Kobe 1341 not bringing up knots.

[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.