These high-speed variable pitch bi-metal hole saws are ideal for cutting perfectly round and accurate holes in metals plastics and wood up to a depth of 35mm 138” They offer a hardened M3 steel cutting edge that is welded to a tough alloy steel body making them very durable and hardwearing The construction reduces the risk of shattering The holesaws have four side slots for removal of slug as well as a female threaded spindle for fixing to a 95mm arbor It can be easily attached to power drills for a fast clean heavy-duty cutting action in stubborn materials When metal cutting it is advisable to use a lubricant to prolong the service life of the hole saw such as Stock No 76109 - Metal Cutting Lubricant 400ml To complete the holesaw assembly a holesaw arbor is required