My singer 1120 will sew straight stitch but not zigzag

SOURCE: How do I change the stiches?

You can do all of these stitches by using different combinations of your stitch selector, stitch width and stitch feed knobs, for instance, on the panel I can see on your machine:

http://www.jo-ann.com/joann/product/images/52659.jsp?CATID=cat3122&PRODID=prd11333

Stitches 1, 2 & 3 are straight stitches, centered, left and right. Really basic stuff, not different stitches at all. 4,5,6,7 & 8 are zig-zag stitches of different widths. 9 is the widest zig-zag (no. 8) on a finer stitch length, etc...

I think you should try and get an instruction manual for your machine. After a lengthy search of my usual manual sources, I've determined that that this may not be so easy. I think you should contact White on their 800 number and let them try and help you... 1-800-331-3164.

If you found this helpful, please vote generously as I receive nothing other than acknowledgement for my time.

SOURCE: Singer 5050

I was hoping you would have got another answer, I have a mechanical sewing machine ( Singer 5040) with the exact same problem. However, if i use the programed stitches I can sew a zigzag. If i do it manually and set the zigzag width to any width ( even the widest) I get only the same straight stitch, and no mater what length I select it is the same too, very close to gether about 1 1/2 inch stitch.
I took my entire maching apart to expose inside both top side and underneath, nothing apeared loose or broke and i oiled it up. I bought a new bobbin holder and still the same effect. So it has to be something serious is my conclusion...sounds like a trip to Sears to me...LOL

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: Singer Touch Tronic 2001 Sewing Machine Stuck on Sewing Straight Stitch Only

I had a similar problem a couple of years ago. I finally figured out that I had the straight stitch needle plate (the one with the single hole), rather than the zig zag needle plate (the one with the curved hole). When I changed plates, it worked fine.

SOURCE: singer machine needle won't do width in zigzag

It sounds like it needs lubrication on the needle bar frame and linkage.