Ok, you can lock the chainstitch so that it doesn't unravel from the end of the stitching, but if the stitch breaks somewhere, it will unzip easily. This is one of the reasons why they didn't become as popular as the lock stitch machines. Do you have a manual for your machine? There are instructions for locking the stitching in the manual. I use my c-stitcher for basting, temporary alterations and for embroidery work, never for finish stitching.

Annie

I forgot to mention that I can give you the names of some sellers of good reproductions of original manuals.

Annie

I know this is a bit late... lol I use my Willcox & Gibbs machine all the time.
What I do to lock the chain at the end a seam is to simply run it a few stitches further off the fabric. Then lift the presser foot, gently pull the piece so the thread is out a few inches, clip it with scissors, then pull the end of the thread so that it tightens into sort of a 'knot'. When trimming the tail off, DON'T clip too closely to the knot... allow approximately 1/4" tail to remain.

This isn't a 100% guarantee, but I have things that I made from the 50's - 60's that still are holding strong. The beauty of the W & G machine is the delicate stitching. The stitch length ranges from the largest at 12 stitches per inch to a verrry tiny 30 stitches per inch. The home machine was used for homemakers to sew the delicate fabrics like silk, organza, voile etc.

Anyway, sorry I'm late, but interesting info. I come from a long-line of Willcox % Gibbs fans. I learned to sew on my grandmother's machine in the early 50's and couldn't sew without one... :-)