85mm Bi-Metal Holesaw - Knightsbridge

The Knightsbridge 85mm bi-metal holesaw combines a high-speed steel cutting edge with a spring steel body, giving it the durability to cut through ferrous metals, stainless steel, die-cast alloys, hardwood floors, plywood and rigid plastics. The 4/6 TPI variable tooth pitch alternates between coarser and finer teeth around the cutting edge, reducing vibration and heat build-up during drilling compared to fixed-pitch teeth.

Designed for electricians fitting downlights, HVAC installers running ducting, carpenters cutting clearance holes in joists, and maintenance engineers working on metal enclosures, the 85mm diameter suits products requiring an 85mm cut-out. The 38mm cutting depth handles standard UK stud walls (63mm timber with plasterboard both sides), 32mm worktops, and sheet steel up to 3mm thick in a single pass. The saw fits Knightsbridge HSARBORL arbors and most standard arbor shafts with a hex or SDS drive.

The bi-metal construction uses electron beam welding to bond the high-speed steel teeth to the spring steel cup, creating a joint that withstands the shock loads and lateral forces that crack all-HSS holesaws when cutting metal. The yellow finish provides corrosion resistance and makes the saw visible in a tool bag. After cutting ferrous metals, clear swarf from the teeth with a wire brush to maintain cutting performance on subsequent holes.

Product Specification Sheet

What arbor does this holesaw require?

The 85mm holesaw fits the Knightsbridge HSARBORL arbor and most standard arbor shafts with hex or SDS drive. The arbor is sold separately and includes a pilot drill bit that centres the holesaw before the teeth engage.

What materials can it cut?

The bi-metal construction cuts steel, stainless steel, die-cast metals, hardwood floors, plywood and rigid plastics. For softer materials like plasterboard or softwood alone, a cheaper carbon steel holesaw is usually sufficient, but the bi-metal version handles mixed-material drilling (e.g. plasterboard over steel stud) in one operation.

How deep can it cut in a single pass?

The 38mm cutting depth handles standard UK stud walls, 32mm worktops, and sheet steel up to 3mm thick. For thicker materials, drill from both sides to meet in the middle, using the pilot hole from the first side to align the second cut.

How is the holesaw maintained after use?

After cutting ferrous metals, clear swarf and metal filings from the teeth using a wire brush. For plastics or wood, compressed air or a stiff-bristled brush is usually sufficient. Store the holesaw in a dry environment to prevent rust on the cutting edge.