Durkopp cl 18 problems

[Wolfleather]

Hello,
I have a Durkopp cl 18 at home, I found this manual a while ago which is great but I couldn't find it complete anywhere on the web. Does anyone have it complete or any contact to the author?

And now a problem that I'm just not able to solve. My top thread is making an awfully small eyelet, so the hook is unable to catch it. I've tried different threads and needles (I still have the original needles). But no matter what I do the loop is just too small. I have a nagging suspicion that I did something wrong in the renovation. 

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[Constabulary]

Hard to tell what what is wrong w/o having the machine in front of me. The D. 18 is a very special patcher I once restored one but never touched one again. Maybe this thread and the video I have linked may help

 

[Tigweldor]

Here is another vid on how to thread the Dürkopp.

 

Here is another vid that shows exactly how the arm is supposed to grab the thread and wind it around the shuttle - the uploader´s machine has probs doing just that constantly in a proper way - seems to be your exact problem.

I would just enter the vid´s title in Youtube and try to contact the uploader how he fixed his problem.

My Heinrich Koch Colibri has the same operating function - but it works just fine and I am hesitant to screw with a functioning unit by taking it apart.

What is very important is : the needle has to be exactly placed in the needle holder, so when a loop is formed it can be grabbed by the hooked arm.

If the needle is just turned a smidgen the wrong way - the arm can not grab the loop.

You also want the needle on the bigger side for your thread size - if it is to tight, it will have probs forming a loop.

Too much top tension (especially on the take-up spring) is also not helping the formation of a proper loop.

 

Edited April 28 by Tigweldor

[Wolfleather]

I have exactly the same problem as in the second video. I've been bothered by this monster for two months. Without the material it's not a problem and the loop picks up nicely, but when I put the material in the loop just gets too small. Aside from that it works beautifully, overall for being one of the first ones made (I have number 5347) so it's basically in perfect condition in terms of worn. I'm trying to hunt for information where I can and I'm still short on it. That's what I get for not buying a Singer 😄

[Tigweldor]

Have you tried moving the take-up spring one notch closer to the pivot point = less spring pressure on the arm due to less fulcrum/leverage ?

[Wolfleather]

Sorry for the late reply. I've tried everything, but I just don't know what the problem is. Knowing what I know, it's definitely just some little thing I can't figure out. 

[Tigweldor]

also show a pic of how you wound the bobbin thread within the shuttle.

I assume that you have the little short shuttle with one long hole on one side and a bunch of little holes on the other, like the one in the pics - not the newer type with a pressure spring.

There are also 2 types of shuttles - one with very small holes - the other with bigger holes.

You can NOT run heavy bobbin thread in the one with the small holes -- you have to use thin thread size and stick to it.

Or else use the other shuttle for thicker thread - and stick to thread size that you dialed it in for with the small adjustment screw at the "bow" as well as the number of holes that you wound it through.

In the pics, the thread is wound wrong.

First it goes through the long hole - passes over the top of the shuttle -  then through the little holes - from bow to stern

 

All said : this is a trial and error system until you get just the right tension. And then you better stick to exact same thread size and number of holes used - or repeat the whole process.

But your prob seems to be that the thread is not wound all the way around the shuttle by the little arm - that stems from a maladjustment in top thread tension so not enough thread is released to form a loop.

 

Edited May 8 by Tigweldor

[Tigweldor]

Here is a pic of the 2 different shuttles - see difference in mentioned hole diameter and number of holes analog to thread size used on the bobbin.

These shuttles do not move at all - they stay stationary as the arm wraps the top thread around the bow.

They are about as common as hens´teeth to find without having to buy the whole machine.

Edited May 8 by Tigweldor

[Tigweldor]

Talked to a bud today - who has way longer experience servicing old sewing machines than I do.

He said that on the old Dürkopp 18 you have to watch this unit :

To the immediate left side of the top thread tensioner there is another round thread guide.

The top of that thread guide goes up and down, powered by a cam from underneath, and releases just enough thread for proper loop forming before it pinches the thread again.

Now if timing of that "thread pincher" is out of sync - it will stop/bind free thread movement within the loop forming process and the arm that wants to wrap the thread around the shuttle bow will lose hold of the thread.

So you have to make sure that the plunger works with the up and down motion at proper timing.

Also make sure that needle to thread size fits just right - on leather it is better to go on the large side of needle sizing, so thread can form a loop and is not being pinched into the needle groove by to tight of a fit of the hole in the leather - thus not being able to form a loop because the needle pulls the thread up on the up stroke.

So if you do not have different size needles at hand - just try thinner top thread for now.

If all works out then - you have found the prob and can order bigger size needles for the thicker thread

Hope that helps you out

Greetings

Hans

Edited Friday at 09:50 PM by Tigweldor

[Wolfleather]

Thanks for the answers. There's some black magic in that machine. If I hold the end of the top thread, the machine works. So I think there's really a problem somewhere with the top thread tension setting.