Provided with convex and flat face designs, the QL Shanks are applicable for quarry mining, blast holes, water well and geothermal drilling applications. Supplied with a proprietary heat treatment processes that is extremely effective, these ensure a long service life and advanced strength. Having compressive residual stress layer, the shanks can also manage to improve their resisting capacity against metal fatigue. The convex structured QL Shanks are designed specifically for homogeneous, medium and hard rock formations. These ensure optimum flushing capacity as well as great hole deviation control. Their classic designs allow them to make an excellent penetration rate.