Why won't my Elna SU zigzag or engage the disc cam stitches.

SOURCE: Elna SU missing stiches and breaking thread

it sounds like the needle hook timing is out. You need to get the needle in the lowest position and measure the gap from the needle to the hook point on the bobbin shuttle. It should be 1/4". You will need to remove the foot and foot plate to be able to see. I use a 1/4" drill bit as a gauge. If you need to adjust it, you will need to remove the free arm cover to the right of the foot and loosen the 2 allen head screws that hold the drive gear. Adjust the gap, tighten the screws and retry. Usually if the needle catches the thread to early, it will make a bad stitch and the upper thread will break. If it catches to late, it will make thread loops and the machine will skip stitches. Good luck, these are a good machine and worth fixing. Phil

SOURCE: Machine sews zigzag although stitch is set at 0 for straight

It must be a design flaw- things don't always last like they are supposed to. I would personally check the physical reason it is not responding... knowing what it would take to make it stop moving- or whatis causing it to. *perhaps the switch isn't working to stop it- or the mechanism that controls it is worn down. If it was new- I'd return it- but there are only a few options at this point.

SOURCE: have a 1970's elna su supermatic but cams don't work

There are two types of discs - single and double.
For the thinner single discs do as follows:
1.Turn stitch width knob to "0"
2. Turn stitch length knob to "0"
3. Insert the single disc
4. Turn the top selector to "A"
5. Make sure the needle selector is in the centered position.
6. You may now choose any stitch length or width you wish. I usually try "3" for the width and 1/2 for the length to start.

For the thicker double discs do as follows:

1.Turn stitch width knob to "0"
2. Turn stitch length knob to "0"
3. Insert the double disc
4. Turn the top selector to "A"
5. Make sure the needle selector is in the centered position.
6. You may now choose any stitch width.
7. The stitch length must be put on "A" - this is the difference between the single and double discs!
I hope this helps!

SOURCE: Elna machanical sewing machine

50 year old elnas made stitches by cams. look to see if the machine has a cam in it. you can see this by opening lid on top of machine. cams are black with red or white showing the pattern of the cam. could also have broken cam stack gear. That would require technician with elna experience

SOURCE: why straight stitch will not work but zigzag and herringbone stitches work on my machine.

it sounds like the machine needs to be checked at a sewing
machine shop to see what's wrong with the cam's or gear
that makes the stitches