What size hole should be drilled for an M4 screw?
1 Answers
M4 screw's pilot hole is 3.3mm, and the drilling diameter should be 0.7mm. Below is more information about screws: 1. Introduction: Screws include two categories - wood screws and machine screws. Wood screws generally have pointed tips with larger pitches, mainly used for fastening wooden or plastic components; machine screws have flat tips with smaller, uniform pitches, typically used for securing metal or machine parts. 2. Classification: Main categories include common screws, machine screws, self-tapping screws, and expansion screws. 3. Inspection methods: Surface inspection of screws is divided into two types - one is inspection before electroplating after production, and the other is post-electroplating inspection, meaning after hardening and surface treatment. Before electroplating, screws are inspected for dimensions, tolerances, etc., to ensure compliance with national standards or customer requirements. After surface treatment, electroplated screws are mainly inspected for plating color and defective screws.