Beginner ques: My backstitch doesn't seem to lock the stitches
My 7 year old son and I are learning to sew together (he just loves it--I see a future tailor in the family).
We are using my mom's old 1965 Singer Touch and Sew 603. It was seldom used by her, and was given to us with all the original parts. It spent a little time in the shop b/c the bobbin wasn't working properly. But it works pretty well now for straight stitching (the zig zag isn't working right, but oh well).
So here's the problem: backstitching doesn't seem to lock the stitches at all. When I come to the end, if I only backstitch once and then cut the thread, pulling on the end to trim it will pull the stitches out of the fabric.
So I have been backstitching repeatedly. I come to the end. Reverse about 5-6 stitches. Forward again. Reverse again. Forward again. Reverse again. Cut. If I pull on the thread, it will still start to come loose, but I figure that with all that overlapping stitching, it would take a while for it to all come loose.
Any ideas about what is going wrong here?