MarineBob

I guess this wonderful machine falls into vintage category. I got it as a hand-me-down years ago and I have used it occasionally. Never had many problems but now working on a cushion cover project I have had lots of problems with top thread bunching up under the fabric. After lots of looking at YouTube etc I have pretty much concluded and proved the issue was the top tensioning.
Here is my question. When I was getting going, I checked to see how to thread through the tensioner on top. The disc on my machine was more or less in the middle of the slot so I did not know on which side the thread went. Tried either side, lots of tension adjustment.....lots of great sewing interrupted by frequent big bunchups. As I mentioned, after lots of frustration I concluded the tensioner was not right. The thread seemed to keep popping out towards the top of the slot and getting loose.

So, I took the tensioner out of the top cover and found some (not lots) fuzz etc in there. After cleaning it up with alcohol, the disc now seems to go to the right side when not engaged, not really allowing the thread to to go on either side. It has to go on the left side and now the machine seems to work fine,,,,,no issues. I also but a tiny drop of oil on the push rod that disengages the tension disc. That pin was sticky

I think I solved the problem and I have no regrets since this is a a nice machine and given its age, a clean up was in order. Am I on the right track? Did my fix really attack the tensioning problem? Seems to me it did but I am wondering if there is anything else to look at. Thanks for others experience

lwbuchholz

I have one of those and haven't had a problem with the tension. Do you have a manual? It might give you some ideas. It sounds like you did the right thing though. I love this machine and wish I had another.

quiltedsunshine

Sounds like you did good! I would not, however, put oil anywhere inside the tension assembly. If it's gummy, I clean it up with a little WD-40. (Sorry, I know some people get up tight when I say that.) When you put the tension assembly back into the machine, it should push against the left side of the machine to be installed correctly. It's kind of spring-loaded.

You can use either side of the tension disks. There are two slots so you can use two threads with a double needle.

If you're using a heavier thread (for upholstery) you'll need to tighten the upper tension about as tight as it will go to get a good stitch. And if you're feeding it from a large cone behind the machine, the thread needs to wrap behind a spool pin to keep it from popping out of the tension.

That is my favorite mechanical machine of all time! I've worked on hundreds of them.

MarineBob

Thanks for the responses

I have the original user book. Its pretty good but as far as top tension, it just says put the thread in the slot. No mention of which side of the disc. Makes sense either side ought to work. When I took the assembly out of the cover, it became clear how it works. Pretty simple really. It makes sense that two strands would have more or less equal pressure on them. Aside from a bit of crud and a couple of fuzz balls it was in good shape. The spot I put a tiny drop of lube was on the pin that gets pushed in by the presser foot arm. It releases the tension and it was sticky a bit. Now it is smooth. I don't think it made difference but at least it does not stick at all

The thread I am using is a bonded nylon. Its pretty strong and slick. It does not seem a lot thicker than regular sewing thread so I am not sure how much tension it needs but I will for sure do some testing at various settings.

The thread is feeding off a big vertical spool and I wrap it around the spool pins to at least get it moving towards the clip on the back side of the machine. I am thinking I need to make some sort of light tension device to keep a tad of pressure on the thread as it feeds off the spool. We'll see how today's session goes with some experimenting. Good news I have figured out the source of my problems, not just some fine tuning

quiltedsunshine

Good idea! For a little added tension, you can actually wrap it around the bobbin winder tensioner, before it goes into the back clip.

MarineBob

Obvious solution......sometimes its just staring you in the face.....Thanks for that idea

aashley333

I've been sewing on this machine for 40 years. All I've done is have it cleaned and oiled a few times. I have been watching videos about tension because my newly acquired Bernina Industrial 950 is looping on the bottom of fabric even though the tension is as tight as it can be. One video suggested cleaning tension disc with a pipe cleaner. Another said to always have presser foot raised when threading, which I never paid attention to. I'm gonna try the wrap around bobbin winder tip!

MarineBob

On my old Bernina when the shoe is down the top tension is engaged, when its up, top tension is relieved. There is a mechanical linkage/arm that takes care of that action. I have been pressing on with my cushion project with just about zero tension issues. Took me a couple of steps to get straightened out. One.....I had to recognize the problem was top tension was not working right. Second, I think what was going on was within the top tension discs there was a bit of 40 year old built up crud and the small pin that pushed to release and engage the top tensioner was goo'd up a bit. I cleaned the disc assembly out with some alcohol and a folded edge of a an old hanky. As far as the release on, I think sometimes it was releasing thereby engaging the tension and sometimes it was sticking which kept the tension from coming on when the shoe was put down. I put a tiny bit of thin oil on it and worked that pin in and out a dozen times and its now smooth and free, where before it seemed sticky. My problems were intermittent which drove me nuts. But the good news is I think I got it solved. If you have the bottom loops I think that is top tension. But just because the setting is high, it does not mean necessarily the discs are working correctly. I have no idea about your machine but take a look when you engage the shoe to make sure there is tension on the top. That is where my intermittent problems were finally identified.

quiltedsunshine

When you lift the presser foot, the tension disks are open, when the presser foot is down, the tension disks are closed. So, yes, thread with the presser foot up.

Also, check to see that the "tension release" is working. After threading the top, pull the thread with the presser foot up and it should pull through easily. Put the presser foot down, and the thread should be tight. If it isn't tight when the foot is down, the "tension release" mechanism may need to be "adjusted," aka: bent.

MarineBob

Since the top tension is normally set on (with the foot down) the lever provides for movement of a small pin in the disc assembly when the hold down is lifted. I think that was part of my problem in that the pin would not come out and engage the tension discs all the time each time I lowered the foot. Intermittent problems are the worst. I tiny bit of thin lube and working the pin in and out a few times seemed to help