ADLER 205 is dropping stitches, fraying etc.

[HazelB]

I'm having some trouble with my Durkopp Adler to 205 - 370 not wanting to back stitch.  The hook is not catching the thread most frequently when in reverse.

It is also randomly dropping stitches when sewing forward.

But the really puzzling part is the top thread sometimes frays and unravels. 

 For details: I'm using a 180 needle  and 200 shim. Thread tension is good, top and bottom. Needle is centered properly and is not making contact with shuttle. Serviced by a pro 2 weeks ago and all checked out fine.  

Help! 

[jimi]

2 hours ago, HazelB said:

Serviced by a pro 2 weeks ago and all checked out fine. 

If all was working before it was serviced then i would take it back.

[Uwe]

What size thread is that? It looks quite hefty in the photo. Your needle may simply be too small for that thread. Is that your normal needle/thread combination?

I would also check for burrs that can easily fray thread. Every braking needle may create a burr in the foot, feed dog, etc. I check for burrs by running thread through holes (foot, feed dog, separately) and pulling it back and forth with my hand, changing angles in a full circle. If the thread frays, you have a sharp edge somewhere that needs to be smoothed or polished. I use abrasive cord to “file” inside holes smooth (after removing the part from the machine)  

I’d also double check hook timing to make sure it hasn’t slipped. Do a few very slow, hand-turned stitches on a very small piece of leather. Flip open the hook cover and just observe how the hook picks up the thread and makes a knot. Try reverse, too. You may need to remove the needle guide and spacer , and crane your neck to see what’s going on.

It would not be the first machine that came back from service with a screw that’s not tightened quite enough and comes loose soon afterward. Something may have slipped, causing timing problems.

You may need to remove feet and throat plate to see how the hook and needle dance together. 

Also look at the needle height. If the needle is too low, the hook may still pass the needle in the scarf area, but the needle guard (really just a surface on the shuttle driver) may deflect or collapse the thread loop that the hook is trying to catch.

You may need to temporarily remove the needle guide and spacer plate to observe this as it is shown in the videos below. 

I made some videos a while back that show the stitch formation on that machine. They give you some idea what to look for and do a sanity check.

The needle height in the first video is actually too low (but it still made a stitch) Note how the eye of the needle goes below the edge of the needle guard (the line where the vertical part of the needle guard transitions to the angled part.) The vertical wall of needle guard “covers” the eye of the needle, which is incorrect.

In the second video the needle height is correct and the eye of the needle stay just above the edge of the needle guard the entire time.  

 

Edited October 1, 2020 by Uwe

[chrisash]

I think the problem is in threading the machine, that twisted thread is not right in the photo

Try re-threading 

Try a new cone of thread

[shoepatcher]

Check the timing BOTH in forward and reverse.  That hook must come as close to the needle as possible without touching it.   Timing could be fine in forward but not in reverse.  Allen Burkholder at Weavers is probably the finest technician on that machine in the WORLD.    I say that because he has worked on this particular model of machine for over 25 years.  He knows them backwards and forwards.  He has taught me a lot about the machine.    Steve at Cobra and Bob at Toledo are also very very good,   All of them will tell you the hook must be ever so close to the hook without touching it. 

I would try another spool of thread as well. Check the thread path for burrs as well as the hook.  These machines do get out of time both hooks and needle bars. 

One way to check the timing is to sew forward and then go in reverse 12 stitches.  If it misses at all in  those 12 stitches in reverse, timing is off.

glenn

Edited October 2, 2020 by shoepatcher

[HazelB]

Thanks all! I will try all of your suggestions, its helpful to know what to look for and test. Much appreciation.