Singer 401/403/404 Tension Adjustment

Today I dug out a Singer 403 that I haven't used in a long time (maybe never).

I'm not sure I ever serviced this machine when I got it because there's some tape residue on the vertical pillar that I would've cleaned off if I had ever cleaned and oiled The machine.

As I was sewing on my project, I noticed suddenly I was getting loops on the underside of the fabric. It had me stumped for a minute until I saw that my upper tension dial was at zero. The tension knob was so loose that just the slightest bump moved it from its desired setting.

As I was getting ready to correct that situation, it occurred to me that maybe some others would like to know how that's done so I got the camera out and took some pictures of the process.

  There are many styles of tension assemblies, this is the one used on the Singer 400 series. Once you get the external knob off, you find that all upper tension assemblies are very similar inside.

Here is a clip from the service manual telling how to disassemble the 401/403 tension assembly.  To merely tighten the knob, you only need to perform these two steps.

After the thumb nut L5 is removed and the split stud is exposed, insert the blade of a flat screwdriver in between the two halves of the split stud Q2 and spread the two halves slightly apart. That will tighten up the thumb nut L5 when you screw it back on.

If you get the stud halves spread too far apart and the thumb nut L5 will not go back on, squeeze the stud halves back together a bit with pliers and try again until you get it where you want it.

 I had previously noticed that the +|- indicator was skewed off to one side so while I had the tension assembly open, I thought I would fix that also.

There is a set screw inside the nose door that holds the entire upper tension assembly in the machine. Loosen that set screw and you can turn the assembly to any position you desire. When you have it where you want it, tighten that setscrew and you're ready to reassemble.

Assembly is the reverse of disassembly.

After the tension assembly is reassembled, you want to adjust the tension so that you have a good balanced stitch with no regard to the numbered dial.

Once you have a good stitch, push in the numbered disc D5 and rotate so that the number 4 appears at the top of the dial at the +|- indicator. Release the numbered disc and make sure the pin C5 is seated in one of the holes in D5 and you're done.

Ed

The No-Name Sewing Machine

A lady dropped off a sewing machine last week. She said it didn't sew, she had tried to sell it and got no takers, so I could have it for parts. This was my first view - a plain, white generic plastic carrying case.  I wonder what kind of machine is in there...

Well, that's unusual, a sewing machine with no obvious badge or manufacturer's name.

Maybe it's on the back...Nope, nothing

I'll tip it over, there's bound to be a manufacturer's logo or JA number...Nope, nothing there, either.

I'm sure it will be on the serial number plaque - Nope, nothing there but a serial number.

Here's the only identification information - a tiny sticker saying, "Made in Taiwan".

Tipping it over to look at the serial number, I noticed that the bobbin case was not installed properly.  That could be why it doesn't sew.

Removing the bobbin case and shuttle, I spied red thread behind the shuttle. Maybe that's why it doesn't sew.

There was a serious burr on the point of the hook, so bad that fine abrasive wouldn't take it off.  I had to clean off the burr with a file, then polish with the fine abrasive.

After oiling, I threaded it up to test sew. First thing I noticed was that the tension did not release when the presser foot was raised. The paddle that presses the tension release pin on the back side of the tension assembly appears to be bent.

I tried to bend it back without removing the whole light/needlebar/presser bar/swing assembly but couldn't get it where it needed to be.  If I couldn't make the paddle reach the pin, maybe I could make the pin reach the paddle.  I disassembled the tension assembly and removed the pin from the front and cut a same-diameter finish nail to about 2-3mm longer than the original pin, that has worked for me in the past.

That still wasn't long enough, I guess I'll have to continue turning tension to '0' to thread the needle until I figure something else out or find a longer finish nail or bite the bullet and remove all the mechanicals to get at that paddle.

On the first test run, it sewed pretty well - a bit noisy, but changing the orange, toothed tractor belt for a smoother version quieted it down significantly.

 I learned that it is a left-needle zig zag machine, at '0' stitch width, the needle sits at the far left end of the hole in the throat plate; as stitch width is increased, the needle swings farther and farther to the right. That configuration makes it tougher for a quilter to judge a quarter-inch seam but having the fabric supported on three sides in straight stitching mode reduces the possibility of the fabric getting sucked down under the needle plate.

Now, I need to use it on a project to see how it performs in the long run.

Ed
Ed's Vintage Sewing Machine Shop

Necchi Supernova Tension Release Adjustment

Frank was also having a problem with the upper tension release.  He said the disc opening lever “N” in the figure below that is supposed to press the disc opening rod in the back of the tension assembly was not close enough to the end of the release rod to do its job and release the upper tension.  If his machine had the tension assembly removed for any reason or the tension knob had been bumped, the position of the tension mechanism could be incorrect.

Hopefully, this procedure will correct that problem.

It is very important to check whether the position of the tension mechanism is correct.

-          Set the presser bar lever in its intermediate (embroidery) position.

-          Check that the disc opening rod “B” in the below figure is as close as possible to the disc opening lever “N” without actually touching.

-          Ensure that the thread take-up spring can move freely without rubbing against the machine arm.  Distance “a” in the below figure should be about 1/16” (1.5mm)

If an adjustment is needed, loosen screw 048050 GEB and move the entire tension mechanism along its axis (do not rotate it) then tighten screw 048050 GEB firmly.

Ed

Ed's Vintage Sewing Machine Shop

The 66 is Finally Finished!

  I spent most of the day putting the finishing touches on this machine.  All I had left was the tension assembly and the bobbin winder and it would be ready for testing.  The bobbin winder went without a hitch. I love those old bobbin winders with the guide finger that precisely positions the thread winding on the bobbin so it comes out perfect. I'm sure that economics was the reason they were replaced with the lower quality contraptions on later machines because there are  many more parts and moving parts on the older winders.

  On to the tension assembly - when I separated the tension discs, there was a piece of thread lodged between them, possibly the cause of some previous tension problems.

  I cleaned and reassembled the tension assembly and installed it. It regulated tension all right, but did not release when the presser foot was raised. Do you see anything wrong with this tension assembly component?

  Neither did I the first time around but I knew there should be some piece with a bar passing between the sides of the split stud. The pin in the tension assembly needs something to push against to release the spring pressure from the outer disc.  The part should look like the one on the right here

  I threaded it and found that the upper thread would not pull up the bobbin thread.  The hook was a bit out of time from being disassembled for cleaning. After re-timing the hook, the machine seemed to be binding. I had adjusted the feed dog centering and tightened the screw back down too tight. with the machine running smoothly and sewing like it shoud, I noticed that one of the motor wires had a gap in its insulation so I had to replace the motor again and find a belt to fit. It seemed like it was one thing after another and took all day. We are in the middle of an ice storm, so I wasn't going anywhere anyway, but I could have found other tings to do with the time.

Here is the finished product. Not the best looking machine I have ever put out the door but considering the condition it arrived in, not too bad.