Spiral step drill 1. Step drill is also called pagoda drill. A drill bit can open a plurality of holes to achieve the effect of a drill bit on top of a box of drill bits. 2. You can deburr, chamfer, and expand the hole. 3. The shaking is small, and the beautiful aperture can be opened without the center hole. Recommended tools: pistol drill and bench drill. Inject cooling water while working. The best speed is 250~400 rpm 4.HSS4241 material, the hardness after quenching is 60~63HRC, it can be used for workpieces with hardness below 25 degrees, such as iron plate, aluminum plate and PV plate.
HSS6542 material, after quenching hardness of 63-66HRC, can be used to hardness of 28 degrees below the workpiece, such as iron plate, aluminum plate, sheet metal, copper plate.
The workpiece of HSS M35 is suitable for iron plates, aluminum plates, steel plates and stainless steel plates within 3MM with a hardness of less than 28mm.