2072-Lock-tooth fine boring head EWN RFBN small hole SDJ fine boring cutter adjustable tungsten carbide alloy seismic boring bar 10-60Lock tooth fine boring head EWN RFBN small hole SDJ fine boring cutter 1. The tooth head processing strictly adheres to the process of heat treatment and then tapping to avoid the deformation problem caused by post heat treatment, and the blade and the blade are tightly fitted, and the knife is not bounced with high precision 2. SKD61 die steel, quenched and hardened, durable, the surface has been treated Good resistance to acid stains effectively