This Encyclopedia entry is a must-know term. Learn more in our Denim vocabulary.
The roping effect is a type of abrasion on the hems of jeans where it looks like its twisting around itself. It becomes visable after wear and especially after wash.
It is the sought-after result of what is technically an error in vintage chain stitch sewing machines.
The best roping effect is seen on hems stitched with Union Special 43200G Edge Locker. But what exactly is it that creates the roping?
Interestingly, it is in fact not the Union Special 43200G itself that causes the roping effect.
The main reason for the abrasion is what is called the feed differential; caused by a folder that affects the way that the material is metered through the machine.
43200Gs are plain feed machines, which means they have a static presser foot and one set of feed dogs on the bottom.
Many modern machines have walking feet, needle feed, or differential feed dogs to ensure that the top layers and bottom layers being sewn move through the machine at the same rate.
Read more about chain stitching here.