Bought an Adler 69! Basic Questions...

[arz]

I was able to get the reverse stitch length very very close. It is stitching good. Getting the thread tension correct was not too bad. Still having fun

Now to polish the feet just a little more to help reduce marks on vegtan, wait for my parts to get here, and get busy! My wife is ready for me to sew some of her purse designs

[arz]

Update: I have installed the missing parts and edge guide.

But...I am having a lot of trouble getting a consistent stitch.

Problem 1). I get it adjusted good and it will stitch for a few cm (inches) and then a knot (most of the time on the bottom) will appear. It seems random. It will happen on a long run, or after I stop, no difference. Softer leather seems to sew much better. English bridle is not bad. But my Italian vegtan...I just cannot get it set right. I have gotten some beautiful stitches, but I cannot trust it to stitch more than a few cm before a knot will form at the bottom (more likely) or top.

Problem 2.). If I stitch 2mm of leather, and then get to a part that is 3mm, a knot will show on the top of the 2mm part just before the 3mm part. How do I get consistent tension on multiple thickness? Say only 1--3mm difference between layers?

I have tried everything I can think of and have read every post I can find. 

So....I had a local mechanic look at it and he just said buy a new machine  He did not want to play with it. He did say that one of my problems was the bobbin might be spinning when I stop...or....I am losing tension at times. He recommend I put a small piece of fabric behind the bobbin and a drop of oil. I tried that and it made no difference. I could try to find a bobbin case with a break/spring in it....

I am using Serafil M20 (#135) thread. I have tried 130, 140 and 150 LR needles. 

 

Here are some things I have tried:
1. Different needle sizes
2. Rethreaded, tried threading through more/less posts (thread is new)
3. Make sure thread cone is thread through center eye above it
4. Playing with bobbin/upper tension 
5. Make sure bobbin is wound even, not too tight or lose etc. (might still be a problem)
6. Adjusted reverse stitch length
7. Adjusted take up leaver/spring
8. Smoothed some burrs on the bobbin case, and other parts of the thread path
9. Tried putting a small piece of fabric (from a shirt tag) and a drop of oil behind the bobbing. To stop it from spinning.
10. New, steal bobbins from Collage Sew
11. Removed pin that releases tension when you lift the foot. I release it only by the hand lever.
12. Increase foot tension. It is quite a lot it seems to me.

Here's some photos. I can post a video on YouTube later if that will help.

Thank you for any help you can give! -Adam

Photo above: Top thread is top stitch, next is bottom stitch

[arz]

My Adler is working much better. I "think" I have it adjusted good. For those who may read this here is what I did:

1. I went through the service manual at lest twice adjusting everything according to spec. There we a few settings just a little off. From what I have read things must be set pretty good.  

2. The take-up spring I think was the key to my problem of random knots. If it is set to low or too high a knot would form, often after I stopped. 

3. Also getting the bobbin wound as perfect as I can. I am still having trouble getting the bobbins to wind perfectly even every time. I hope to get better at this.

4. Using the correct needle size. I found with my Italian vegtan a size 140 LR needle is perfect. With softer leather a 130 or 140 works very good. The 150 needle seemed too large and the knot I think was too lose in the hole. I am using 2-5mm of leather total with Serafil M20 (#135) thread top and in bobbin.

I guess you just have to spend hours learning how to adjust these machines (I about gave up!). The local mechanic did not want to mess with it so I just had to learn. After working with it for hours (too many!) I am starting to understand it  

I "hope" I can now start putting it to good use!

I do still have a few problems. My new KH feet are not working well. The needle will not line up with the hole in the center foot. I think the needle hole in my needle bar is "just" a little too large, this allows the needle to move to the left about 1.0-1.5mm when I tighten the screw. Oh well....