Old 06-02-2012, 02:00 PM
  #1  
J Miller
Super Member
 
Join Date: Feb 2012
Posts: 8,091
Default Need Help, I'm stumped. Tension Problems - BIG time.

Well, it seems that something really went wrong with the Kenmore 120-491 I wrote about here:
http://www.quiltingboard.com/vintage...e-t189987.html

Some time after that post I had done some sewing and it sewed really good, not perfect, the tension at the longest stitch length was a little off, but nothing that made me worry.
Then I showed my wife how the feed dog dropper worked and since then it will not sew right.
The tension has gone on the fritz.

There was a place with icons on the top so one could put pics in order along with the text, I can't find it now. So I'm going to put the pics in as attachments.
Pic 1 is the top thread. You can see that at setting 7 it's OK, then as the settings were reduced the tension went limp.
Pic 2 is the bottom thread. Pretty much self explanatory. At the top tension setting of 4 it will not sew more than a few inches before the machine just jams up. Before it was sewing decently at that setting.
Pic 3 is the thread jams that occur on and around the bobbin at settings 4 and under.
Pic 4 is the top tension. I have not removed it or altered it in any way.
Pic 5 is a shot of the bobbin assembly and it's gate.
Pic 6 is the rotary hook and the inner bobbin carrier with it's two piece hook. The bobbin carrier cannot be removed from the rotary hook, the outer part spins around the inner carrier on the nylon rim you can see at the inner hook.

Now, here is what I have done:

>Read the owners manual and made positive sure everything is threaded and adjusted properly.
>Cleaned the machine thoroughly.
>Lubed it.
>From the time it sewed OK, till the when it went on the fritz the only things I did was show my wife how to disengage the feed dogs for FMQ. (and that was done as the instructions indicated) and replace the old bent needle.
The design of the feed dog drop system precludes anything getting out of alignment.
>Checked all the hooks, there are two on two separate parts, for burrs. Didn't find any.
>Checked the bobbin carrier and case at the top where the thread has bound up for burrs, did feel something on the case and polished it off. Made no difference.
>Adjusted the upper then the lower, then the upper alone, and then the lower alone tension to see if that is the problem. To make it sew I have to run the upper tension to 8. At this point you cannot pull the thread through the needle without it breaking. It is that tight.
>Watched carefully as I turned the machine through stitching cycles by hand. I can see where it's jamming up, see pic 3, but I cannot figure out why. Once past 4 there is enough upper tension to pull the thread around but not to stitch properly.
>Run the machine with out thread and needle to see what happens. At low speed the bobbin case just sits there. At high speed it vibrates in and out like crazy. But the tension problem is not influenced by machine speed. It happens at all speeds.
>I've read everything I can find about tension problems but nothing I've read covers this kind of malfunction.


This machine is not responding to the things that would normally fix a tension problem. It's my thoughts (my wife's too) that the problem is in the bobbin area. Instead of sliding around the bobbin carrier the thread is catching on it somewhere and it's taking a lot of upper tension just to pull the thread through.
You can see some of this area in Pic 6.

I need some help with this one. More to read maybe, I can't seem to find anything that helps with this problem.

TIA

Joe
Attached Thumbnails top-thread.jpg   bottom-thread.jpg   thread-jam.jpg   top-tension.jpg   bobbin-assembly.jpg  

bobbin-hook-carrier.jpg  
J Miller is offline