Knightsbridge 80mm Bi-Metal Holesaw - 4/6 TPI Variable Teeth

The Knightsbridge 80mm bi-metal holesaw features a bi-metal construction with 4/6 TPI (teeth per inch) variable tooth geometry designed for cutting steel, stainless steel, die-cast metals, hardwood floors, plywood and plastics. The variable pitch reduces vibration and extends blade life when cutting through dense or layered materials, while the bi-metal edge provides wear resistance beyond what carbon steel or high-speed steel alone can deliver.

Designed for electricians, joiners and general contractors installing electrical accessories, downlights and cable entry points, the 80mm diameter suits standard back boxes and mid-sized fittings requiring an 80mm cut-out. The 38mm cutting depth handles typical installation depths in studwork, plasterboard, timber joists and sheet metal enclosures without needing multiple passes. The holesaw fits the Knightsbridge HSARBORL arbor (sold separately), which provides the drive shaft and pilot drill for centring the cut.

The bright yellow finish coating improves visibility when the saw is set down on a workbench or in a tool bag, and provides corrosion resistance during storage between jobs. The bi-metal edge combines a high-speed steel cutting surface welded onto a flexible alloy steel body, giving the saw resistance to tooth breakage when it catches on hidden fixings or grain knots. The sawtooth geometry alternates between 4 TPI and 6 TPI across the cutting edge, which clears swarf more efficiently than a uniform pitch and reduces binding in deeper cuts.

Product Specification Sheet

What arbor does this holesaw require?

The 80mm holesaw fits the Knightsbridge HSARBORL arbor, sold separately. The arbor provides the hex drive shaft, pilot drill bit and threaded collar that secures the holesaw during operation.

What materials can it cut?

The bi-metal construction handles steel, stainless steel, die-cast metals, hardwood, plywood and plastics. It is not suitable for masonry, brick or concrete — those require diamond-grit or tungsten carbide hole cutters.

What does 4/6 TPI variable teeth mean?

The tooth pitch varies between 4 teeth per inch and 6 teeth per inch around the cutting edge. Variable pitch reduces vibration, clears swarf more efficiently and extends blade life compared to uniform-pitch holesaws, particularly when cutting layered or dense materials.

Can the saw be resharpened?

Bi-metal holesaws are generally not resharpened in the field. Once the teeth dull or chip, replacement is more cost-effective than attempting to re-grind the variable-pitch edge geometry.