V.P., Great old Robeson with beautiful handles.
waynorth and Campbellclanman, wonderful Robeson examples with all the right bells and whistles.
Lostball, I did quite a bit of research into the Alfred Field company some time back for an article. While Alfred Field never produced any of their own knives they did carry quite a line up of their own brands and were the United States reps for Joseph Rodgers from 1891 to WWII. Alfred Field hosted at least nine different cutlery company brands which included, Alfred Field & Co., Parker & Field, Progress, Criterion, Branford Cut. Co., Continental Cut. Co., Waltham Cut. Co., Alex Fraser & Co., and Jones & Co. While Alfred Field did contract out to various German cutlery companies for many of their house brands, they also contacted out to American companies. It appears that they used Schrade Cut. Co. mostly and I believe your single blade ebony jack was made by Schrade. Enclosed is a Schrade catalog cut from 1928 showing what I believe is your model. Note that the the cut shows a spear blade but the description also offers the knife with a clip blade and ebony handles.
View attachment 989278