Kobe 1341 not bringing up knots.

[pattysoup]

I am having a terrible time with stitches. pics attached. any ideas. When I adjusted the tension disk - looser or tighter - the bottom stitch remains the same. No difference.

machine kobe 1341

 

[Wizcrafts]

@pattysoup

It is uncool to inject a totally unrelated question into somebody else's ongoing topic. In this case, you entered a discussion about a Landis 3 needle and awl machine with a question about an entirely different type of machine. I have split it into a new topic. Although your brand of machine is mostly unknown to many of us here, the model number suggests that it's a clone of a Juki LS-1341.

Upon looking at your photos my first thought is that your needle size is too small for the thread. It is also possible that the machine cannot properly handle the size of thread you are trying to use. Please fill in the blanks of the needle and thread sizes and show a picture of how you have threaded the machine.

Edited March 18, 2021 by Wizcrafts
I corrected the model number.

[kgg]

The Kobe LS-1341you have is a clone of the older Juki LS-341. I have a couple of questions that may narrow down the problem.

1) What size of thread are you using for the top and in the bobbin. It appears to be V138 or V207 for the top thread. I am going to assume it is V207 on top and V138 in the bobbin as the bobbin thread appears to be smaller. For V207 thread the minimum needle needs to be a 135x17 #24 needle in fabric or 135x16 #24 in leather. But you may have to move up to a #25 needle in sticky or thick stuff, which your machine is not rated to accommodate. If the needle doesn't make a large enough hole to haul the top thread and up back up you can get the straight bobbin line. 

2) Top tension and thread path. If possible could you post a detail photo('s) from the top of the spool to the eye of the needle.

3) Bobbin tension not properly set. Have you done the bobbin drop test? Your machine is only rated for V138 in the bobbin.

4) Presser foot tension may need to adjusted slightly.

As a note I run V138 top and in the bobbin in my Kobe LS-1341 most of the time.

kgg

 

[Uwe]

Those loops at the bottom indicate to me that the thread snags somewhere during the stich cycle and the machine never gets a chance to pull the knot tight. Usually that has to do with either hook timing, burrs, or the bobbin case opener function.

Double-check your thread path and do a few very slow hand-turned stitches while observing how the thread gets wrapped around the hook. If the thread snaps or snags anywhere, that’s what you need to fix. If the machines pulls more thread form the spool in the middle of the stitch cycle, that’s a sure sign of trouble. The machine should ONLY pull thread form the spool when the thread take-up lever is at the very top of its movement.

 

Edited March 18, 2021 by Uwe

[RemingtonSteel]

Although my fellow colleagues above know far more about various sewing machines than I ever will, I have a question I would like to interject.  I could be way off base here, but are you sure you are adjusting your tension discs and not the switch length dial?  The reason I ask is, when looking at your photos, I see that the stitch length is changing not the tension?  Just an observation.

[pattysoup]

I am very grateful for all the help. Will be tinkering tonight. Just watched  utube Adjusting the walking foot -  special shoutout to Uwe.

[DonInReno]

When the stitch length gets shorter and bottom thread looks like that I tend to think the bobbin tension (or binding somewhere in the bobbin thread path) is so tight it’s preventing the material from feeding correctly.  

[kgg]

Thank you for the photo's on the thread path.

What I see:

i) In the first photo you are missing the felt pad that holes the thread against the back part of the squareish guide just before the thread goes down to the needle guide. Lost of tension at that location of top thread.

ii) This is I think your main problem. You say you are using a "125 size 20 135 x 17 DP x17 " the needle needs to be a #23 needle for V138 or if the material is sticky or tough you need a #24 needle. The needle hole is just to small to pull the top back up with the additional V138 bobbin thread so it lays flat. The #20 needle is good for V92 thread.

As a note the easiest way to make sure the top thread is seated as far down in between the main tension disc's as possible is to have the needle up to it's highest point away from the feed dog and then rise the pressor foot up and lock it by using the pressor foot lever at the rear of the machine so the tension discs release from each other then thread top thread through. Sometimes the thread may look like it is between the discs but isn't seated right in the middle of them.

kgg

[Constabulary]

Agree with KGG - try larger needles sizes!

[Wizcrafts]

On 3/17/2021 at 11:09 PM, Wizcrafts said:

Upon looking at your photos my first thought is that your needle size is too small for the thread.

I still believe this to be true.

[DonInReno]

Yes 20 is too small a needle.

