Juki LU-563 keeps thread jamming

[hemiyota]

I picked up this machine about a month ago. Got it cleaned and oiled. Threaded it and started practicing on vinyl. Got tired of practicing and decided to actually sew something.  Made a cover for the machine. Couple days later, tried to sew again and no way. Thread keeps jamming. It will actually pull the top thread, that I'm holding, into the machine  and jam. Popped the safety clutch once. Set the hook timing. Same thing. I've had it apart, those 3 little screws, about 8 times. It just keeps pulling thread in and jamming.. Nothing was changed since I made the cover, it just quit....Any ideas?

[friquant]

Try this: Start and end each seam with the take-up lever at its highest point. (Otherwise the machine will yank the thread out of your hands when the seam begins)

Also post a photo of how you've got the top thread threaded, from spool to needle eye. Just in case it's misthreaded.

And check the timing. I like to check where the hook shoulder is when the take up lever is at its lowest point. If the timing is retarded too much, the take up lever will yank hard on the thread before the thread reaches the apex of its path around the bobbin. And if the timing is advanced too much, the hook will grab the loop of thread every turn (instead of every other turn) and lock the machine up.

If still not working, can post a close-up video of the needle and bobbin area with the bobbin cover off. Turn the handwheel very slowly for the video, on the order of ten seconds per revolution, so we can see the interaction of the different pieces. Hope this helps!

[kgg]

5 hours ago, hemiyota said:

Thread keeps jamming.

A couple of questions:

i) What are you trying to sew?? Leather or fabric and how thick??

ii) What size of thread are you using as a top thread??

iii) What size of thread in the bobbin??

A few photo's of the top threading from the thread spool to the eye of the needle would really be helpful in narrowing the problem down.

Assuming your hook to needle timing is correct check

i) incorrect threading

ii) damaged bobbin case

iii) faulty bobbin or installed backwards

iv) improper tension settings bobbin and top thread

v) needle bent

vi) wrong system needle. 135 X 17 X needle size is for fabric and 135 X 16 X needle size is for leather,

vii) wrong size of needle vs thread size

viii) dull or bent bent needle

ix) debris buildup in or under the bobbin area.

x) threads (bobbin and top thread) not being held for the first few stitches before being back stitched and locked.

kgg

 

 

 

[hemiyota]

It was sewing perfectly fine just a couple days earlier. Nothing was changed. Still threaded the same. Sewing vinyl. T90 top thread, not sure of bobbin, but it isn't too small or large, and worked fine for all the other sewing I was doing. Set the timing and needle height. I'll take a video.

[friquant]

1 hour ago, hemiyota said:

I'll take a video.

📹  

[hemiyota]

Here's a video from last night. Surprisingly it didn't jam, but probably would have if I had sewn some more. The rats nest on the vinyl pieces were from when I was playing with the thread tension. I thought that it might be too tight and that was why it was pulling the top thread  from the table. Not the problem. I'll post another video, like someone suggested, of hand sewing and having the bobbin rotate very slowly......

 

Edited 4 hours ago by hemiyota
using smaller video

[friquant]

@AlZilla here is a smaller version of the above video if you are able to replace it

 

[hemiyota]

I replaced it, thanks!!

[kgg]

3 hours ago, hemiyota said:

Here's a video from last night.

I watched your video and here is my two cents worth.

i) When you started you did not hold the thread properly to prevent thread movement (Top and Bobbin) like you did at the 5:54 mark.

ii) At the 3.10 mark you can see the top thread (black thread) gets pulled in slightly which is causing a slack in the top thread and causing a jam at the 3:20 mark.

iii) You did not back stitch after three stitches to lock the thread before starting your seam. 

iv) When you finish the seam you are not back stitching to lock the thread.

v) With a thin piece of material like what you are using in the video there is almost not space to bury the bobbin thread knot in the material particularly with thicker thread and vinyl is a sticky material as far as the thread is concerned and will want to catch on the sides of the hole the needle makes. Keep in mind for every hole of each stitch you have the thickness of three threads (top thread and the two halves of the bobbin loop).

vi) When finishing the seam and after back stitching try hand wheeling the needle up to the point where the tension disc release before removing the material.

What size of needle are you using???? What size of thread???

kgg

 

[friquant]

Love the sound!

Looks like you're having trouble getting the machine to let go of your thread when you have finished a seam. Here is what I recommend:

1. Before you start your seam, turn the handwheel so that the takeup lever is at its highest point. Otherwise, the takeup lever may try to snatch the thread out of your fingers. (You can do the opposite---takeup lever at lowest point---if you want to experience the snatch firsthand!)
2. At the end of your seam, before you pull the material out from under the presser, turn the handwheel so the takeup lever is again at its highest point. This does two things. First, it locks your final stitch. Second, the top thread will not be wrapped around the bobbin when you go to take the material out. 
3. Since you ended your seam with the takeup lever at its highest point, it's already in position to start the next seam 😊