Millsaw files have parallel surfaces with the edges tapering toward the point. Surfaces and edges are single cut - commonly referred to as mill bastard.
This type of file is suitable both as an engineering file and a sharpening file. It is useful for filing where a smooth finish is important. Also good for polishing and deburring work in lathes. This file is also widely applicable for sharpening tools and implements such as spades, shovels, hoes, scrapers, etc.