[pattysoup]

Hi

I filmed a few very slow hand-turned stitches. 

I have been tinkering with the tension and no matter how tight or loose I make the top thread and bobbin, the stitches stay the same  - the top tension is too loose and the bottom is too tight.

Needle size - Organ RTW 21

Thread Cansew Bonded Nylon 138

Leather scrap precut belt from Tandy but same results no matter the leather

Not sure what part of the machine to adjust (besides the thread tension) to fix this issue.

Has anyone else experienced this problem - clone 341 cylinder 

Best regards

 

[kgg]

My two cents worth:

1. The needle Organ RTW 21 is too small for V138, I suggest you use a #23 or #24 needle.

2. The link ( https://www.youtube.com/watch?v=PIKml4yGLSc ) is not for the Kobe 1341 but it has a similar top thread tensioner system. It is one of the better ones as far as detail goes and if you follow the way it is done you shouldn't have any other top tension problems.

The video shows the top thread going over the small post located on the right side of the discs of the top thread tensioner unit. That point of having your top thread go over the post before going to the take-up spring disc has been a topic of much contention. I happen to fall into the category of believing it should go over the post. My reasoning is  i) if the thread will not go over the post and sit properly behind the post the thread size is to large for that machine. ii) provides more surface contact area of the top thread between the two tensioner discs. I have done it both ways on my machines with one being a Kobe LS-1341and find I get more consistent tension but that just maybe me and the sizes/type of thread I use.

3. Once you get the thread path and tension settled out you should never have to manually thread the top thread of your machine again when changing size or spools of thread.

i) Cut the old thread just above the top of the old spool and tie the new thread to the old thread that is still threaded properly through to the needle,

ii) Lift and lock the pressor foot in the up position

iii) Pull the old thread out of the eye of the needle and pull on the old top thread which will pull the new thread through.

iv) Cut the top thread above the knot of old and new thread

v) Thread the new thread through the needle.

Best of Luck,

kgg

[Constabulary]

I would try a # 22 / # 23 needle for 138 thread + to me it looks like your bobbin case opener needs to be adjusted (thread seems to keep hanging a little bit). Your check spring may need adjustment as well (more travel).

Do you have a manual for your machine? Usually they have hints for adjusting, threading, needle thread chart and so forth.... get one if you don´t have one.

Edited April 13, 2021 by Constabulary

[pattysoup]

Thank you all for responding.

Constabulary -I adjusted bobbin case opener  Result: helped but problem not solved completely 

Kgg - going to see Chris this afternoon will update later today

[kgg]

I would definitely be interested in learning what the source of the problem is.

kgg

[Uwe]

I still think the issue has to do with hook timing and not needle size, although it may be a combination of factors. 

It looks to me like the hook arrives a little too late at the needle. This causes it to be slightly out of synch with the the take-up lever movement. The still frame below shows the moment where I think more thread gets pulled from the spool. The thread is taught everywhere and the check-spring is overpowered and maxed out. The thread take-up lever has already started going back up at this moment. At this point it does not matter what tensions setting you have dialed in, thread will get pulled from the spool no matter what. Every millimeter of extra take-up arm movement pull two millimeters of extra thread from the spool. That excess thread will later prevent the knot from getting pulled into the material.

 

This still frame below is taken at the moment the needle is at bottom dead center. The tip of the hook appears to be near the 6:30 o’clock position. It really should be near the 7:30 o’clock position (needle is at the 9:00 o’clock position)  

 

I made a quick handheld video showing the stitch cycle on my Juki LS-341 in a slow motion hand-turned stitch. Hopefully it will allow you to compare my stitch cycle timing with your machine. 

 

My recommendation would be to advance hook timing by about “5 minutes on the clock face” and see if it helps.

Edited April 13, 2021 by Uwe

[pattysoup]

Changes made today - Replaced bobbin case. Thread Cansew Nylon 138 and RTW organ 21needle

Adjusted hook timing 

Result - Top and Bottom stitch looking better.

There is a clicking noise when I reverse stitch. Reverse Stitch looks pretty bad.

 

 

[Uwe]

That clicking or snapping noise in reverse sounds like the thread getting hung up on the hook’s cast-off gib as the thread is being pulled up. Advancing the hook timing a little more often fixes that.

[pattysoup]

Thank you, Uwe. Will do - advance the hook timing a little more. 

