Why were early sewing machine attempts that focused on single-thread chain stitching found to be inadequate?

Answer

They were prone to unraveling if one link broke

Early inventors struggled to replicate the durability of a hand stitch, often experimenting with single-thread chain stitching techniques because they were fast to automate. However, this method suffered from a major structural defect: it relied on a continuous chain where each loop was dependent on the next. If any single point in that chain failed or broke, the entire seam structure would immediately begin to unravel, rendering the stitch unreliable for clothing that needed to withstand wear and stress. The invention of the two-thread lockstitch was necessary to overcome this inherent instability.

Why were early sewing machine attempts that focused on single-thread chain stitching found to be inadequate?
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