines are actually sort of bobie trapped so that if you open them up without knowing what you do, the machine can be rendered useless? This in not common and I honestly don't know if Bernina specifically ever did it, but it's a thing.
Even if something has gone horribly wrong, even if you feel embarresed or stupid, or don't want to throw you nice dad who thought he could fix the machine for free under the buss, or whatever it is; just be honest about it. The repairman is going to know either way and he has probably seen worse. Trust me on that one... Oh the stories I could tell.

 

Before sewing machines could reverse, people left a long tail of thread at the end of a seam and sewed it in by hand if it needed it (which it only really does if the end of the seamisn't crossed by another seam later in the construction process).

As a really old fart who remembers machines that didn't reverse, I learned these things as part of the sewing process.....

Teddy

 

Another trick is to pull the upper thread to the back and simply tie the two threads together. It's not as secute as the method Teddy sugested, but it's very quick and discrete.
A third way is to stop with the needle down, lift the presser foot and simply pivot the entire piece 180 degree and "reverse" that way. It works best for simple seams on small pieces, of course, but doll clothes tend to have a lot of those.

 

Sounds like tension issue to me, the looping at bottom. Can take the bobbin casing and with your fingernail tighten the tiny screw on that a little bit, for easy fix.

 

Have you oiled the machine lately? Also check that there isn't a loose thread in between the tension discs or in the bobbin area, but it's best to send her in for a service if you can.

 

I also strongly suggest locating the manual for the machine and reading it thoroughly. You might be able to find it online. Do not mess with the bobbin thread tension - it is the very last resort.
The manual should tell you how to start stitching - with some machines you do need to pull the ends of threads when starting, and with others you do not or it will mess up stitches. Try stitching on scraps and begin the stitching line away from the edge of the fabric.
If you ever figure out where the service place is, they will adjust it for you properly.

 

Really late to the game, but I have a Bernina Artista 150 and they are FINICKY about their bobbins. I have on more than one occasion completely unreeled an re-spooled my bobbins to get them to work. Also make sure you have the correct bobbins, they do not take standard class bobbins, but the visual differences are minimal. I have to carefully segregate my Bernina bobbins from all my other machines. (My current count is six machines, I think)