[palvim]

On 4/13/2021 at 8:08 PM, Uwe said:

I still think the issue has to do with hook timing and not needle size, although it may be a combination of factors. 

It looks to me like the hook arrives a little too late at the needle. This causes it to be slightly out of synch with the the take-up lever movement. The still frame below shows the moment where I think more thread gets pulled from the spool. The thread is taught everywhere and the check-spring is overpowered and maxed out. The thread take-up lever has already started going back up at this moment. At this point it does not matter what tensions setting you have dialed in, thread will get pulled from the spool no matter what. Every millimeter of extra take-up arm movement pull two millimeters of extra thread from the spool. That excess thread will later prevent the knot from getting pulled into the material.

 

This still frame below is taken at the moment the needle is at bottom dead center. The tip of the hook appears to be near the 6:30 o’clock position. It really should be near the 7:30 o’clock position (needle is at the 9:00 o’clock position)  

 

I made a quick handheld video showing the stitch cycle on my Juki LS-341 in a slow motion hand-turned stitch. Hopefully it will allow you to compare my stitch cycle timing with your machine. 

 

My recommendation would be to advance hook timing by about “5 minutes on the clock face” and see if it helps.

I am having similar issues and I have the same machine just a different brand. I had got the thread jams and all kinds of issues with the bobbin case being stuck etc. Somehow I managed to unjam and get the machine sewing again. This video is so helpful. I see that my hook point is more at 11 O' clock rather than 12 O' clock at the lever being in its highest position. I am wondering how to fix the hook point to be at noon. Could you point me to some instructions Uwe? Thanks. 

[Uwe]

(I can’t remove the accidentally embedded/deleted video above, please ignore)

The Juki LS-341 manual is the main reference for adjustments. Here’s the full PDF:

ls341n.pdf

Here’s the relevant section:

 

The picture below shows the three screws that hold the hook driving gear to the shaft. Follow the manual for adjustments and screw tightening sequence.

Things to keep in mind:

Keep the teeth of both gears engaged at all times. The gears are very likely matched pairs, meaning they are made to mesh with specific opposing teeth for optimal smoothness. 

Push the driving gear gently to the left to fully engage the teeth before tightening the screws again. If the teeth are not fully engaged (touching), you will have play in the driving gears, meaning you will be able to wiggle the hook back and forth. Ideally the hook should nice and snug with very little play.

This hook driving gear design on the Juki LS-341is nearly the same as on the Adler 67, the only real difference being the number of clamping screws on the gear itself. The two machines are very different in many aspects, but this driving gear detail and how to adjust it is very similar. You can watch this video on hook timing for the Adler 67 to get an idea of how those gears work, starting at the 3:50 mark.

Note: The Adler uses only two screws, the Juki uses three screws and a specific screw tightening sequence!

 

 

Edited April 20, 2021 by Uwe

[DonInReno]

Patty,  Maybe bobbin tension was talked about more and I missed it - at the risk of beating the dead horse here's a way to eliminate that as a cause.   Because bobbin adjustments are so subjective, it's not uncommon for us to be helping someone who thinks they have adjusted the bobbin tension correctly only to find out it's way too tight.

I'm assuming since the bobbin is loaded from the top that the bobbin case is built in and only the bobbin itself is removeable?   Over a discussion forum its really hard to describe and judge the correct tension since the traditional way of judging a starting tension involves a removable bobbin case hanging from the thread tail.  

I measured that thread tension and it's about 30g.   Putting 5 loonies or 5 US quarters in a baggie and hanging it by a thread gives you an idea about the amount of tension you should have coming out of your bobbin tensioning spring.  4 loonies is not enough - that's the equivalent of the bobbin case falling to the floor on it's own.  7 loonies is definitely too much.

If nothing else this will help those of us who worry bobbin tension hasn't been ruled out. :-)

You've been sewing heavy fabric with this machine - does the bobbin thread pull up ok in the fabric?  A picture of the bottom thread in fabric would be nice.  (this helps to rule out needle size as being the culprit since needle size isn't as big a deal with fabric - if the stitch looks great in fabric and crappy in thick leather that suggests needle size is still too small in leather.)

Is this the same machine that says made in Japan, but the box said made in China?  I have a few parts with similar pedigrees - I have no idea if they are Japanese, were assembled by Japanese, were inspired by Japan, or are just mislabled.  :-)

Hang in there - the more things you can rule out the closer you're getting to smooth sailing!

[DonInReno]