Machine stitching failing consistency Adler 669

[Manuel55]

Hi,

I am having serious troubles (3 mechanics visited, Emailed Producer 7 times forward and back, spend almost 10 days in trying) to set up my Adler Duerkopp Eco 669 to sew consistently.

I tried different threads (Gutermann 20, MBT 5 & 8) Different needles: 120-160 points: D/VR/S/LR Schmetz.
Different settings on all possible places.

However the problem stays, just sometimes the knots go up or down accidentally.

I am sewing vegtan leather (rather an 8 on the scale from 1-10 in stifness).
2 Layers of 2 mm thickness, straight lines mostly.

I cleaned most parts visible, to be sure its nothing stuck, and set the needle to be in the supposed to be correct position.

The tension on the bobbin and on the upper thread i tried in 100 of different settings, but nothing was 100% working.

What i discovered, which might lead to the cause of all problems:

If I stitch by motor, I can set up the stitching to be nearly flawless completely. But if I switch then and turn the wheel by hand, I get a much higher probability of the knots forming on top of the leather.

 

If anyone is out there, who has a good idea, what might be the cause, and where I could keep looking, I would be so thankful.

[kgg]

26 minutes ago, Manuel55 said:

I tried different threads (Gutermann 20, MBT 5 & 8) Different needles: 120-160 points

I am not overly familiar with Gutermann thread other then it is now called A&E Gütermann but if you are using:

1) a 134-35 size 120 (#19) needle you need to use a V92 ( Tex90, Tkt 30, M40, 40) thread,

2) a 134-35 size 160 (#23) needle you need to use a V138 (Tex135.Tkt 20, M20, 20) thread

Your machine should be able to handle a top thread size of 15 (V207, Tex210,Tkt 15, M20, 20) with a max bobbin thread size of 20 (V138,Tex135, Tkt 20, M20, 20).

A couple of good charts for what needle size to use with what thread size:

1) 5 Thread Size Comparison Chart 2-4-10

2) https://www.tolindsewmach.com/thread-chart.html

Your problem maybe that you are using a needle one size up from the recommended size in thin leather so the hole maybe to large for that thread size; if you are using a polyester thread the knot may have an easier time slipping up to the top particularly during hand wheeling the stitches as the amount of needle pressure maybe not as constant as that of when the machine is motor powered. Just my thoughts. Why are you hand wheeling long seams is it because you are using a clutch motor ??

kgg

 

[Manuel55]

Thank you for your answer!

I am using at the moment in this particular trial set:
A&E Gütermann Tera 20 (Bottom and Top), and tried mostly with needles: Schmetz 134-35 Size 120/130/140 LR, VR and D

This should be the correct sizing as I understood.

I am only using hand wheeling to identify the problem.

Mostly I am sewing with motor, where sometimes a single knot might appear up and down, which is the real problem for me.

To track the issue I started hand wheeling to slow things down, and then the problem of the knots on the Top side appear.
So my wild guess was, that the motor stitching, somehow, is covering the issue mostly, and by hand wheeling it shows more.

[kgg]

What size of spool of thread are you using 8 oz (~226 grams) or 1 lb (~ 453 gram) as sometimes the small sizes of thread particularly black have caused problems.Would it be possible to take a couple of photo's of your thread path from the thread spool to the needle as well as a photo of how you have the spool of top thread set up. To get thread properly coming off the spool there should be at least 2 1/2 times the height of the thread spool between the bottom of the spool platform to the spool thread guide.

kgg

[Manuel55]

HI, I made some pictures, following the thread.

 

What I noticed:

When I hand wheel while sewing, and I get to the timing, when the machine is about to pull the top thread from the spool.
The slower is move the hand wheel, the less thread i receive from the spool. When I turn the hand wheel in that position quickly, it get the supposed amount of thread.

So i tested by hand, and it looks like there is an initial resistance to the thread which disappear slightly after pulled over that resistance.

I am not sure, if this is supposed to be normal, but it kind of would explain, why there is an issue with hand wheeling,
as the bobbin thread can be pulled with a great consistency.

The tension after the last disc feels generally slightly inconsistent, but I am not sure, if this is objective.

I had a look on the tension discs, and they seem to be without any marks or anything else.

Maybe there is a material, that can be used instead of the metal, to decrease the initial resistance?

 

[kgg]

2 hours ago, Manuel55 said:

HI, I made some pictures, following the thread.

I have a couple of suggestions:

1) Thread:

i) Top thread: Change to a larger size of spool preferably a 1 lb (454 gram) spool rather then the mini (domestic machine) size spool you are using. You should find a more consistent tension of the unwinding of thread. I find having the thread entering the first guide as close to the horizontal plane as possible rather then the steep downward angle like you have really helps.

ii) Bobbin thread: Do the drop test on your bobbin to ensure proper tension.

2) Thread Guides:

i) At the first thread guide: rethread the first guide so the thread enters the middle hole then loop thread over the top of the guide and enter the thread from the rear of the guide through the left most hole. Also do the same for when you are winding a bobbin. This should give more of a consistent amount of thread being unwound from the spool.

ii) Move your thread take up guide so it indicates a larger number, I would try position 3.

iii) I would rethread the thread through the bottom hole in the takeup arm rather then the top hole.

 

kgg

 

[Manuel55]

I tried the suggestions, except the bigger spool, which I don't have currently.

 

When I move the thread guide up to number three, the thread spring is moving in a way, it is not supposed to be.
As far as I understand it should only move 0.5 mm when the thread is passing the biggest part of the Bobbin.

But if i set up the thread take up guide to 3 and use the bottom hole of the take-up arm, the spring gets under tension way more.

It feels from an uneducated guess, that there is a more direct issue. Maybe something, how the thread goes around the bobbin case?

I made two videos:

 

 

 

 

Edited February 17, 2022 by Manuel55

[kgg]

1 hour ago, Manuel55 said:

I made two videos:

 

I think you should send those video's to DURKOPP ADLER and ask for there advice on what is happening with your thread take-up lever.

kgg

[shoepatcher]

OK  I have a DA 669 eco.  great machine.  The one problem I had since I sew mostly with #138 is this.  Adler borrowed the entire hook from their 367 machine since it was a horizontal hook in the flatbed.  The largest needle you can use with it is a 150.  Try finding that size.  normally #140.     I use a titanium coated #160 for what I sew.  To use it, I had to remove the bobbin case basket.  I took both  carbide and diamond bits and enlarged the slot the needle goes down thru.  i then went over it with silica carbide flat Mitchell cord to polish it up.  I now can sew with either a #160 or 180 needle.no problem.  No more frayed or cut thread.  Why DA did not enlarge the slot from the beginning is beyond me.  The 669 silver line with trimmers has a larger slot in it to accommodate the #180 needle.   If you sew with #138 thread, you need to do this.

I also think that leather made be a bit hard for this machine.    for the hell of it, wet the leather and try sewing it and see if you still have tension problems

glenn

Edited March 12, 2022 by shoepatcher