Machine problems - and problems solved - but not by the Lego repair team

I've had a couple of recent issues with my sewing machine,  a Bernina 350, which I take to classes. I really like this machine, so was quite upset when it wasn't behaving properly.

Library image - not my machine

A couple of times it snarled up, jammed. A couple of times,  threads shredded. I put that down to poor threads - one was machine embroidery thread and mine was apparently not at all good quality - I hadn't known that. That or needles of too small a size. A combination of these two. Thread nests on the underside were usually sorted by carefully rethreading. I had to be careful of the fabric being pulled under. On one occasion, a brand new needle was faulty (a raggy burr) and it took me a bit to realise that. I know now to check even new needles. Usually, a reason became apparent. Occasionally,  the foot pedal seemed not to work.

I keep my machine cleaned and lubricated. I try to use the correct needles and thread - though as you will see, I don’t always succeed.

Recently in class we have been making a child's padded gilet. The outer fabric (ripstop nylon) wasn't the easiest to work with but no major problems. The jacket is lined in nasty, very nasty, fur fabric. Disgusting stuff which stretches and sheds. Two weeks ago,  I had to stay stitch this lining. This was at the end of the class. My machine threw up its hands in horror and refused to sew. I gave up for the night. Afterwards,  the machine seemed fine when I used it at home during the break for other projects.

View of the fur, right side

Fur and zip facings - I haven't got this far yet

Not mine - I haven't got as far as this yet. Overall view of jacket inside

This week,  back at class after the mid term break, I still had to do the stay stitching (I hadn't done my homework, hangs head in shame). My machine hated this. It kept jamming with threads caught underneath. Worse,  fur scraps were getting caught in the eye of the needle, on the thread, everywhere - very difficult to sort out. I gave up and stay stitched on the industrial machine in class (not without issue!).  No one found the fabric easy to work with,  and I include the tutor here, though others did manage. The tutor says she would use polar fleece another time. I can assure you I won't be using this fabric again! Polar fleece - maybe.

After the stay stitching and attaching sides and shoulders,  the next step was to attach the facings. I tried to join the back lower facing to the side lower facings, so no fur involved at this stage - no thank you,  said my machine. Now,  I had very loose stitching underneath; I had noticed that the machine sounded 'rougher' than usual but the stitching on the top had seemed okay for the couple of inches that I stitched. That pointed to an upper threading problem, I thought. I checked and rethreaded repeatedly, both upper and lower threads.  I changed the needle as I wondered if there was a slight burr  (afterwards btw it became clear that there was). I made sure there was no fur caught. The machine appeared clean.

I asked the tutor for help. She went through the same processes.  She thought the shuttle had a bent part and demonstrated this with a card comparing it to the shuttle from another older Bernina. She advised me not to use the machine and I agreed to take it to my dealer. In the meantime,  I worked on the older Bernina without issue. With all the shenanigans, I am way behind,  of course - we were supposed to finish the gilet in class so I have that to do.

At home,  I emailed the dealer to say I'd be coming and described the problems and my tutor’s thoughts. I rechecked  my machine and got David to look at it too. Clean as a whistle. David didn't think there was any evidence that the shuttle was distorted (nor did I).  It fit in the race perfectly. I thought it might be the thread I was using as this was a cheaper thread in order to get the colour I needed for the gilet. I changed the thread to a good quality thread in both bobbin and top. I then did a test straight stitch. No problem. So had it been the thread? I tried a zigzag stitch and things went pear shaped. The stitch became very narrow and no longer a proper zigzag stitch. It became clear that the thread was caught up in the upper innards of my machine. I couldn't do anything about this. Off to the dealer this afternoon.

Thread stuck tight

I got to the dealer who was very intrigued following my email. He asked me what the tutor had meant and I demonstrated. Long story short, there was no problem with this - newer machines have a different shaped part. I understand that this is a cutout to allow zigzag stitching. The bend is there for a reason.

He untangled the thread - there was no obvious reason for this. He had to open up the machine and there was no fur lurking there! He found that the bobbin tension was much too loose and corrected that. He told me that vibration is the culprit here. I had never even once checked that my bobbin tension was correct as I understood that this wasn’t for the likes of me to tamper with! I’ll keep an eye on it in future. I’d never had to alter tension there as my sewing is all pretty standard dressmaking. Until recently, I hadn't noticed any issue with stitch quality.

I said about the foot pedal occasionally not working. He quickly found that there was a break in the cable and fixed that.

He also replaced my broken manual cutter.

He lubricated (although I have lubricated regularly, I then wondered if perhaps I hadn't done this often enough - but I didn't ask the question. No need to clean or remove debris.

In test stitching , he changed my needle to a bigger one. You actually can’t use the threader with a 70 - I had been using a microtex 70 for this test and this is clearly rather on the small side.

My 3 year service is due in June - the machine has a 7 year warranty but the 3 year service is mandatory to keep that valid.  This was a quick repair and I’m more than happy. For the service, they do a lot more and need to keep the machine for a few days.

Conclusion:

1. I believe my needle was too small for the thread I was using, and possibly for the fabric
2. My thread wasn't the best quality, though reasonable. I usually use Guterman, but it was black Guterman that jammed in my test at home
3. The bobbin tension was much too loose - I guess this was the primary problem
4. There was, indeed, a break in the cable to the foot pedal causing the issues I’d found
5. There was no problem with the shuttle/race
6. My machine is perfectly fine

Maybe if I’d had David’s assistants helping me I wouldn’t have run into these problems!

Lego Repair Team
Photo by David - his machine, Dolly

Unfortunately, as this repair involved a whole team of workers, it could be very difficult to get them together again in the same place at the same time.