Adler 67-GK373 stitch length and reverse

[andru]

Hello! First time posting, long time lurking as a guest. The amount I've learned from these forums is invaluable, but for the first time I have a query there doesn't already seem to be a thread about!

I've recently aquired an Adler 67-GK373 which after some adjustments is sewing well. The stitch length lever was so sticky that it was locked anywhere it was moved to, rather than springing back down, and the stitch length locking bolt was seized in the eccentric nut housed in the casing. I've resolved both these issues with oil and patience, but it's brought up some issues and questions I feel a bit out of my depth with.

According to the exploded diagrams of this model, the stitch length bolt should have a collar on end - circled in red in the attached picture, part #067160583. Mine is missing. It's absence doesn't prevent the mechanism from working, but since it is this part of the mechanism which makes contact with a cam inside to set the stitch length, I'm not certain if I can replace it with any collar with the right internal bore, or if the external diameter is critical. I can't think why it would be critical, since it's not a particularly fine mechanism which only depends on how far the bolt is screwed in, and appears to be working ok without it at all.

For now I've adjusted the eccentric reverse stitch length adjustment nut so that the reverse and forward stitch lengths match with the bolt as it is, sans collar.

Which introduces my first issue...

The max reverse stitch length appears to be about 4mm - contrary to the max forward stitch of 6mm according to the brochure, and 7mm as measured on my machine - and I can't see any way to adjust it. I can't find anything in the brochure or manual for this model that suggests that the reverse is limited to 4mm, but I have come accross this mentioned in a thread somewhere on this forum (which I now can't find for the life of me!) and in a YouTube video explaining how to adjust the stitch length on a 167

Could it be related to the missing collar? It doesn't seem like it should be but...? Does anyone know if the machine is for some reason limited to a max reverse stitch of 4mm, or if there is a means to adjust it I haven't found?

 

My second issue is that unless I toggle into reverse at exactly the right moment, when the needle is right at the bottom of it's cycle, then sometimes the bottom thread tangles, and sometimes even jams up inside the hook. I can't reproduce it reliably enough to know the exact circumstances under which it happens, so I'm hoping somebody might have some gem of knowledge about some perculiarity with the machine I need to be aware of, or something I can adjust to prevent it. At the moment I can only reliably back tack by hand spinning the wheel, as my servo just doesn't go slow enough to hit the reverse lever at the right time without risking ruining my run. Not a huge deal, but it'd be a nice problem to solve.

[Michiel]

Hi andru,

I have the same machine (more than one)

i think you should adjust the excentric on the (top) mainshaft.

what i usual do is put the needle an the hook in the postion that the hook just is about to pick up the thread

and than move the reverse handle

if the needle bar moves i adjust the excentric so that the needlebar does not move when going up and down with the revesre handle

good thing is : the timing in reverse is now the same as in sewing forward

the better thing is, with most of my machines the forward and reverse are more or less the same.

fine tuning is possible with an excentric on the front side (but its rare you need to do that)

 

but first of all best is to follow the service manual step by step.

Did you find the service manual on internet?

kind regards, michiel

 

Edited November 14, 2021 by Michiel

[Michiel]

 

067 16 001 3 is the excentric you need to turn a litle

[Michiel]

The forward and reverse handle mechanisme has an hidden way to adjust forward en reverse stitching

it is only in de 169service manual but its the same on 67 167 69 etc

i did only find a version in german

https://www.duerkopp-adler.com/commons/download/download-text-attachments/Vintage_Manuals_Adler/Serviceanleitung_169_DE.pdf

 

its on page 18-19

 

 

[Michiel]

Part 69 is excentric

you can turn it by a special tool (64) or you use two nails….

[trash treasure]

Thank you, Michiel !

I have the same problem with a 167 (Timing changes in reverse) , and it's been driving me nuts - Now maybe I have the answer :~)

[trash treasure]

Success !

I followed Michiel's suggestion to adjust the upper arm eccentric, and it worked 100% - The timing now stays exactly the same, forward and reverse.

I did find that I also had to adjust the feed dog lift eccentric under the bed, to bring the feed dog back up to proper level, after the stitch timing was correct, but now the machine sews PERFECTLY, forward, reverse, at any speed, with any material thickness - Thanks again !

[Michiel]

Thank you

this is not from the 167 service manual (but i think it was mentioned in other manuals)

i do it often after hooktiming (and check the other adjustments from the manual after it)

i think its not a bad idea for  other brand  triple transport machines too and wondered if more people do it that way…

[andru]

Thank you Michiel! I never got any notifications to replies, so my apologies for not replying sooner.

On 11/14/2021 at 1:52 PM, Michiel said:

i think you should adjust the excentric on the (top) mainshaft.

what i usual do is put the needle an the hook in the postion that the hook just is about to pick up the thread

and than move the reverse handle

if the needle bar moves i adjust the excentric so that the needlebar does not move when going up and down with the revesre handle

good thing is : the timing in reverse is now the same as in sewing forward

I was using the method as described in service manual, and I succeeded in adjusting the reverse to match the forward stitch, but the maximum reverse stitch length is about ~4mm, so a forward stitch of 7mm will have a reverse of 4mm.

Your advice to use the eccentric on the top shaft is something I've not tried, so I look forward to try that (as soon as I've fixed my broken hook gib!)

Also your method of positioning the needle and trying the reverse handle is great! I tuned mine with a lot of trial and error