What size hole should be drilled for an M12 screw?
2 Answers
If tapping is required, the standard pitch for an M12 screw is 1.75mm. Generally, a 10.3mm hole should be drilled. For harder materials like D2, a 10.5-10.7mm hole can be drilled. Below is relevant information: Determining screw type: The drill bit size for an M12 screw depends on the screw type. Even for screws of the same model, the required drill bit size may vary. For example, a 10.3mm drill bit can be used for tapping M12 screws, where the drill bit size is typically the screw diameter minus the pitch. Measuring pitch method: When measuring pitch, it's best to imprint the thread crest on white chalk for clearer marks that facilitate measurement. For metric pitch measurement, measure a length (e.g., 10, 15, or 20mm), count the number of threads in that length, then calculate the pitch. Threads specified in inches use imperial units, such as: G1".
Oh, this is a problem I often encountered at the repair shop before. Be careful when doing it yourself. For a 12mm screw, a 13mm or 13.5mm drill bit is usually the most suitable, because the screw itself has a diameter of 12mm, and a slightly larger hole allows it to pass through the material easily without getting stuck or damaging the screw. Especially when installing brackets or parts on a car, a hole that's too small can cause trouble, such as the threads catching and leading to stripped threads, affecting assembly efficiency. I also recommend checking the sharpness of the drill bit and the hardness of the material; for example, when drilling into steel body panels, a 13.5mm bit is safer, while softer aluminum materials can try a 13mm bit to save effort and avoid waste. In any case, wear safety goggles and gloves when operating, safety first, don't be careless.
