🔧 KHCRAFT 13 Piece Bi Metal General Carrying Kit Review

Professional high speed steel M42 (not M3) with cobalt 8% cutting teeth hardened to control the efficient and durable and reliable use on workpieces like sheet metal, Aluminium, wood, plastic, plasterboard, etc. HSS M42 teeth is particularly good for high strength metal such as stainless steel (HSS M3 ones are good for middle strength metal but not high strength one) because HSS M42 contains cobalt 8%, which raises the hardness of the teeth. HSS M42 is about 20% more durable than HSS M3. 9-piece hole saws: 3/4"(19mm), 7/8"(22mm), 1-1/8"(29mm), 1-3/8"(35mm), 1-1/2"(38mm), 1-3/4"(44mm), 2"(51mm), 2-1/4"(57mm), 2-1/2"(64mm); 4-piece accessories: arbor 9/16"-1-3/16" with shank 3/8"; arbor 1-1/4"-6" with shank 7/16"; arbor adapter 1/2"-20UNF to 5/8"-18UNF; arbor center drill with shank 1/4". Center drills in this kit are all made of real HSS M2 and fully ground, while a lot of bi-metal hole saw kits are with low grade HSS center drills roll-forged. with max cutting depth 1-3/8" (35mm) and ideal for drilling on sheet metal (even high strength metal because of HSS M42 with cobalt 8% teeth), wood, plastic, plasterboard, Aluminium, etc. Particularly for sheet metal: the cutting depth is 2mm to 5mm, depends on the hardness of the metal and taking hand drill or machine drill. HSS bi-metal hole saws are much better than and totally different from any carbon steel ones (work on wood only, no metal). Packed in high quality carrying case.