Bi-metal carpentry hole saw with variable tooth pitch, teeth in HSS, welded onto cylindrical base body, including exchangeable hexagonal shank (SW 12), please order guide arbor with drill head separately, for sawing holes in larger diameters in a single operation, e.g. for feed-throughs of exhaust air supply pipes and drainage pipes in roof constructions, this hole saw cuts all insulating materials (glass wool, rock wool, polystyrene, etc.) as well as wood, chipboard and plasterboard.Due to its design, it is not possible to cut solid wood with a thickness of more than 30 mm or all types of metal and stone; the carpentry hole saw can be used freehand with a powerful hand drill without tools