Help needed with sewing 100% polyester + small peak in my man cave

[Dabberty]

So much info thanks very much.
I am actually now looking forward of trying it again when i get home tonight.
(this morning I was very disappointed after making he video)
Will keep you updated !

[Pag]

Well after seeing the new vid it apppears that your Presser foot pressure and needle plate aren't your culprit. The bobbin case looks very similar to a machine that I had and it looks threaded properly. There is another possible cause that I can think of though. What size needle are you using? The tighter weave on polyester coupled with the higher dimensional stability may require a different needle size. Too small needles may make too small of a curtain (loop on the back of the needle the hook grabs). Too large of a needle may make the needle push some fibers down too far causing the curtain to be too small also. For poly on one of my machines I have to use a size 14 needle, any other size and i get results like yours. My machine will behave differently than your machine so your needle size may be different.

This is highly speculative and I'm assuming that your machine sews well on other fabric types. If it does make nice stitches on other fabrics I would say your timing is not an issue but spacing may be. For the most part hooks last a VERY long time and don't wear out for most people. Hooks are however a wearable item just like loopers. Some fabric/thread combinations are more forgiving than others when it comes to hook/needle spacing.

I'm rooting for a good outcome here

[Ramblinrev]

Well after seeing the new vid it apppears that your Presser foot pressure and needle plate aren't your culprit. The bobbin case looks very similar to a machine that I had and it looks threaded properly.

I agree the presser foot and throat plate are not the culprits. I think it would be worth the effort to try altering the threading of the bobbin case to leave the thread loose after it exits the leaf spring tension plate. Any vertical bobbin case I have seen is made that way including the one I am using now. I think that extra hole after the tension spring is restricting the bobbin thread once it is picked up initially. Having eliminated the other obvious culprits, there seems to be an issue with the bobbin/hook mechanism. Before I chased my tail around trying different needle sizes (that _is_ a possible issue but not my most likely) I would simply rethread the bobbin case and give it a whirl.

[Pag]

Doesn't hurt to try leaving it loose but I own a machine that also must b threaded through a retainer after the spring plate. If it breaks the bobbin thread without the retainer on the bobbin, the next cheap thing to try would be needles IMO.

[Ramblinrev]

Doesn't hurt to try leaving it loose but I own a machine that also must b threaded through a retainer after the spring plate. If it breaks the bobbin thread without the retainer on the bobbin, the next cheap thing to try would be needles IMO.

I agree....
That's the process I would use.

I have said time and time again there is no "universal" threading system for bobbins... even between models by the same manufacturer. At this point... what Sherlock Holmes says holds true... "When you have eliminated the impossible, whatever remains, how ever improbable, must be the truth.

[Dabberty]

Some luck ! but without luck...

Yesterday, I searched a lot on the local "ebay" site of Czech Republic, and found a few machines like this one.
They are all from the Communist era, mine was build around 37 years ago..
I contacted a lady who had the same machine for sale, but she said it was already sold. But I told her I wasn't interested in the machine itself, but more if she knows how to thread one properly.
She said she didn't cause the machine belonged to her mother, and that lady died. But she said that she still has the original manual, because the person who bought the machine didn't want it. So i hopped in my car, and picked up the manual :-)

The bobbin threading was same like the other old lady told me, the machine threading was a bit different, so I tried that like described in the manual.

Sadly, no success..
It even seems it does not sew anything anymore now...

Here some answers to your questions, and also a new but very short video with some original pics of the threading


With the foot lowered to the feed dogs, is there tension on the needle thread when pulling it through the needle? And does it pull on the "U" shaped spring on the tension device? Does the tension decrease when the foot is raised?
yes, yes, and no..

I watched the new video, and the only thing I wondered about was your description of the path of the bobbin thread ("through a hole"?) as it came out of the bobbin case after passing under the tension spring. Did you mean the small notch near the end of the spring? I'd guess probably so, in which case it looks fine.
Nope, meant the additional hole after the spring, see new vid for explanation and a pic of the manuals threading pic

What size needle are you using?
Size "70".. see new vid for more info..

