General Tools 55 Heavy Duty Circle Cutter Thread Type - End 1:

Thread Type - End 1: NPT

Head Material: Steel

and is safe for use on glass

Designed to clean hard to reach windows with ease

General Tools 55 Heavy Duty Circle Cutter Thread Type - End 1:The General Tools Heavy Duty Circle Cutter can produce precise circles in sheet metal, brass, copper, soft steel, aluminum, plastic, wood and composition materials. Durable body of heat treated tool steel. Adjustable to various diameters by included hex wrench. Only safe to use with drill press running at less than 500 rpm. Included blade (#55 Blade) and 1 4 in. pilot drill bit (#5 6 55 Drill) are replaceable. Diameter range: 1 3 4 to 7 7 8 in. Shank