Backlash issue with Juki 1541 & bonded thread

[aslfkjaslfkjasflkj]

I am using V69 Bonded Polyester thread in my Juki 1541 and I'm having backlash issues.

I'm using steel bobbing and I have tried tightening the bobbin tension to no avail. I have tried using a backlash spring (pictured) however this causes inconsistencies in the stitch and I still sometimes get backlash. I have tested with the spring in a tension guage and the tension goes up and down. Without the spring it is consistent. I have also tried multiple springs.

I sew at 100spm and at this point I'm at my wits end. 

Is there anything I'm missing?

Kind Regards 

Edited December 11, 2021 by aslfkjaslfkjasflkj

[Wizcrafts]

Always insert the bobbin so it feeds against the direction of the hook. If the hook turns clockwise, insert the bobbin counterclockwise. This may cause the bobbin thread to me a sharp turn into the slot that feed under the tension spring. I find this to be more controllable unless the thread is particularly sticky.

[aslfkjaslfkjasflkj]

20 minutes ago, Wizcrafts said:

Always insert the bobbin so it feeds against the direction of the hook. If the hook turns clockwise, insert the bobbin counterclockwise. This may cause the bobbin thread to me a sharp turn into the slot that feed under the tension spring. I find this to be more controllable unless the thread is particularly sticky.

I think I have tried this in the past however I will try again.

Just to be clear, when you refer to the rotation of the hook. If I load the bobbin from the side and look at the hook from this angle, in my case the left side of the machine. The hook spins counter clockwise. So I should insert the bobbin so that it spins counter clockwise as when inserted this will spin opposite the machine. Hopefully I got that right.

Also should I bother with the backlash spring? As the inconsistency in tension leaves a poor stitch which in my opinion is worse than the backlash as most of my sewing consists of straight lines and not having to stop.

Thanks

[Wizcrafts]

33 minutes ago, aslfkjaslfkjasflkj said:

Also should I bother with the backlash spring? As the inconsistency in tension leaves a poor stitch which in my opinion is worse than the backlash as most of my sewing consists of straight lines and not having to stop.

If the spring interferes, leave it out. Load the bobbin so it feeds against the rotation of the hook and make sure you feed the thread under the tension spring and that there are no thread stubs stuck in the slot or spring. Then adjust the bobbin tension for a smooth, steady pull. If you use the proper needle size for the thread combination, the top tension should bring the knots into the center of the work, consistently. Watch the thread spool as it unwinds to see if it is forming kinks. Some machines have a top post with multiple holes that allow you to loop the top thread around upper and lower guide holes in the opposite direction of the twist of the thread. This can counteract excessively twisty thread.

[aslfkjaslfkjasflkj]

59 minutes ago, Wizcrafts said:

If the spring interferes, leave it out. Load the bobbin so it feeds against the rotation of the hook and make sure you feed the thread under the tension spring and that there are no thread stubs stuck in the slot or spring. Then adjust the bobbin tension for a smooth, steady pull. If you use the proper needle size for the thread combination, the top tension should bring the knots into the center of the work, consistently. Watch the thread spool as it unwinds to see if it is forming kinks. Some machines have a top post with multiple holes that allow you to loop the top thread around upper and lower guide holes in the opposite direction of the twist of the thread. This can counteract excessively twisty thread.

Thank you for the help thus far.

I am using a thread guide pin/top post and threading it counterclockwise opposite of the direction coming off the spool.

The needle size is something I'm a bit unsure of. I was originally using size 18 serv7 needles. Which seemed fine for a few layers of 1000d and lining however I'm now sewing bag pieces together where I have a minimum of 7 layers and up to 14 in some parts of the same stitch. I then sized up to a size 19 needle.

Would this be too large? My thought was that the thread seemed to be having a hard time going through thicker seams so I sized up.

[kgg]

3 hours ago, aslfkjaslfkjasflkj said:

I'm using steel bobbing

I assume you mean bobbin. My Juki 1541S can be cranky with bobbins if I mistakenly use an after market bobbin while the Juki bobbins never give me a problem. That said if you are having problems with a backlash spring don't use it. Also I find if I use a bobbin that has been wound with thread for more then a couple of days before use it I may have problems as the thread will develop a coil spring memory and cause problems. I also found that using 8 oz spools of thread created problems both with the top thread and bobbin thread with black thread being worst. I would do as Wiz suggested and also change the spool of thread to a brand name preferably in a 16 oz spool size.