I suspect the hook is to far from the needle (if it is threaded correctly). look at your needle, there should be a scarf (cutout) above the eye, with the bobbin removed and the machine out of the table look as you rotate the wheel by hand, the bobbin hook should pass the needle as the needle goes up, just above the eye, and be as close to the needle as possible without touching, about 1 paper thickness. If the timing is off it may be more than you want to deal with.
The timing seems right if I understood you correctly, but the paper thickness is far off. I would say more then 10 papers thick space between the needle and the hook..
I hope it is visible enough in the video..

Didn't have white thread available, but in the first video i put here, you can somehow see the result of sewing the polyester.. If it is not clear enough, let me know and i will make some pics.

http://www.youtube.com/watch?v=bWlEl7yDqVc

[Ramblinrev]

Well... it seems we are ruling some things out little by little. That at least is progress. The relationship between the hook and the needle is critical to the machine working properly. Everything seems to be threaded properly.

It would seem there may be a problem with the spool tensioning system. In my experience, the tension should release when the presser foot is raised. In your above response you seem to suggest it does not. That could indicate a problem with the internal linkage of the machine. It could be that linkage that is also affecting the hook position.

Play around with some needle sizes like Pag suggests. But I kind of suspect the problem is beyond what on line help can resolve. My next suggestion would be to find a good repair shop and have the machine serviced. Unless you can find a technical service manual for the machine. Somewhere I think you are dealing with some linkage problems.

[TZBrown]

From the loose and loopy upper thread in the last video I am still not sure the upper is threaded correctly.

As you thread around the tension knob, making sure you are between the tension discs, pull up pretty hard on the thread before you go up to the lift arm.
The thread should snap into a spring and then as you lower the thread the spring will pull it back down.

I did a short video on an older machine, not like yours but they all operate basically the same with a rotary hook.

You have al ready covered some of the items I show as I did not see your latest video before I did that one.

Some adjustments will be different for yours, as your bobbin is in front of the shaft.

If the upper turns out to be threaded properly then the hook to needle distance is off for sure.

Did it ever sew since you have had it? If it did did, has it been jambed with material or thread which might have moved some parts?

Will it sew on about 3 layers of sweat shirt material?

[Dabberty]

Mr TZBrown, thank you very much for the video, now I have a better understanding of the needle / hook combination.
Compared to yours, I think mine is pretty off.
But before I will take it apart, please have a look at this close up of my needle / hook / tensioner video, and confirm if it is too far from each other, and the timing.
If yes, I will start taking it apart tonight.

http://www.youtube.com/watch?v=F2mxUeoGbKs

[TZBrown]

Before you try to adjust the hook, try tightening the tension up real far
since it did sew on heavy fabric, it may just be a bit odd.
If it sews, back off tension until the twist is inside the fabric and not on top.

I do not see any tension release when using the foot lift, not unusual, just different.

And check in video 3 at 1:04 you have a pic of the thread diagram, it is not really clear, but I am sure it is written better.
1. does the thread go from the tension discs and spring, straight to the lift arm, or
2. does it go from the tension discs and spring through the guide to the left of the thread tension and then up to the lift arm, then back through the same guide and on to the needle?
If it goes as the second description we are missing something still in the threading near the tension spring.

Is there a set screw to the right of the thread tension device in the body of the machine? Does it hold the complete tension device into the machine?
If there is one it may be possible that the complete tension device has rotated clockwise and moved the spring out of position.
Some machines have this feature, and since your tension center screw is slotted yours may,
If you have that feature, loosen the setscrew and rotate the complete assembly counter clockwise until the pin from the rear plate is at 12:00 and then tighten up the screw, re thread and try again.

Usually the tension spring will move about 8mm during the stroke of the needle.

In vid 4 the hook is quite a ways from the needle. at 1:04 of the vid you can see a set screw in the left side of the screen. scribe the shaft and the rotating part first,
loosen the screw and move the part closer to the needle BUT DO NOT ALLOW IT TO ROTATE ON THE SHAFT, that will affect other timing.
Basically the tip of the hook should pass about .5 to .8mm above the center of the eye of the needle on the up stroke.