This awl is described in the Encyclopaedia of Diderot and D'Alembert, Paris, c 1760, as an English style awl. As with all shoemaker's tools there can be a great variety in size - they can vary from 60mm - 100 mm in length and be of different thicknesses and curves. It is important that the hole made by the awl should be of a smaller size than the thickness of the thread which will pass through it, to ensure a tight fit.
Shoemaker's awl are interchangeable with saddler's awls .
Ref: R. A Salaman, Dictionary of Leather-working Tools c1700- 1950. Allen & Unwin, 1989.