Consew 206RB-4 Shredding Thread

[garypl]

I have been going round and round trying to get my Consew 206RB-4 to sew harder temper leather up to @1/4” thick.  It sews light temper upholstery leather fine (most of the time - occasionally skips a stitch).  I am using a23 needle with 138 bonded nylon top and bottom.

As shown in the video, thread starts missing stitches almost immediately with a piece of 12 oz veg tan.  

I have been going through all of the adjustments and I guess I am not hitting the right combination to get it stitching reliably.  I adjusted the check spring to keep thread taut until needle enters the leather.  I am hoping that someone here can look at the symptom and get me started in the right direction!

Gary

[Wizcrafts]

You might have a better clue about why this is happening if you can find a way to watch the hook as it intersects the needle. One way would be to tilt the head back to the peg and hand wheel the machine. Leave the stack of leather in it. Pre-punch the holes if you must to get the threaded needle to go through the stack. Aim a work light at the hook and watch what happens as you rotate the wheel. The loop may be too small, or dissolved already, or the needle may be deflecting too far to the left for the hook to pick off the loop.

[cdthayer]

2 hours ago, garypl said:

I have been going round and round......

I’m in the same boat with you, and share your frustration.  My Adler 205-370 was sewing just fine in May, both on leather and woven samples, then, I didn’t use it until mid-July.  Now, it shreds the thread on the third stitch (bonded Tex350 poly thread top and bottom, 7x3-26 round-point needle), and misses the fourth and beyond stitches.  The needle even sews through the upper thread at times.

Nobody has been around it, and I haven’t changed a thing except to unthread the upper thread while I wasn’t using it.  I haven’t touched the bobbin thread.  I threaded it back up on top, and the problem started.  I threaded it with a different spool of thread.  Same thing.  I can't figure out WHAT I'm doing different!  AAAAARGGGG!!!!!

CD in Oklahoma

 

[RockyAussie]

Stall video at 12 seconds in. There is no way that scarf of the needle should be facing forward. Spin the needle scarf to face the bobbin hook.

[garypl]

8 hours ago, Wizcrafts said:

You might have a better clue about why this is happening if you can find a way to watch the hook as it intersects the needle. One way would be to tilt the head back to the peg and hand wheel the machine. Leave the stack of leather in it. Pre-punch the holes if you must to get the threaded needle to go through the stack. Aim a work light at the hook and watch what happens as you rotate the wheel. The loop may be too small, or dissolved already, or the needle may be deflecting too far to the left for the hook to pick off the loop.

Wiz, I don’t see how I can watch the hook with leather in the machine.  Only view is from the top.  Here is a video of the needle-hook timing.  I think it looks ok.

 

Here is another look as I try to stitch a piece of 8 oz veg tan.  It starts intermittently skipping stitches when I speed it up about 2/3rds of the way into the video

 

1 hour ago, RockyAussie said:

Stall video at 12 seconds in. There is no way that scarf of the needle should be facing forward. Spin the needle scarf to face the bobbin hook.

Brian, I think it was just the lighting that made it look like the scarf was to the front.  It is definitely pointed toward the hook.  I tried fiddling with scarf position - rotating needle  slightly in each direction, but no improvement.

Any suggestions after looking at these videos?

Thanks for the help!

Gary

 

[mikesc]

Can you not sew just right along an edge ( about 5mm in, just enough so the leather doesn't try to go down the hole with the needle ) edge to the right side facing the "harp", and take the sliding bobbin case cover off to have a look what is happening as the needle goes through and the stitch is made, or in this case not made occasionally.

Edited August 1, 2019 by mikesc

[garypl]

3 minutes ago, mikesc said:

Can you not sew just right along an edge ( about 5mm in ) edge to the right side facing the "harp", and take the sliding bobbin case cover off to have a look what is happening as the needle goes through and the stitch is made, or in this case not made occasionally.

I could not see the hook unless I removed the RH cover plate.  Without the plate in place I don’t see how I could sew a piece of leather as there would be nothing supporting the leather except the feed dog.  But perhaps I am overthinking this - I will try removing the cover plate again and see if there is any way I can sew and see the hook at the same time.

 

[mikesc]

Try putting a strip of card 20 mm wide ( piece of cereal box ) under say a 20mm strip of the the leather to support it , and sew just 5mm in from the edge with the right side cover off..You should be able to see what is going on without the leather going down the needle hole...let the edge of the leather/ card sandwich run along the RH edge of the plate that the feed dogs come up through..the card will support it..

Another moment to be thinking "and if I made a right side cover out of clear perspex for just such times" :)

Remember those spark ( ignition ) plugs with a clear body that you used to be able to get back in the 60s, so you could see what colour spark you were getting on each cylinder of an engine by swapping them out for the normal plugs one at a time ?.. "trouble shooting bobbin case covers in clear perspex"..I must patent it ;)..except I think loads of domestic sewing machine manufacturers got there already..prior art..although USPO would probably award a patent to me anyway..they seem to "award any patent first , take the registration money, and then let the lawyers fight it out"..

Edited August 1, 2019 by mikesc

[RockyAussie]

The hook timing looks alright so the next things I would normally check is if there is a small burr on the needle end or if it is bent a little.  Sometimes changing the needle will confirm this. This is not uncommon. After that is there anything along the top thread path going back to the thread cone that could be causing any elasticity of the thread? In particular in the area of the movement of the thread return spring. 

[garypl]

1 hour ago, mikesc said:

Try putting a strip of card 20 mm wide ( piece of cereal box ) under say a 20mm strip of the the leather to support it , and sew just 5mm in from the edge with the right side cover off..You should be able to see what is going on without the leather going down the needle hole...let the edge of the leather/ card sandwich run along the RH edge of the plate that the feed dogs come up through..the card will support it..

 

Mike, I took your advice and removed the cover plate from the hook area and sewed the same piece of 8 oz leather - see video here:

It sewed perfectly!  I ran two lines of stitches without any problems - see picture showing two rows of stitches on top edge.

So, the only thing I did was remove the cover plate.  Upon further examination of the cover plate I saw that the LH edge was bent - see pictures:

I never noticed this before, but I do remember that the feed dog seemed very close to the left side of the cover plate slot - feed dog was probably rubbing against it.  

So I think my next step is to order a new cover plate and ensure there is clearance between it and the feed dog.  I never would have thought this would be the problem.  Just goes to show you that we have to take note of every small detail when troubleshooting a problem.

My thanks to everyone for pointing me in the right direction, especially Mike, who suggested running without the cover plate in place!  I will update this post after I replace the cover plate and verify it still sews!

Gary