The woodworking drill bit is made of 4241 high speed steel, and the body of the center bevel drill bit is NO. Diameter of 45 steel chamfer: 15.8mm. 6mm) to perfectly meet your different needs.Specially designed for sleeve cutters or pilot holes. By loosening and tightening the grub screws with a spanner (included), the corresponding socket depth and the drilling depth can be easily adjusted for different screw lengths. The length of the drill hole can be adjusted for different screw lengths by simply loosening and tightening the screws. The 5-blade chamfer allows faster unloading of wood while drilling, drilling smooth holes in one go, saving you time and labor. The surface of the part will be perfectly integrated with the nut. Compatible with collet drill bits for drilling in hardwood or wooden floors. The position before drilling is recommended to use a center punch, keep the drill vertical and prevent the drill from bending or breaking.