Adler 167 Bird nest

[snipenz]

Hi everyone,

New to the group but thanks for letting me join. I read through some old posts but can't seem to find a solution to my problem.

The issue is that I get bird nests on the underside after a back-stitch.

Here is what I've got:

Machine: Adler 167-373 in very good condition. I converted the machine to a 550W Chinese servo motor and love it.

Material: canvas, thin leather (chrome tan, about 1mm), thick leather (chrome tan, up to 2.2mm) and occasionally denim

Thread: Coats Dabond OT, Tkt 25 (V92, Tex 105)

Needle: Schmetz leather point, NM120 (size 19)

The issue: The machine sews like a dream and is a pleasure to use. I do hold the both threads when I start and let them go when I'm sure the stitches are "locked". However, when I reverse for the back-stitch no problem. It sews in backward direction without issues.  When I release the lever and go forward again, every time a coconut I end up with a bird nest on the underside and the safety clutch goes out of kilter. It only happens when I sew forward again over the previous stitches. It does this with all material. It also happens when I lift the presser foot and move the material back. 

I am convinced that it is caused by the top thread but can't figure out why. At the moment I use red in the bobbin and black as a top thread. Same thickness. The bird nest is black, every time.

My temporary fix is pulling the top thread through to the underside an double knotting the ends. It works, but is very cumbersome and of course time consuming.

From what I read, general consensuses to my problem are tensions, but I tried all sorts and nothing works. I have not altered the pressure on the presser foot as yet but doubt that this could be the cause.

There seem to be many clever and experienced people here and I hope some kind person can help me fix my problem.

Many thanks for reading to the end and for any possible advice .

Rene

 

 

 

[kgg]

1 hour ago, snipenz said:

but I tried all sorts and nothing works.

I wonder could this be caused by a bobbin case tensioner spring gone weak, over tightened and bent or a groove worn in??

kgg

[snipenz]

Cheers for you suggestion. Today I removed the bobbin case and checked the tension spring. It appears to be okay and still has a nice bow and no visible grove.

I sewed about 10cm and then the same distance in reverse with no problem. As soon as I let the reverse lever go to sew forward again, the machine spat the dummy. Bird nest on the underside and definitely from the top thread.

[CowboyBob]

2 hours ago, snipenz said:

Cheers for you suggestion. Today I removed the bobbin case and checked the tension spring. It appears to be okay and still has a nice bow and no visible grove.

I sewed about 10cm and then the same distance in reverse with no problem. As soon as I let the reverse lever go to sew forward again, the machine spat the dummy. Bird nest on the underside and definitely from the top thread.

Yes,your going in the right direction,birdnesting underneath is always the top thread.Either it's too loose or not threaded correctly,try tightening the top tension 1/2 turn @ a time until it goes away.

[snipenz]

Hi Bob, thanks for your comment. You are correct. I tightened the upper tension half a turn at a time and there is a definite improvement. I thought I had the tensions right but it is definitely better now. I'll keep trying to sew now although the upper tension seems super tight. Time will tell.

Thanks again.