Set up of Juki LS-1341 type machine

[DonInReno]

Hopefully it’s an easy fix and you’re up and sewing soon!

[chrisash]

Get a fixed quote prior to giving them a fee hand to upgrade, I would just ask them to do there testing after repair on the 138 thread before mentioning any upgrade

 

[Uwe]

I still think you should try to advance hook timing. It may make a big difference. After my previous recommendation, you just said hook timing looked fine as it was. What I’m a asking you to do is to purposely advance hook timing away from that “fine” adjustment. You may just end up with a “perfect” adjustment. On occasion, the by-the-book setting is just the starting point. Then you make small adjustments until everything works smoothly - I do this quite often. Picking up the top thread loop is only one of the functions the hook timing tries to get right. There are several other functions that are also affected by hook timing. To get all of them working just right at the same time, you may have to vary slightly from the original adjustment.

Don’t view the adjustments shown in the Juki engineer’s manual as absolute commandments. Your machine is a copy and it uses a different hook. Some adjustments may simply be a little different for your machine.

That change-over to the 1341 configuration you’re contemplating seems like a major undertaking, one I personally would be very reluctant to sign up for. I’m not sure it will be worth the money you’ll spend to have a mechanic do all that work. It’s like accidentally buying a car with a manual transmission, then asking the dealership to install an automatic transmission. While technically possible, it’s not an economical solution. It’s generally far cheaper and better to trade the manual car for an automatic one (or learn to drive a manual.)

Edited April 24, 2021 by Uwe

[palvim]

Hi Uwe,

I will not do an upgrade of the hook system. I guess in that case I'll have to sell the machine. However, I have advanced the hook timing and it definitely is stitching better. When I stitch straight I'm getting a very consistent stitch. 

On curves where I turn the flywheel by hand, the stitch gets all wonky. I am guessing this time it's the man behind the machine that is the problem. Is there a specific technique to do turns and sharp corners without missing the tensions? 

[Uwe]

For turning corners, I recommend stopping the machine with the needle in the material, ideally right after the needle enters the material and well before it reaches the very bottom of its movement. There’s some bad advice floating around on this subject.

Also, lift the feet just enough to pivot the material, but not so high that the thread tension release activates.

[palvim]

I had one question about the machine set up that I have now. The guys I purchased the machine from say that the machine can definitely sew 135 thread. So I read through the manual again and I noticed something strange. 

The bobbin case latch on both the ls-1340 as well as ls-1341 are pointing down. On my machine it's pointing up. Is that strange? 

 

[palvim]

So I was at the technician today and the machine seems to be working quite fine so far. Touch wood :-)

The first thing he noticed that the hook was too far away from the needle. So he had to push the hook to the left so the hook was almost touching the needle to pick up the thread loop. I think that was the one that actually fixed the issue with uneven stitches. 

He also thought my bobbin tension was a tad bit loose so he tightened it. 

He also adjusted the presser foot which was not on level with the center foot when the needle should just enter the leather. 

His suggestion was also when I use 2 layers of 10oz leather to use 160 needle for the 92 thread. And 140 was fine for thinner leather. 

Before leaving he also taught me on the process of setting tension. His suggestion was that I set tension such that I see the bottom thread popping up on the top and then loosen it until it disappears enough into the leather. 

All this is probably basics but for a self taught person I thought it made a lot of sense. And this structured way of setting tensions was very good tip to follow. 

I came home and did very fine adjustments to make sure that the thread was leaving the throat plate smoothly. This made turning the flywheel a little easier.  

Moral of the story for me was N E V E R apply force on the machine when the thread and material is jammed. But I guess I learnt a lot from all you guys about adjusting the timing, needle to hook relationship, thread path on the throat plate etc in the process. In the end it was about $150 worth of lesson :-)

Thanks a lot @Uwe for patiently helping me on this issue and replying to my queries so many times. 

[Wizcrafts]

32 minutes ago, palvim said:

His suggestion was also when I use 2 layers of 10oz leather to use 160 needle for the 92 thread. And 140 was fine for thinner leather.

I take issue with this recommendation. That size needle pokes a hole that is much too large for the combined size of the overlapping lockstitches. I normally use a #19/120 needle with #92/T90 thread. Sometimes I use a #20/125 for difficult material or sewing through double sided tape. I would not use a #23 needle unless I was sewing with #138 thread, top and bottom and the leather is medium to hard temper.

[DonInReno]

2 hours ago, palvim said:

So I was at the technician today and the machine seems to be working quite fine so far. Touch wood :-)

That’s great news!    It must be a relief to be able to concentrate on sewing and not fighting with the machine.   :-)

[palvim]

Absolutely @DonInReno!! 

6 hours ago, Wizcrafts said:

I take issue with this recommendation. That size needle pokes a hole that is much too large for the combined size of the overlapping lockstitches. I normally use a #19/120 needle with #92/T90 thread. Sometimes I use a #20/125 for difficult material or sewing through double sided tape. I would not use a #23 needle unless I was sewing with #138 thread, top and bottom and the leather is medium to hard temper.

I'll just try and experiment and see which needle works based on the stitch consistency and look. Hopefully I can continue to use 140 needle that works very well today.