Irregular stitches Adler 669

[Julien]

Hello,


thank you very much for yours advices in this forum .

I read you passionnatly.
I repart, and work with some beautifull sewing machine also

So, yet, i would ask to you somethings


A)
I have an adler 669

and it is painful to fix it... my stitches are irregular
as you can see :

 

I removed :
1) bobbin case (for new one, with good spring)
2) new bobbin
3) new hook
4) cleaning each tension disk
5) when i pull below string, there are not too light tension not too hard tension, without irregular tension (good slide between metal part and string)
6) Tension top and below arenot too much
7) Tension on the top, not irregular also
8) check Spring
9) All is clean
10) Leather completly homogeneous
11) Thread that is good wound on the spool.

i have other 669 adler, with the same string (size) and the same needle, with very good result
i really don't understand with i have this result...

i read also the 16 advices from Wizcrafts (thank you for it) but no results...

have you got an idea ?

Thanks a lot to read me
Julien

Edited August 27, 2022 by Julien

[Constabulary]

Without knowing your thread and needle size - I would try a 1 size larger needle

[trash treasure]

We had a cone of bad thread once, that would cause that - Uneven thickness, I guess.

[Julien]

Thank you for your anwsers !
trash treasure, how can i control my thread before using it ?

have a nice day !

[trash treasure]

As far as the thread goes, that may not be the problem here. I mentioned it, as something to check, when all else fails  :~)

We've gone through a lot of thread in our shop, and I only remember one spool that was bad that way. It was supposedly bonded polyester, but obviously poor quality, as it fed through the tensions weirdly - Not much to do about this kind of thing, except to try and buy good quality.

[Wizcrafts]

On 8/27/2022 at 2:24 AM, Julien said:

5) when i pull below string, there are not too light tension not too hard tension, without irregular tension (good slide between metal part and string)
6) Tension top and below are not too much

FYI: I sometimes find the if I get irregular stitching, tightening both the top and bottom tension may help stabilize the position of the knots. This may require moving up one needle size, or not. Some leathers are tougher than others. I have had bridle leather that actually had portions of rawhide inside. It was so tough that it broke my roller knife blade! I'm not saying yours has rawhide, but it may have uneven densities in different places on the pieces you are sewing.

[Julien]

Thank you Wizcrafts
So, i did :
adler timing hook
push a bit lighter the foot
and a bit stronger (as you propose) the tension
The result is better 

thank you all for your advices