Industrial aluminum profile drilling can be divided into general straight holes and stepped holes; this article mainly introduces stepped holes; the so-called stepped holes are a special drill bit punched into the upper and lower layers of industrial aluminum profiles, the main purpose is to The exposed part of the hidden bolt is not smooth. The head of the frame structure is not smooth on the surface of the frame structure assembled with the stepped holes and bolts. It is also particularly suitable for high-precision instrument frames.