Can I ask why you are using V69 thread and what you are trying to sew. If the material is to thin it may not be a backlash problem my Juki hates thin stuff. You may have better luck using V92 as a top thread and bobbin thread. A couple of photo's of your thread path would also help.

kgg

[aslfkjaslfkjasflkj]

49 minutes ago, kgg said:

I assume you mean bobbin. My Juki 1541S can be cranky with bobbins if I mistakenly use an after market bobbin while the Juki bobbins never give me a problem. That said if you are having problems with a backlash spring don't use it. Also I find if I use a bobbin that has been wound with thread for more then a couple of days before use it I may have problems as the thread will develop a coil spring memory and cause problems. I also found that using 8 oz spools of thread created problems both with the top thread and bobbin thread with black thread being worst. I would do as Wiz suggested and also change the spool of thread to a brand name preferably in a 16 oz spool size.

Can I ask why you are using V69 thread and what you are trying to sew. If the material is to thin it may not be a backlash problem my Juki hates thin stuff. You may have better luck using V92 as a top thread and bobbin thread. A couple of photo's of your thread path would also help.

kgg

Yes I meant bobbin. I am using aftermarket bobbins so I might look into some genuine ones if I can't get this resolved. I've also read that aluminum bobbins are supposed to be better for backlash. Any input of this?

I will update this thread on monday with my thread path. I am using A&E Sunstop 3000m v69 grey thread.

I am sewing a sling bag. I'm using 1000d PU Nylon and ripstop lining. I am now sewing all the pieces together, which as mentioned previously I have a minimum seam of 7 layers up to 14 in some parts.

I've had issues with consistent stitches but I put this down to a number of things. This machine is second hand and didn't come with all the thread guides etc. I recently purchased all the missing parts. But I still have issues with the backlash. I've always placed the bobbin into the case as shown in the manual. I will try it the other way as wiz suggested.

 

[Wizcrafts]

1 hour ago, aslfkjaslfkjasflkj said:

I am sewing a sling bag. I'm using 1000d PU Nylon and ripstop lining. I am now sewing all the pieces together, which as mentioned previously I have a minimum seam of 7 layers up to 14 in some parts.

I would seriously think about moving up to #92 (T90) thread for this thickness and a #20 needle. Normally, I use a #19 needle with #92 thread. But, sometimes the little extra diameter of a #20 needle makes it easier to balance the knots. You are sewing tough material. Number 69 thread has under 11 pounds test. Number 92 is rated at 15 pounds and is less likely to rip apart under stress from so many layers In fact, you might even be able to get away with #138 thread, rated at 22 pounds test, using a #22 needle. Experiment!

I sew a lot of patches onto leather vests. I find #69 thread to be barely acceptable for low stress patches, or for soft leather, or denim. But, if I am sewing through a thick vest and the patches are substantial, I move up to #92 thread and a #19 needle.

[kgg]

1 hour ago, aslfkjaslfkjasflkj said:

I've also read that aluminum bobbins are supposed to be better for backlash. Any input of this?

I have some of those as they came with my Kobe LS 1341 and I will not use them. The tolerances and balance can be all over the place so I don't think they would be of any benefit.

1 hour ago, aslfkjaslfkjasflkj said:

I am sewing a sling bag. I'm using 1000d PU Nylon and ripstop lining. I am now sewing all the pieces together, which as mentioned previously I have a minimum seam of 7 layers up to 14 in some parts.

I don't think you are having as much a backlash problem rather a problem with the material. I find that to sew thin stuff particularly with ripstop it can become a real balancing act in getting the bobbin thread to properly set. I put the problem down being caused by the makeup of the ripstop. I find some things that are less then 4 to 5mm in thickness a bit of a chore with the 1541S so for those items I use the less capable 1181n. A good reference to show how the 1541 reacts with light, medium and heavy fabric take a look at youtube.com/watch?v=4JES-2I7h3o versus the less capable 1181N with the same material youtube.com/watch?v=IKJuKTrjsbw&t=300s

kgg

[aslfkjaslfkjasflkj]

1 hour ago, kgg said:

I have some of those as they came with my Kobe LS 1341 and I will not use them. The tolerances and balance can be all over the place so I don't think they would be of any benefit.

I don't think you are having as much a backlash problem rather a problem with the material. I find that to sew thin stuff particularly with ripstop it can become a real balancing act in getting the bobbin thread to properly set. I put the problem down being caused by the makeup of the ripstop. I find some things that are less then 4 to 5mm in thickness a bit of a chore with the 1541S so for those items I use the less capable 1181n. A good reference to show how the 1541 reacts with light, medium and heavy fabric take a look at youtube.com/watch?v=4JES-2I7h3o versus the less capable 1181N with the same material youtube.com/watch?v=IKJuKTrjsbw&t=300s

kgg

I will checkout the links you posted.

I am 99% sure this is a backlash issue. I didn't mention this previously, my bad. When I am sewing constantly I have little to no issues. My problem is when I stop sewing. The stitch will be fine until I stop, when I begin sewing again the first stitch or first few stitches will pull the bobbin thread to the top. As far as I'm aware this is thread backlash. Maybe I am wrong. I hope this clears things up a bit.

I will post in this thread on Monday more details with my current setup including thread guide path.

Kind Regards