The Upholstery Forum

Good day, everyone!

My machine seems to be threaded correctly, but for some reason the thread is fraying and eventually snaps. Any help would be greatly appreciated. I've attached photos for reference.

I'm on a used Juki DNU-1541.

Thanks in advance,
J Wilson

The thread has to travel back and forth through the eye of the needle quite a bit as the loop around the bobbin is made and the slack taken up as the stitch is tightened. If the needle is too small for the thread, the thread will fray.

Did it ever sew correctly and, if so, what did the stitches look like? They should not show evidence of high tension on the top stitches, which would be evidenced by the appearance of the bobbin thread in the top stitches.
Is this a new thing, or did you just get the machine and are having this problem from the get-go?
I think your machine is threaded correctly, but are there any burrs along the thread path, including between the discs? Is the area between the discs clean?
Is there anything that would increase the tension in the thread, going all the way back to the thread cone? You should be able to set the top thread tension with the tension mechanism with the thread looped twice through the thread guides as you have done.

A properly sized needle should dance down a piece of thread that is held taut at a 45* angle. If it doesn't slide, it is too small. If it slides easily, it is too large. If it is just right then it will sort of wiggle and dance its way down the thread.

The first thing I would try would be a larger needle. I find that different threads of the same size may require slightly different needle sizes.

Here are some shots of my set-up and the needle that I am using with the V-69 that is in the machine.

There is something causing an an abrasion in the path of the thread. The most common cause of this is cheep thread. What brand thread are you using?
other causes can be:
- needle bad or too small
- a bur or sharp edge anywhere in the needle
- a miss alignment of the hook and needle timing causing the hook to slightly cut the thread.

I hope this helps

Thank you both!!! I appreciate your help. I think it is the needle size. I had a thinner thread on it previously before I switched it out for this one. I'll change up the needle and let you know.

Thank you both again!!!

Cheers,
J

Needle size, I had the same issue, ad it wasn't the $120.00 Tenara thread, step up a size or two. I have the Consew 1541S, same as your's.

Thank you. I'm glad it was easy to address.

@John

The thread I'm using is V-92 Polyster Thread from Sailrite. I switched out the needle from a size 22 to a size 25 and it still frayed. Any assistance would be great appreciated.

Take it out of the bottom guide where the needle attaches and see if it is not binding or abrading there. That looks like a good place to have a sharp edge. I have an Adler machine so I have not seen thread pass quite that way before but it looks "iffy" to me there.

John

I'll give it a go. Thank you for your help!

Hook tip is most likely splitting your thread. Check needle bar height, hook timing and clearance from the needle, check/reset saftey clutch. Here is the service manual for your machine and some general trouble shooting notes i found in some old archives.

All great suggestions, but just one more idea: I had the same issue. It turns out I just needed to replace the needle. Not with a bigger size, just a new one as the old one started to form microscopic burrs. Mine was an easy fix even though I felt dumb.

I also have a Juki 1541, my bets are
1) the timing is off
2) hook too far from needle
3) your thread is wound too tight on the spool and requires too much effort to unspool.

@J Wilson , double check that you have your needle installed correctly. Go back to the apprentice course and watch installing the needle. If it is in wrong that thread wont slide up the groove and fray.