Bi-Metal M42 Hole Saw take the form of a short open cylinder with saw-teeth on the open edge, used for making relatively large holes in thin metal materials.
Adjustable Arbor For Hole Saw
3/8" hex shank,with 1/20" -20UNF thread.
fitting hole saw diameter 9/16" to 1-3/16" (14mm to 30mm)