Hi Bruce,
Excellent display, I enjoyed your video very much. Many years ago I restored a Wilcox and Gibbs sewing machine for a museum, if memory serves it was a lock stich machine used by milliners.
Take care Tony.
Hi Tony , I had to look up Milliners (women's hats) in my research they were made for general sewing, the one I have is the industrial version & Yes they are a "chain stich" machine, meaning they loop the stich upon itself underneath with a special revolving hook below the fabric platform....no thread bobbin is used on these machines.